CERUS CORP
8-K, 1998-07-22
BIOLOGICAL PRODUCTS, (NO DIAGNOSTIC SUBSTANCES)
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<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549



                                    FORM 8-K



                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934



         Date of Report (Date of earliest event reported): JUNE 30, 1998



                                CERUS CORPORATION
             (Exact name of registrant as specified in its charter)



<TABLE>
<S>                                <C>                      <C>       
          DELAWARE                       0-21937                       68-0262011
(State or other jurisdiction of    (Commission File No.)    (IRS Employer Identification No.)
       incorporation)

</TABLE>

                         2525 STANWELL DRIVE, SUITE 300
                                CONCORD, CA 94520
              (Address of principal executive offices and zip code)


       Registrant's telephone number, including area code: (510) 603-9071



<PAGE>   2

ITEM 5.    OTHER EVENTS.

         On June 30, 1998, Cerus Corporation (the "Company") entered into a
series of agreements with Baxter Healthcare Corporation ("Baxter"), pursuant to
which Baxter has agreed to purchase up to $14.5 million of the Company's
preferred stock in connection with the modification of agreements governing the
companies' joint development of pathogen inactivation systems. Copies the
agreements, and the press release announcing the transactions, are filed
herewith as exhibits.


<TABLE>
<CAPTION>
ITEM 7.  EXHIBITS.

<S>      <C>

3.1(2)   Form of Certificate of Designation of Series A Preferred Stock of Cerus
         Corporation.

3.1(3)   Form of Certificate of Designation of Series B Preferred Stock of Cerus
         Corporation.

10.28    Series A Preferred Stock Purchase Agreement, dated as of June 30, 1998,
         by and between Baxter Healthcare Corporation and the Company.

10.29    Series B Preferred Stock Purchase Agreement, dated as of June 30, 1998,
         by and between Baxter Healthcare Corporation and the Company.

10.30    Memorandum of Agreement, dated as of June 30, 1998, by and between
         Baxter Healthcare Corporation and the Company.

10.31    Second Amendment to Development, Manufacturing and Marketing Agreement,
         dated as of June 30, 1998, by and between Baxter Healthcare Corporation
         and the Company.

10.32*   Development, Manufacturing and Marketing Agreement, dated April 1,
         1996, by and between Baxter Healthcare Corporation and the Company, as
         amended and restated June 30, 1998.

99.1     Press Release, dated as of July 8, 1998.
</TABLE>

- -----------

*     The Company has requested confidential treatment with respect to portions
      of this Exhibit.


<PAGE>   3

                                    SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report to be signed on its behalf by the
undersigned, hereunto duly authorized.


                                       CERUS CORPORATION


Dated:  July 21, 1998                  By: /s/  STEPHEN T. ISAACS
                                           -------------------------------------
                                           STEPHEN T. ISAACS
                                           President and Chief Executive Officer



<PAGE>   4

                                  EXHIBIT INDEX

<TABLE>

<S>      <C>

3.1(2)   Form of Certificate of Designation of Series A Preferred Stock of Cerus
         Corporation.

3.1(3)   Form of Certificate of Designation of Series B Preferred Stock of Cerus
         Corporation.

10.28    Series A Preferred Stock Purchase Agreement, dated as of June 30, 1998,
         by and between Baxter Healthcare Corporation and the Company.

10.29    Series B Preferred Stock Purchase Agreement, dated as of June 30, 1998,
         by and between Baxter Healthcare Corporation and the Company.

10.30    Memorandum of Agreement, dated as of June 30, 1998, by and between
         Baxter Healthcare Corporation and the Company.

10.31    Second Amendment to Development, Manufacturing and Marketing Agreement,
         dated as of June 30, 1998, by and between Baxter Healthcare Corporation
         and the Company.

10.32*   Development, Manufacturing and Marketing Agreement, dated April 1,
         1996, by and between Baxter Healthcare Corporation and the Company, as
         amended and restated June 30, 1998.

99.1     Press Release, dated as of July 8, 1998.
</TABLE>

- -----------

*     The Company has requested confidential treatment with respect to portions
      of this Exhibit.


<PAGE>   1
                                                                  EXHIBIT 3.1(2)

                           CERTIFICATE OF DESIGNATION
                           OF SERIES A PREFERRED STOCK
                              OF CERUS CORPORATION


        The undersigned, Stephen T. Isaacs, hereby certifies that:

        1. He is the duly elected and acting President and Secretary,
respectively, of CERUS CORPORATION, a Delaware corporation (the "Company"). The
date of filing of the Amended and Restated Certificate of Incorporation (the
"Certificate") was February 7, 1997.

        2. The Board of Directors of the Company adopted the following recitals
and resolutions as required by Section 151 of the General Company Law of the
State of Delaware at a meeting held on ______________, 1998:

                WHEREAS, the Certificate provides for a class of shares known as
        Preferred Stock, issuable from time to time in one or more series; and

                WHEREAS, the Board of Directors of the Company is authorized by
        Section A of Article IV of the Certificate and, pursuant to its
        authority as aforesaid, desires to fix the terms of the first series of
        said Preferred Stock, the number of shares constituting said series and
        the designation of said series.

                NOW, THEREFORE, BE IT RESOLVED, that the Board of Directors
        deems it advisable to adopt, and hereby adopts, the following
        Certificate of Designation of Preferences of Series A Preferred Stock of
        the Company:

               SECTION 1. DESIGNATION. Five Thousand (5,000) shares of Preferred
Stock, $0.001 par value, are designated "Series A Preferred Stock" with the
powers, preferences, rights, qualifications, limitations and restrictions
specified herein (the "Series A Preferred").

               SECTION 2. VOTING RIGHTS. The holders of shares of Series A
Preferred shall not have any voting rights, except as provided in this Section 2
and as required under the General Corporation Law of Delaware. Without first
obtaining the affirmative vote or written consent of the holders of at least a
majority of the outstanding shares of Series A Preferred, voting as a separate
class, the Company shall not effect any merger or consolidation in which the
Company is not the surviving entity, or any merger, consolidation or other
transaction in which the Company's Common Stock becomes no longer publicly
traded (a "Covered Transaction"), unless the surviving entity in the Covered
Transaction shall have provided for the benefit of the holders of Series A
Preferred contractual rights (the "Contractual Rights") to receive (i) on the
15th day following the Approval Payment Date (as hereinafter defined) or the
Termination Payment Date (as hereinafter defined), as the case may be, the
consideration that the holders of Series A Preferred would have received in the
Covered Transaction had the Series A Preferred been converted into Company
Common Stock immediately prior to the effectuation or consummation of the
Covered Transaction in accordance with the method of conversion used in Section
5(a)(1) or 5(a)(2), as the case may be, at one hundred twenty percent (120%) (in
the case of an Approval Event (as hereinafter defined)), or at one hundred
percent (100%) (in the case of 


                                       1.


<PAGE>   2
a Termination Event (as hereinafter defined)) of the closing price of the
Company's Common Stock immediately prior to the Covered Transaction, (with any
securities that would have been received as part of such consideration being
adjusted for any stock splits, stock combinations and the like from the date of
the Covered Transaction to the date of the Approval Event or the Termination
Event, as the case may be) and (ii) any dividends or other distributions, or
shares issued in any reclassification, exchange or substitution of securities or
in any reorganization, merger or consolidation, that the Series A Preferred
holders would have received from the date of the Covered Transaction to the date
of the Approval Event or Termination Event, as the case may be, in respect of
the securities, if any, that holders of the Series A Preferred would have
received in the Covered Transaction as set forth in (i) above; provided that the
Contractual Rights shall be subject to a right by the surviving entity to
repurchase, and upon a Termination Event, a right of the holders of a majority
of the outstanding shares of the Series A Preferred to require the repurchase
of, the Contractual Rights in the same manner, at the same times and at the same
price as the Company's right to redeem the Series A Preferred pursuant to
Section 4 below.

               SECTION 3. LIQUIDATION RIGHTS.

                      (a) Upon any liquidation, dissolution, or winding up of
the Company, whether voluntary or involuntary, the holders of Series A Preferred
shall be entitled to be paid out of the assets of the Company, before any
payment or distribution of assets of the Company (whether capital or surplus)
shall be made to or set aside for the holders of Common Stock and after and
subordinate to any other class or series of Preferred Stock, an amount per share
of Series A Preferred equal to the "Original Issue Price." The Original Issue
Price of the Series A Preferred shall be One Thousand Dollars ($1,000.00). If,
upon any liquidation, distribution, or winding up, the assets of the Company
shall be insufficient to make payment in full under this Section 3(a) to all
holders of Series A Preferred, then such assets shall be distributed among the
holders of Series A Preferred at the time outstanding, ratably in proportion to
the full stated amounts to which they would otherwise be respectively entitled
under this Section 3(a).

                      (b) The following events shall not be considered a
liquidation, dissolution or winding up under this Section 3:

                           (1) any consolidation or merger of the Company with
or into any other corporation or other entity or person, or any other corporate
reorganization or other transaction or series of transactions resulting in a
change in ownership of the outstanding securities of the Company; or

                           (2) a sale, lease or other disposition of all or any
part of the assets of the Company.

               SECTION 4. REDEMPTION.

                      (a) Upon (i) the approval of a new drug application (NDA)
or pre-market approval (PMA) or equivalent by the United States Food and Drug
Administration under the Development, Manufacturing and Marketing Agreement
dated as of December 10, 1993 between the Company and Baxter Healthcare
Corporation, as amended from time to time (the "Platelet Agreement") or (ii) CE
Mark approval in Europe under the Platelet Agreement (either, 


                                       2.


<PAGE>   3
an "Approval Event"), the Company shall have the right to redeem all or any
portion of the Series A Preferred at the Original Issue Price.

                      (b) Upon the termination for any reason of the Platelet
Agreement or upon cessation for any reason of the Cooperative Development Work
(as such term is defined in the Platelet Agreement) (either, a "Termination
Event"), the Company shall have the right, and the holders of a majority of the
outstanding shares of Series A Preferred shall have the right to require the
Company, to redeem all, but not less than all, the Series A Preferred at the
Original Issue Price.

                      (c) Immediately prior to consummation of a Covered
Transaction, the Company shall have the right to redeem all, but not less than
all, shares of Series A Preferred Stock then outstanding at the Original Issue
Price.

                      (d) In the event the Company desires to redeem the Series
A Preferred pursuant to Section 4(a), the Company shall, within ten (10) days
after the Approval Payment Date (as defined below), send a notice to the Series
A Preferred holders notifying the holders of redemption and setting forth the
number of shares of Series A Preferred to be redeemed and the total amount to be
paid for the shares of Series A Preferred being redeemed (the "Redemption
Price"). If, at the time of any redemption pursuant to Section 4(a) for less
than all of the Series A Preferred, there shall be more than one holder of the
Series A Preferred, such redemption shall be made pro rata among the holders of
the Series A Preferred in proportion to the number of shares of Series A
Preferred held by each such holder. The "Approval Payment Date" means the date
on which the Company receives payment of the amount payable to it under Section
4.3 of the Platelet Agreement

                      (e) In the event the Company or the holders of a majority
of the outstanding shares of the Series A Preferred desires to have the Series A
Preferred redeemed pursuant to Section 4(b) above, the Company or the Series A
Preferred holders shall, within ten (10) days after the Termination Payment Date
(as defined below), send a notice to the Company or the Series A Preferred
holders, as the case may be, stating that the Series A Preferred shall be
redeemed pursuant to this subsection (e). The amount to be paid for the Series A
Preferred being redeemed shall also be referred to as the "Redemption Price."
The "Termination Payment Date" means the date on which the Company receives
payment of the amount payable to it under Section 13.4 of the Platelet
Agreement.

                      (f) In the event the Company desires to have the Series A
Preferred redeemed pursuant to Section 4(c) above, the Company shall, not less
than ten (10) days before the date of consummation of the Covered Transaction,
send a notice to the Series A Preferred holders indicating that the Series A
Preferred shall be redeemed pursuant to this subsection (f). The amount to be
paid for the Series A Preferred being redeemed shall also be referred to as the
"Redemption Price."

                      (g) Within five (5) days after receipt of a redemption
notice from the Company or within five (5) days after the sending of a
redemption notice to the Company pursuant to Section 4(d), Section 4(e) or
Section 4(f) above, as the case may be, the Series A Preferred holders shall
surrender that number of Series A Preferred share certificates set forth in a
redemption notice by the Company, in the case of redemption pursuant to Section
4(a) above, 


                                       3.


<PAGE>   4
or all Series A Preferred share certificates, in the case of redemption pursuant
to Section 4(b) or Section 4(c) above, at the principal executive office of the
Company, and thereupon the Redemption Price shall be payable, in cash by wire
transfer or certified check, to the order of the person whose name appears on
such certificate or certificates as the owner thereof and each surrendered
certificate shall be canceled. Notwithstanding the foregoing, the Redemption
Price payable upon a redemption in connection with a Covered Transaction will be
payable, and the share certificates for the Series A Preferred shall be
canceled, only upon consummation of the Covered Transaction. If the Company does
not have sufficient funds legally available to redeem all shares to be redeemed
pursuant to this Section 4, then it shall use those funds which are legally
available to redeem the maximum possible number of such shares pro rata among
the holders of the Series A Preferred Stock. At any time thereafter when funds
of the Company are legally available for the redemption of shares of Series A
Preferred, such funds will immediately be used to redeem the balance of the
shares which the Company has become obligated to redeem pursuant to this Section
4 but which it has not redeemed. In the event that a redemption notice is given
pursuant to Section 4(f) above in connection with an impending Covered
Transaction, and the Covered Transaction is later terminated without being
consummated, the Company will so notify the holders of the Series A Preferred
Stock, and the redemption notice and redemption will be deemed rescinded and any
tendered share certificates will be returned to the holders of the Series A
Preferred, with the same effect as if such redemption notice had not been given.

               SECTION 5. CONVERSION RIGHTS. The following provisions shall
apply with respect to the conversion of the Series A Preferred into shares of
Common Stock:

                      (a) Conversion.

                           (1) Subject to Section 5(a)(3) below, upon the
occurrence of an Approval Event, if a notice of redemption of the Series A
Preferred has not been sent by the Company pursuant to Section 4(d) above, each
share of Series A Preferred shall automatically be converted into that number of
fully paid and nonassessable shares of Common Stock equal to the Original Issue
Price divided by one hundred twenty percent (120%) of the average closing price
of the Common Stock, as reported in The Wall Street Journal, for the thirty (30)
trading days prior to and including the trading day immediately prior to the
Approval Event. The date on which such conversion shall occur shall be the 15th
day following the Approval Payment Date.

                           (2) Subject to Section 5(a)(3) below, upon the
occurrence of a Termination Event, if a redemption notice has not been sent by
the Company or the holder of the Series A Preferred pursuant to Section 4(e)
above, each share of Series A Preferred shall automatically be converted into
that number of fully paid and nonassessable shares of Common Stock equal to the
Original Issue Price divided by the average closing price of the Common Stock,
as reported in The Wall Street Journal, for the thirty (30) trading days
commencing with the fifteenth (15th) trading day prior to the Termination Event.
The date on which such conversion shall occur shall be the 15th day following
the Termination Payment Date.

                           (3) Notwithstanding anything contained in this
Section 5 to the contrary, the Series A Preferred shall not convert, and no
shares of Common Stock shall be issued by the Company thereby, unless and until
the pre-merger notification requirements of the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended (the "HSR Act"), have been complied with,
and any waiting period under the HSR Act applicable to the conversion of the


                                       4.


<PAGE>   5
Series A Preferred has expired or been terminated and any approvals required
thereunder have been obtained.

                           (4) Upon the conversion of the Series A Preferred
pursuant to this Section 5, the outstanding shares of Series A Preferred shall
be converted automatically without any further action by the holders of such
shares and whether or not the certificates representing such shares are
surrendered to the Company or its transfer agent; provided, however, that the
Company shall not be obligated to issue certificates evidencing the shares of
Common Stock issuable upon such conversion unless the certificates evidencing
such shares of Series A Preferred are either delivered to the Company or its
transfer agent as provided below, or the holder notifies the Company or its
transfer agent that such certificates have been lost, stolen or destroyed and
executes an agreement satisfactory to the Company to indemnify the Company from
any loss incurred by it in connection with such certificates. Upon the
occurrence of such automatic conversion of the Series A Preferred, the holders
of Series A Preferred shall surrender the certificates representing such shares
at the office of the Company or any transfer agent for the Series A Preferred.
Thereupon, there shall be issued and delivered to such holder promptly at such
office and in its name as shown on such surrendered certificate or certificates,
a certificate or certificates for the number of shares of Common Stock into
which the shares of Series A Preferred surrendered were convertible on the date
on which such automatic conversion occurred.

                           (5) Notwithstanding anything contained in this
Section 5 to the contrary, in the event that the approval of the Company's
stockholders is required pursuant to Rule 4460(i) of the Nasdaq Stock Market
("Rule 4460(i)") prior to the issuance of any of the shares of Common Stock
issuable upon conversion of the Series A Preferred, the Company shall obtain
such approval by the applicable conversion date under Section 5(a)(i) or 5(a)(2)
hereof. In the event such approval is not obtained by the applicable conversion
date, the Company shall, in accordance with Section 4 hereof, redeem any shares
of Series A Preferred that would be convertible into shares of Common Stock in
excess of the limitation specified in Rule 4460(i).

                      (b) FRACTIONAL SHARES. No fractional shares of Common
Stock shall be issued upon conversion of Series A Preferred and the number of
shares of Common Stock to be issued shall be rounded down to the nearest whole
share. The Company shall, in lieu of issuing any fractional share, pay the
holder otherwise entitled to such fraction a sum in cash equal to the fair
market value of such fraction on the date of conversion (as determined in good
faith by the Board of Directors).

                      (c) RESERVATION OF STOCK ISSUABLE UPON CONVERSION. The
Company shall at all times reserve and keep available out of its authorized but
unissued shares of Common Stock or its treasury shares, solely for the purpose
of effecting the conversion of the shares of the Series A Preferred, such number
of its shares of Common Stock as shall from time to time be sufficient to effect
the conversion of all outstanding shares of the Series A Preferred. If at any
time the number of authorized but unissued shares of Common Stock shall not be
sufficient to effect the conversion of all then outstanding shares of the Series
A Preferred, the Company will take such corporate action as may, in the opinion
of its counsel, be necessary to increase its authorized but unissued shares of
Common Stock to such number of shares as shall be sufficient for such purpose.


                                       5.


<PAGE>   6
                      (d) NOTICES. Any notice required by the provisions of this
Section 5 to be given to the holders of shares of the Series A Preferred shall
be deemed given upon the earlier of actual receipt or seventy-two (72) hours
after the same has been deposited in the United States mail, by certified or
registered mail, return receipt requested, and addressed to each holder of
record at the address of such holder appearing on the books of the Company.

                      (e) PAYMENT OF TAXES. The Company will pay all taxes
(other than taxes based upon income) and other governmental charges that may be
imposed with respect to the issue or delivery of shares of Common Stock upon
conversion of shares of Series A Preferred, excluding any tax or other charge
imposed in connection with any transfer involved in the issue and delivery of
shares of Common Stock in a name other than that in which the shares of Series A
Preferred so converted were registered.


               SECTION 6. NOTICES OF RECORD. Upon any taking by the Company of a
record of the holders of any class of securities for the purpose of determining
the holders thereof who are entitled to receive any dividend or other
distribution, or upon any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company, any
merger or consolidation of the Company with or into any other corporation, or
any transfer of all or substantially all the assets of the Company to any other
person, or any voluntary or involuntary dissolution, liquidation or winding up
of the Company, or any shareholders' meeting to approve the terms thereof, the
Company shall mail to each holder of Series A Preferred at least twenty (20)
days prior to the record date specified therein a notice specifying (i) the date
on which any such record is to be taken for the purpose of such dividend or
distribution and a description of such dividend or distribution, (ii) the date
on which any such reorganization, reclassification, transfer, consolidation,
merger, dissolution, liquidation or winding up is expected to become effective,
and the date of the shareholders meeting to approve the terms thereof, if
applicable, (iii) the date, if any, that is to be fixed as to when the holders
of record of Common Stock (or other securities) shall be entitled to exchange
their shares of Common Stock (or other securities) for securities or other
property deliverable upon such reorganization, reclassification, transfer,
consolidation, merger, dissolution, liquidation or winding up, and (iv) the
material terms thereof.

               SECTION 7. NO REISSUANCE OF PREFERRED STOCK. No share or shares
of Series A Preferred acquired by the Company by reason of redemption, purchase,
conversion or otherwise shall be reissued.

               SECTION 8. RESTRICTION ON TRANSFER. Neither the shares of Series
A Preferred nor any right to receive redemption payments, nor any Contractual
Rights, shall be assigned, transferred, hypothecated or otherwise alienated by
the holder thereof without the prior written consent of the Company, except (i)
in connection with, and to the transferee of, all or substantially all of the
business and assets of such holder, or (ii) to a direct or indirect wholly owned
subsidiary of Baxter International, Inc. Any such attempted action shall be null
and void. The foregoing restriction shall not apply to any Common Stock issued
on conversion of the Preferred Stock.

               SECTION 9. CANCELLATION OF PREFERRED STOCK. Upon the effectuation
or consummation of any Covered Transaction pursuant to which the holders of the
Series A Preferred receive the Contractual Rights, the Series A Preferred shall
be canceled.



                                       6.
<PAGE>   7
                RESOLVED FURTHER, that the President, the Chief Financial
        Officer or the Secretary be, and each of them hereby is, authorized to
        execute, verify and file, for and on behalf of the Company, the
        Certificate of Designation of Preferences with the Delaware Secretary of
        State in accordance with the General Company Law of the State of
        Delaware.

                RESOLVED FURTHER, that the officers of the Company be, and each
        of them hereby is, authorized and directed in the name and on behalf of
        the Company and under its corporate seal if appropriate, to execute and
        deliver all agreements and instruments, effect all filings and
        qualifications, and take all further action which is necessary or
        appropriate to carry out the foregoing resolutions.

        3. The authorized number of shares of Preferred Stock of this Company is
five million (5,000,000), none of which has been issued.


                           CERTIFICATE OF DESIGNATION
                               SERIES A PREFERRED


<PAGE>   8
IN WITNESS WHEREOF, this Company has caused this Certificate to be signed by its
duly authorized officer this _____ day of July, 1998.


                                    CERUS CORPORATION



                                    By:
                                       -------------------------------------
                                       Stephen T. Isaacs
                                       President


                           CERTIFICATE OF DESIGNATION
                               SERIES A PREFERRED



<PAGE>   1
                                                                  EXHIBIT 3.1(3)

                           CERTIFICATE OF DESIGNATION
                           OF SERIES B PREFERRED STOCK
                              OF CERUS CORPORATION


        The undersigned, Stephen T. Isaacs, hereby certifies that:

        1. He is the duly elected and acting President of CERUS CORPORATION, a
Delaware corporation (the "Company"). The date of filing of the Amended and
Restated Certificate of Incorporation (the "Certificate") was February 7, 1997.

        2. The Board of Directors of the Company adopted the following recitals
and resolutions as required by Section 151 of the General Company Law of the
State of Delaware by unanimous written consent dated ______________, 1998:

                WHEREAS, the Certificate provides for a class of shares known as
        Preferred Stock, issuable from time to time in one or more series; and

                WHEREAS, the Board of Directors of the Company is authorized by
        Section A of Article IV of the Certificate and, pursuant to its
        authority as aforesaid, desires to fix the terms of the second series of
        said Preferred Stock, the number of shares constituting said series and
        the designation of said series.

                NOW, THEREFORE, BE IT RESOLVED, that the Board of Directors
        deems it advisable to adopt, and hereby adopts, the following
        Certificate of Designation of Preferences of Series B___ Preferred Stock
        of the Company:

               SECTION 1. DESIGNATION. _______________ (_________) shares of
Preferred Stock, $0.001 par value, are designated "Series B___ Preferred Stock"
with the powers, preferences, rights, qualifications, limitations and
restrictions specified herein (the "Series B___ Preferred"). The Series B___
Preferred Stock is further designated as a sub-series of Series B Preferred
Stock.

               SECTION 2. VOTING RIGHTS. The holders of shares of Series B___
Preferred shall not have any voting rights, except as provided in Section 2,
Section 3(c)(1)(C), Section 3(c)(2) hereof, and as required under the General
Corporation Law of Delaware. Without first obtaining the affirmative vote or
written consent of the holders of at least a majority of the outstanding shares
of each series of Preferred Stock that is designated as a sub-series of Series B
Preferred Stock, voting together as a separate class, the Company shall not
authorize or issue shares of any class or series of stock, or reclassify any
class or series of stock, including without limitation, the Company's Common
Stock, into shares having preference or priority over the Series B Preferred as
to voting, liquidation preference or conversion rights.

               SECTION 3. LIQUIDATION RIGHTS.

                      (a) Upon any liquidation, dissolution, or winding up of
the Company, whether voluntary or involuntary, before any payment or
distribution of assets of the Company (whether capital or surplus) shall be made
to or set aside for the holders of Common Stock,


                                       1.


<PAGE>   2
Series A Preferred Stock, or any other class or series of stock ranking junior
to the Series B Preferred with respect to liquidation preference, the holders of
Series B___ Preferred shall be entitled to be paid out of the assets of the
Company an amount per share of Series B___ Preferred equal to the "Original
Issue Price." The Original Issue Price of the Series B___ Preferred shall be
____________________ Dollars ($__________). If, upon any liquidation,
distribution, or winding up, the assets of the Company shall be insufficient to
make payment in full under this Section 3(a) to all holders of Series B___
Preferred, then such assets shall be distributed among the holders of Series
B___ Preferred at the time outstanding, ratably in proportion to the full stated
amounts to which they would otherwise be respectively entitled under this
Section 3(a).

                      (b) The following events shall be considered a
liquidation, dissolution or winding up under this Section 3:

                           (1) any consolidation or merger of the Company with
or into any other corporation or other entity or person in which the Company is
not the surviving entity, or any other consolidation, merger, corporate
reorganization or other transaction or series of transactions pursuant to which
the holders of the outstanding voting securities of the Company immediately
prior to such consolidation, merger, reorganization or other transaction or
series of transactions fail to hold equity securities representing a majority of
the voting power of the surviving entity immediately following such
consolidation, merger or reorganization or any transaction or series of related
transactions; or

                           (2) a sale, lease or other disposition of all or
substantially all of the assets of the Company.

                      (c) Any securities to be delivered to the holders of the
Series B Preferred pursuant to a transaction treated as a liquidation shall be
valued as follows:

                           (1) Securities not subject to investment letter or
other similar restrictions on free marketability:

                                (a) If traded on a national securities exchange
or the National Market System of the National Association of Securities Dealers,
Inc. (the "NMS"), the value shall be deemed to be the average of the security's
closing prices on such exchange or the NMS over the thirty (30) day period
ending three (3) days prior to the closing;

                                (b) If traded over-the-counter (but not on the
NMS), the value shall be deemed to be the average of the mean of the closing bid
and ask prices over the thirty (30) day period ending three (3) days prior to
the closing; or

                                (c) If there is no active public market, the
value shall be the fair market value thereof, as mutually determined by the
Board of Directors of the Company and the holders of a majority of the
outstanding Series B Preferred, voting together as a single class.

                           (2) The method of valuation of securities subject to
investment letter or other restrictions on free marketability shall be to make
an appropriate discount from the 


                                       2.


<PAGE>   3
market value determined as above in Sections 3(c)(1)(A), (B) or (C) to reflect
the approximate fair market value thereof, as mutually determined by the Board
of Directors of the Company and the holders of not less than a majority of the
outstanding Series B Preferred, voting together as a single class.

               SECTION 4. REDEMPTION.

                      (a) The Company may elect to redeem all, but not less than
all, of the outstanding Series B___ Preferred at the Original Issue Price at any
time, from funds legally available for redemption. Without limiting the
foregoing, the Company shall have the right to redeem the outstanding Series
B___ Preferred within _____________ (___) days after receipt of a Conversion
Notice (as defined below). Any redemption pursuant to this Section 4(b) shall be
for all shares of Series B___ Preferred then outstanding. In the event the
Company desires to redeem the Series B___ Preferred pursuant to this subsection
(b), the Company shall send a notice to the Series B___ Preferred holder stating
that the Series B___ Preferred shall be redeemed pursuant to this subsection
(b); provided that, if such notice is in response to a Conversion Notice, the
notice must be sent within ______________ (_____) days of receipt of the
Conversion Notice. The amount to be paid for the Series B___ Preferred being
redeemed shall be referred to as the "Redemption Price."

                      (b) Within five (5) days after receipt of a redemption
notice from the Company pursuant to Section 4(a) above, the Series B___
Preferred holders shall surrender all Series B___ Preferred share certificates
at the principal executive office of the Company, and thereupon the Redemption
Price shall be payable, in cash to the order of the person whose name appears on
such certificate or certificates as the owner thereof and each surrendered
certificate shall be canceled. If the Company does not have sufficient funds
legally available to redeem all shares to be redeemed pursuant to this Section
4, then it shall use those funds which are legally available to redeem the
maximum possible number of such shares pro rata among the holders of the Series
B ___ Preferred Stock. At any time thereafter when funds of the Company are
legally available for the redemption of shares of Series B___ Preferred, such
funds will immediately be used to redeem the balance of the shares which the
Company has become obligated to redeem pursuant to this Section 4 but which it
has not redeemed.

               SECTION 5. CONVERSION RIGHTS. The following provisions shall
apply with respect to the conversion of the Series B___ Preferred into shares of
Common Stock:

                      (a) OPTIONAL CONVERSION.

                           (1) At any time after the one-year anniversary of the
date of issuance of the Series B___ Preferred, each share of Series B___
Preferred may, at the option of the holder, be converted at any time into that
number of fully paid and nonassessable shares of Common Stock equal to the
Original Issue Price divided by the Conversion Price (as defined below), subject
to the Company's right to redeem the Series B___ Preferred pursuant to Section
4(a) above. The conversion price for the Series B ___Preferred shall initially
be equal to the Original Issue Price divided by 100 (the "Conversion Price").
Such initial Conversion Price shall be adjusted from time to time in accordance
with this Section 5. All references to the Conversion Price herein shall mean
the Conversion Price as so adjusted.


                                       3.


<PAGE>   4
                           (2) Notwithstanding anything contained in this
Section 5 to the contrary, the Series B___ Preferred shall not convert, and no
shares of Common Stock shall be issued by the Company thereby, unless and until
the pre-merger notification requirements of the Hart-Scott-Rodino Antitrust
Improvements Act of 1976, as amended (the "HSR Act"), have been complied with,
and any waiting period under the HSR Act applicable to the conversion of the
Series B___ Preferred has expired or been terminated and any approvals required
thereunder have been obtained.

                           (3) Before any holder of Series B___ Preferred shall
be entitled to convert the same into shares of Common Stock, such holder shall
surrender the certificate or certificates therefor, duly endorsed, at the
principal executive office of the Company or its transfer agent for such stock,
and shall give written notice to the corporation at such office that such holder
elects to convert the Series B Preferred and shall state therein the name or
names in which the holder wishes the certificate or certificates for shares of
Common Stock to be issued (the "Conversion Notice"). The Company shall, as soon
as practicable thereafter, issue and deliver at such office to such holder of
Series B ___ Preferred at the holder's address as set forth on the Company's
records, or such other address as the holder shall have furnished to the Company
in writing, a certificate or certificates for the number of shares of Common
Stock to which such holder shall be entitled as aforesaid. Such conversion shall
be deemed to have been made immediately prior to the close of business on the
date of surrender of the shares of Series B ___ Preferred to be converted, and
the person or persons entitled to receive the shares of Common Stock issuable
upon such conversion shall be treated for all purposes as the record holder or
holders of such shares of Common Stock on such date.


                           (4) Notwithstanding anything contained in this
Section 5 to the contrary, in the event that the approval of the Company's
stockholders is required pursuant to Rule 4460(i) of the Nasdaq Stock Market
prior to the issuance of any of the shares of Common Stock issuable upon
conversion of the Series B Preferred, the Company shall obtain such approval by
the conversion date under Section 5(a)(1) hereof. In the event such approval is
not obtained, the Company shall, in accordance with Section 4 hereof, redeem any
shares of Series B Preferred that would be convertible into shares of Common
Stock in excess of the limitation specified in Rule 4460(i).


                      (b) ADJUSTMENT FOR STOCK SPLITS AND COMBINATIONS. If the
Company shall at any time or from time to time after the date that the first
share of Series B ___ Preferred is issued (the "Original Issue Date") fix a
record date for the effectuation of a split or subdivision of the outstanding
Common Stock, the Conversion Price for the Series B ___ Preferred in effect
immediately before that subdivision shall be proportionately decreased.
Conversely, if the Company shall at any time or from time to time after the
Original Issue Date combine the outstanding shares of Common Stock into a
smaller number of shares, the Conversion Price for the Series B ___ Preferred in
effect immediately before the combination shall be proportionately increased.
Any adjustment under this Section 5(b) shall become effective at the close of
business on the date the split, subdivision or combination becomes effective.

                      (c) ADJUSTMENT FOR COMMON STOCK DIVIDENDS AND
DISTRIBUTIONS. If the Company at any time or from time to time after the
Original Issue Date makes, or fixes a 


                                       4.


<PAGE>   5
record date for the determination of holders of Common Stock entitled to
receive, a dividend or other distribution payable in additional shares of Common
Stock, in each such event the Conversion Price for the Series B ___ Preferred
that is then in effect shall be decreased as of the time of such issuance or, in
the event such record date is fixed, as of the close of business on such record
date, by multiplying the Conversion Price then in effect by a fraction (i) the
numerator of which is the total number of shares of Common Stock issued and
outstanding immediately prior to the time of such issuance or the close of
business on such record date, and (ii) the denominator of which is the total
number of shares of Common Stock issued and outstanding immediately prior to the
time of such issuance or the close of business on such record date plus the
number of shares of Common Stock issuable in payment of such dividend or
distribution; provided, however, that if such record date is fixed and such
dividend is not fully paid or if such distribution is not fully made on the date
fixed therefor, the Conversion Price shall be recomputed accordingly as of the
close of business on such record date and thereafter the Conversion Price shall
be adjusted pursuant to this Section 5(c) to reflect the actual payment of such
dividend or distribution or other securities or rights convertible into, or
entitling the holder thereof to receive directly or indirectly, additional
shares of Common Stock.

                      (d) ADJUSTMENTS FOR OTHER DIVIDENDS AND DISTRIBUTIONS. If
the Company at any time or from time to time after the Original Issue Date makes
or fixes a record date for the determination of holders of Common Stock entitled
to receive a dividend or other distribution payable in securities of the Company
other than shares of Common Stock, in each such event for purposes of this
subsection 5(d), provision shall be made so that the holders of the Series B ___
Preferred shall receive upon conversion thereof, in addition to the number of
shares of Common Stock receivable thereupon, the amount of other securities of
the Company which they would have received had their Series B ___ Preferred been
converted into Common Stock as of the record date fixed for the determination of
the holders of Common Stock of the Company entitled to receive such distribution
and had they thereafter, during the period from the date of such event to and
including the conversion date, retained such securities receivable by them as
aforesaid during such period, subject to all other adjustments called for during
such period under this Section 5 with respect to the rights of the holders of
the Series B ___ Preferred or with respect to such other securities by their
terms.

                      (e) ADJUSTMENT FOR RECLASSIFICATION, EXCHANGE AND
SUBSTITUTION. If at any time or from time to time after the Original Issue Date,
the Common Stock issuable upon the conversion of the Series B ___ Preferred is
changed into the same or a different number of shares of any class or classes of
stock, whether by recapitalization, reclassification or otherwise (other than a
subdivision or combination of shares or stock dividend or a reorganization,
merger, consolidation or sale of assets provided for elsewhere in this Section 5
or in Section 3), in any such event each holder of Series B ___ Preferred shall
have the right thereafter to convert such stock into the kind and amount of
stock and other securities and property receivable upon such recapitalization,
reclassification or other change by holders of the maximum number of shares of
Common Stock into which such shares of Series B ___ Preferred could have been
converted immediately prior to or as of such recapitalization, reclassification
or change, all subject to further adjustment as provided herein or with respect
to such other securities or property by the terms thereof. In any such case,
appropriate adjustment shall be made in the application of the provisions of
this Section 5 with respect to the rights of the holders of Series B ___
Preferred after such recapitalization, reclassification or change to the end
that the provisions of this 


                                       5.


<PAGE>   6
Section 5 (including adjustment of the Conversion Price then in effect and the
number of shares issuable upon conversion of the Series B ___ Preferred) shall
be applicable after that event and be as nearly equivalent as practicable.

                      (f) REORGANIZATIONS. If at any time or from time to time
after the Original Issue Date, there is a capital reorganization of the Common
Stock (other than a recapitalization, subdivision, combination,
reclassification, exchange or substitution of shares provided for elsewhere in
this Section 5 or in Section 3), as a part of such capital reorganization,
provision shall be made so that the holders of the Series B ___ Preferred shall
thereafter be entitled to receive upon conversion of the Series B ___ Preferred
the number of shares of stock or other securities or property of the Company or
otherwise to which a holder of the number of shares of Common Stock deliverable
upon conversion would have been entitled on such capital reorganization, subject
to adjustment in respect of such stock or securities by the terms thereof. In
any such case, appropriate adjustment shall be made in the application of the
provisions of this Section 5 with respect to the rights of the holders of Series
B ___ Preferred after the capital reorganization to the end that the provisions
of this Section 5 (including adjustment of the Conversion Price then in effect
and the number of shares issuable upon conversion of the Series B ___ Preferred)
shall be applicable after that event and be as nearly equivalent as practicable.


                      (g) FRACTIONAL SHARES. No fractional shares of Common
Stock shall be issued upon conversion of Series B___ Preferred and the number of
shares of Common Stock to be issued shall be rounded down to the nearest whole
share. The Company shall, in lieu of issuing any fractional share, pay the
holder otherwise entitled to such fraction a sum in cash equal to the fair
market value of such fraction on the date of conversion (as determined in good
faith by the Board of Directors).

                      (h) RESERVATION OF STOCK ISSUABLE UPON CONVERSION. The
Company shall at all times reserve and keep available out of its authorized but
unissued shares of Common Stock or its treasury shares, solely for the purpose
of effecting the conversion of the shares of the Series B___ Preferred, such
number of its shares of Common Stock as shall from time to time be sufficient to
effect the conversion of all outstanding shares of the Series B___ Preferred. If
at any time the number of authorized but unissued shares of Common Stock shall
not be sufficient to effect the conversion of all then outstanding shares of the
Series B___ Preferred, the Company will take such corporate action as may, in
the opinion of its counsel, be necessary to increase its authorized but unissued
shares of Common Stock to such number of shares as shall be sufficient for such
purpose.

                      (i) NOTICES. Any notice required by the provisions of this
Section 5 to be given to the holders of shares of the Series B___ Preferred
shall be deemed given upon the earlier of actual receipt or seventy-two (72)
hours after the same has been deposited in the United States mail, by certified
or registered mail, return receipt requested, and addressed to each holder of
record at the address of such holder appearing on the books of the Company.

                      (j) PAYMENT OF TAXES. The Company will pay all taxes
(other than taxes based upon income) and other governmental charges that may be
imposed with respect to the issue or delivery of shares of Common Stock upon
conversion of shares of Series B___ Preferred, excluding any tax or other charge
imposed in connection with any transfer involved in 


                                       6.


<PAGE>   7
the issue and delivery of shares of Common Stock in a name other than that in
which the shares of Series B___ Preferred so converted were registered.


                      (k) NO DILUTION OR IMPAIRMENT. The Company shall not amend
its Certificate of Incorporation or participate in any reorganization, transfer
of assets, consolidation, merger, dissolution, issue or sale of securities or
any other voluntary action, for the purpose of avoiding or seeking to avoid the
observance or performance of any of the terms to be observed or performed
hereunder by the Company, but shall at all times in good faith assist in
carrying out all such action as may be reasonably necessary or appropriate in
order to protect the conversion rights of the holders of the Series B Preferred
against dilution or other impairment.

               SECTION 6. NOTICES OF RECORD. Upon any taking by the Company of a
record of the holders of any class of securities for the purpose of determining
the holders thereof who are entitled to receive any dividend or other
distribution, or upon any capital reorganization of the Company, any
reclassification or recapitalization of the capital stock of the Company, any
merger or consolidation of the Company with or into any other corporation, or
any transfer of all or substantially all the assets of the Company to any other
person, or any voluntary or involuntary dissolution, liquidation or winding up
of the Company, or any shareholders' meeting to approve the terms thereof, the
Company shall mail to each holder of Series B___ Preferred at least twenty (20)
days prior to the record date specified therein a notice specifying (i) the date
on which any such record is to be taken for the purpose of such dividend or
distribution and a description of such dividend or distribution, (ii) the date
on which any such reorganization, reclassification, transfer, consolidation,
merger, dissolution, liquidation or winding up is expected to become effective,
and the date of the shareholders meeting to approve the terms thereof, if
applicable, (iii) the date, if any, that is to be fixed as to when the holders
of record of Common Stock (or other securities) shall be entitled to exchange
their shares of Common Stock (or other securities) for securities or other
property deliverable upon such reorganization, reclassification, transfer,
consolidation, merger, dissolution, liquidation or winding up, and (iv) the
material terms thereof.

               SECTION 7. NO REISSUANCE OF SERIES B ___ PREFERRED STOCK. No
share or shares of Series B___ Preferred acquired by the Company by reason of
redemption, purchase, conversion or otherwise shall be reissued.

               SECTION 8. RESTRICTION ON TRANSFER. Neither the shares of Series
B ___ Preferred nor any right to receive redemption payments shall be assigned,
transferred, hypothecated or otherwise alienated by the holder thereof without
the prior written consent of the Company, except (i) in connection with, and to
the transferee of, all or substantially all of the business and assets of such
holder, or (ii) to a direct or indirect wholly owned subsidiary of Baxter
International Inc. Any such attempted action shall be null and void. The
foregoing restriction shall not apply to any Common Stock issued on conversion
of the Series B ___ Preferred.

               RESOLVED FURTHER, that the President, the Chief Financial Officer
        or the Secretary be, and each of them hereby is, authorized to execute,
        verify and file, for and on behalf of the Company, the Certificate of
        Designation of Preferences with the Delaware Secretary of State in
        accordance with the General Company Law of the State of Delaware.


                                       7.


<PAGE>   8
               RESOLVED FURTHER, that the officers of the Company be, and each
        of them hereby is, authorized and directed in the name and on behalf of
        the Company and under its corporate seal if appropriate, to execute and
        deliver all agreements and instruments, effect all filings and
        qualifications, and take all further action which is necessary or
        appropriate to carry out the foregoing resolutions.

        3. The authorized number of shares of Preferred Stock of this Company is
five million (5,000,000), of which 5,000 shares designated as Series A Preferred
Stock are issued and outstanding.


                                       8.


<PAGE>   9
        IN WITNESS WHEREOF, this Company has caused this Certificate to be
signed by its duly authorized officer this _____ day of ____________________,
1998.

                                       CERUS CORPORATION



                                       By:
                                            -------------------------------
                                            Stephen T. Isaacs
                                            President


                           CERTIFICATE OF DESIGNATION
                              SERIES B___ PREFERRED


<PAGE>   1
                                                                   EXHIBIT 10.28

                                CERUS CORPORATION

                   SERIES A PREFERRED STOCK PURCHASE AGREEMENT

                                  JUNE 30, 1998



<PAGE>   2


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                  PAGE
<S>      <C>                                                                      <C>
1.       AGREEMENT TO SELL AND PURCHASE..............................................1

         1.1      Authorization of Shares............................................1

         1.2      Sale and Purchase of the Shares....................................1

         1.3      Sale Exclusively to Purchaser......................................1

2.       CLOSING, DELIVERY AND PAYMENT...............................................1

3.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY...............................2

         3.1      Organization, Good Standing and Qualification......................2

         3.2      Authorization; Binding Obligations.................................2

         3.3      Compliance With Other Instruments..................................2

         3.4      Securities Exemption...............................................2

         3.5      Subsidiaries.......................................................2

         3.6      Valid Issuance of Shares...........................................2

         3.7      Litigation, Etc....................................................3

         3.8      Governmental Consents..............................................3

4.       REPRESENTATIONS AND WARRANTIES OF PURCHASER.................................3

         4.1      Requisite Power and Authority......................................3

         4.2      Consents...........................................................3

         4.3      Investment Representations.........................................3

5.       LEGENDS.....................................................................4

6.       CONDITIONS TO CLOSING.......................................................5

         6.1      Conditions to Purchaser's Obligations at the Closing...............5

         6.2      Conditions to Obligations of the Company...........................6

7.       MISCELLANEOUS...............................................................6

         7.1      Governing Law......................................................6

         7.2      Survival...........................................................6

         7.3      Successors and Assigns.............................................6

         7.4      Registration Rights................................................7

         7.5      Redemption of Shares...............................................7

         7.6      Entire Agreement...................................................7

         7.7      Separability.......................................................7
</TABLE>


<PAGE>   3

                                TABLE OF CONTENTS
                                   (CONTINUED)
<TABLE>
<CAPTION>
                                                                                  PAGE
<S>      <C>                                                                      <C>

         7.8      Amendment and Waiver...............................................7

         7.9      Delays or Omissions................................................8

         7.10     Notices............................................................8

         7.11     Expenses...........................................................8

         7.12     Attorneys' Fees....................................................8

         7.13     Titles and Subtitles...............................................8

         7.14     Counterparts.......................................................8

         7.15     Broker's Fees......................................................8

         7.16     Subsequent Consents, Permits and Waivers...........................9

</TABLE>

                                      ii.
<PAGE>   4

                                CERUS CORPORATION
                   SERIES A PREFERRED STOCK PURCHASE AGREEMENT

         THIS SERIES A PREFERRED STOCK PURCHASE AGREEMENT (the "Agreement") is
entered into as of June 30, 1998, by and between CERUS CORPORATION, a Delaware
corporation (the "Company"), and BAXTER HEALTHCARE CORPORATION, a Delaware
corporation ("Purchaser").

                                    RECITALS

         WHEREAS, Purchaser desires to purchase shares of the Company's Series A
Preferred Stock; and

         WHEREAS, the Company desires to issue and sell shares of its Series A
Preferred Stock to Purchaser on the terms and conditions set forth herein.

         NOW, THEREFORE, in consideration of the foregoing recitals and the
mutual promises hereinafter set forth, the parties hereto agree as follows:

1.       AGREEMENT TO SELL AND PURCHASE.

         1.1 AUTHORIZATION OF SHARES. The Company will authorize the sale and
issuance to Purchaser of Five Thousand (5,000) shares of its Series A Preferred
Stock (the "Shares") and will designate sufficient shares of Series A Preferred
Stock to cover the sale and issuance of the Shares to be purchased hereunder.
The Certificate of Designation of the Series A Preferred Stock will be in the
form attached as Exhibit A to this Agreement.

         1.2 SALE AND PURCHASE OF THE SHARES. Subject to the terms and
conditions hereof, the Company hereby agrees to issue and sell to Purchaser and
Purchaser agrees to purchase from the Company, at the Closing, the Shares at a
purchase price per share of $1,000.00.

         1.3 SALE EXCLUSIVELY TO PURCHASER. The Company will sell shares of
Series A Preferred Stock exclusively to Purchaser.

2.       CLOSING, DELIVERY AND PAYMENT.

         The closing of the sale and purchase of the Shares under this Agreement
(the "Closing") shall take place two business days after the satisfaction of the
conditions to closing set forth in Section 6 hereof at the offices of Cooley
Godward LLP, One Maritime Plaza, 20th floor, San Francisco, California 94111.
The date of the Closing is referred to as the "Closing Date." At the Closing,
subject to the terms and conditions hereof, the Company will, or will instruct
the transfer agent to, deliver to Purchaser a certificate representing the
number of Shares to be purchased at the Closing against payment by or on behalf
of Purchaser of the purchase price therefor by cash, wire transfer, or by such
other means as shall be mutually agreeable to Purchaser and the Company.



                                       1.
<PAGE>   5

3.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

         The Company hereby represents and warrants to Purchaser as follows:

         3.1 ORGANIZATION, GOOD STANDING AND QUALIFICATION. The Company is a
corporation duly incorporated, validly existing and in good standing under the
laws of the State of Delaware. The Company has full power and authority to own
and operate its properties and assets, and to carry on its business as presently
conducted and as proposed to be conducted. The Company is duly qualified, is
authorized to do business and is in good standing as a foreign corporation in
all jurisdictions in which the nature of its activities and of its properties
(both owned and leased) makes such qualification necessary, except for those
jurisdictions, in the aggregate, in which failure to do so would not have a
material adverse effect on the Company or its business.

         3.2 AUTHORIZATION; BINDING OBLIGATIONS. All corporate action on the
part of the Company, its officers, directors and stockholders necessary for the
authorization, execution and delivery of this Agreement, for the sale and
issuance of the Shares pursuant hereto (and the shares of Common Stock issuable
upon conversion of the Shares) and for the performance of the Company's
obligations hereunder, has been taken or will be taken prior to the Closing.
This Agreement, when executed and delivered, will be a valid and binding
obligation of the Company enforceable in accordance with its terms (i) except as
limited by applicable bankruptcy, insolvency, reorganization, moratorium or
other laws of general application affecting enforcement of creditors' rights and
(ii) subject to general principles of equity that restrict the availability of
equitable remedies. The sale of the Shares is not and will not be subject to any
preemptive rights or rights of first refusal that have not been properly waived
or complied with.

         3.3 COMPLIANCE WITH OTHER INSTRUMENTS. The execution, delivery and
performance of and compliance with this Agreement and the sale of the Shares
pursuant hereto will not result in (i) any violation, or be in conflict with or
constitute a default under any term, of its Certificate of Incorporation or
Bylaws, (ii) any material violation or default of any mortgage, indenture,
material contract or agreement, instrument, judgment, decree, order or any
statute, rule or regulation applicable to the Company or (iii) the creation of
any mortgage, pledge, lien, encumbrance or charge upon any of the properties or
assets of the Company.

         3.4 SECURITIES EXEMPTION. Assuming the accuracy of the representations
and warranties of the Purchaser contained in Section 4.3 hereof, the offer, sale
and issuance of the Shares will be exempt from the registration requirements of
the Securities Act of 1933, as amended (the "Securities Act"), and will have
been registered or qualified (or are exempt from registration and qualification)
under the registration, permit or qualification requirements of all applicable
state securities laws.

         3.5 SUBSIDIARIES. The Company does not presently own or control,
directly or indirectly, and has no stock or other interest as owner or principal
in, any other corporation or partnership, joint venture, association or other
business venture or entity.

         3.6 VALID ISSUANCE OF SHARES. When issued in compliance with the
provisions of this Agreement and the Certificate of Incorporation, the Shares
will be validly issued, fully paid and 


                                       2.
<PAGE>   6

nonassessable, and will be free of any liens or encumbrances; provided, however,
that the Shares may be subject to restrictions on transfer under state and/or
federal securities laws as set forth herein or as otherwise required by such
laws at the time a transfer is proposed. The Common Stock issuable upon
conversion of the Shares has been duly and validly reserved and, when issued in
compliance with the provisions of this Agreement and the Certificate of
Incorporation, will be duly and validly issued, fully paid and nonassessable and
free of restrictions on transfer other than restrictions under applicable
federal and state securities laws.

         3.7 LITIGATION, ETC. There is no action, suit, proceeding nor, to the
best of the Company's knowledge, any investigation pending or currently
threatened against the Company, that questions the validity of this Agreement or
the right of the Company to enter into this Agreement.

         3.8 GOVERNMENTAL CONSENTS. No consent, approval, order or authorization
of, or registration, qualification, designation, declaration or filing with, any
federal, state, local or provincial governmental authority on the part of the
Company is required in connection with the consummation of the transactions
contemplated by this Agreement, except for notices required or permitted to be
filed with certain state and federal securities commissions, which notices will
be filed by the Company on a timely basis.

4.       REPRESENTATIONS AND WARRANTIES OF PURCHASER.

         Purchaser hereby represents and warrants to the Company as follows
(such representations and warranties do not lessen or obviate the
representations and warranties of the Company set forth in this Agreement):

         4.1 REQUISITE POWER AND AUTHORITY. Purchaser has all necessary power
and authority under all applicable provisions of law to execute and deliver this
Agreement and to carry out the provisions of this Agreement. All action on
Purchaser's part required for the lawful execution and delivery of this
Agreement has been or will be effectively taken prior to the Closing. This
Agreement, when executed and delivered, will be a valid and binding obligation
of Purchaser, enforceable in accordance with its terms (i) except as limited by
applicable bankruptcy, insolvency, reorganization, moratorium or other laws of
general application affecting enforcement of creditors' rights and (ii) subject
to general principles of equity that restrict the availability of equitable
remedies.

         4.2 CONSENTS. All consents, approvals, orders, authorizations,
registrations, qualifications, designations, declarations or filings with any
governmental or banking authority on the part of Purchaser required in
connection with the consummation of the transactions contemplated in this
Agreement have been or shall have been obtained prior to and be effective as of
the Closing.

         4.3 INVESTMENT REPRESENTATIONS. Purchaser understands that the Shares
have not been registered under the Securities Act. Purchaser also understands
that the Shares are being offered and sold pursuant to an exemption from
registration contained in the Securities Act based in part upon Purchaser's
representations contained in the Agreement. Purchaser hereby represents and
warrants as follows:



                                       3.
<PAGE>   7

                  (a) PURCHASER IS AN ACCREDITED INVESTOR. Purchaser represents
that Purchaser is an Accredited Investor within the meaning of Rule 501(a) of
Regulation D under the Securities Act.

                  (b) PURCHASER BEARS ECONOMIC RISK. Purchaser must bear the
economic risk of this investment indefinitely unless the Shares are registered
pursuant to the Securities Act, or an exemption from registration is available.
Purchaser understands that it has no registration rights with respect to the
Shares. Purchaser also understands that there is no assurance that any exemption
from registration under the Securities Act will be available and that, even if
available, such exemption may not allow Purchaser to transfer all or any portion
of the Shares under the circumstances, in the amounts or at the times Purchaser
might propose.

                  (c) ACQUISITION FOR OWN ACCOUNT. Purchaser is acquiring the
Shares for Purchaser's own account for investment only, and not with a view
towards their distribution within the meaning of the Securities Act.

                  (d) PURCHASER CAN PROTECT ITS INTEREST. Purchaser represents
that by reason of its, or of its management's, business or financial experience,
Purchaser has the capacity to protect its own interests in connection with the
transactions contemplated in this Agreement. Purchaser is not a corporation,
trust or partnership specifically formed for the purpose of consummating these
transactions.

                  (e) COMPANY INFORMATION. Purchaser has had an opportunity to
discuss the Company's business, management and financial affairs with directors,
officers and management of the Company and has had the opportunity to review the
Company's operations and facilities. Purchaser has also had the opportunity to
ask questions of and receive answers from, the Company and its management
regarding the terms and conditions of this investment.

5.       LEGENDS.

         Each certificate or other document evidencing any of the Shares or any
Common Stock issued upon conversion thereof shall be endorsed with the legends
in the form substantially as set forth in paragraphs (a) and (c) below, and each
certificate or other document evidencing the Shares, but not any such Common
Stock issued upon conversion of the Shares, shall be endorsed with the legend
substantially in the form set forth in paragraph (b) below, and Purchaser
covenants that, except to the extent such restrictions are waived by the
Company, Purchaser shall not transfer the Shares represented by any such
certificate without complying with restrictions on transfer described in the
legends endorsed on such certificate. Notwithstanding the foregoing, upon
registration of any Common Stock issued upon conversion of the Shares under the
Securities Act of 1933, the provisions of this Section shall no longer apply and
the Company shall promptly exchange the certificates representing such Common
Stock with unlegended certificates.

                  (a)      The following legend under the Act:

                           THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE
                           NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933
                           (THE "ACT"). THEY MAY NOT BE SOLD OR OFFERED FOR SALE



                                       4.
<PAGE>   8

                           OR OTHERWISE DISTRIBUTED UNLESS THE SECURITIES ARE
                           REGISTERED UNDER THE ACT OR AN EXEMPTION THEREFROM IS
                           AVAILABLE.

                  (b)      The following legend:

                           THE SHARES REPRESENTED BY THIS CERTIFICATE ARE
                           SUBJECT TO RESTRICTIONS ON TRANSFER AS PROVIDED IN
                           THE CERTIFICATE OF DESIGNATION OF SERIES A PREFERRED
                           STOCK OF CERUS CORPORATION, A COPY OF WHICH MAY BE
                           OBTAINED UPON WRITTEN REQUEST FROM THE SECRETARY OF
                           THE CORPORATION AT ITS PRINCIPAL OFFICE.

                  (c) Any legend imposed or required by applicable state
securities laws.

6.       CONDITIONS TO CLOSING.

         6.1 CONDITIONS TO PURCHASER'S OBLIGATIONS AT THE CLOSING. Purchaser's
obligation to purchase the Shares identified in Section 1.1 of the Agreement at
the Closing are subject to the satisfaction, at or prior to the Closing, of the
following conditions:

                  (a) REPRESENTATIONS AND WARRANTIES TRUE; PERFORMANCE OF
OBLIGATIONS. The representations and warranties made by the Company in Section 3
hereof shall be true and correct in all material respects as of the Closing with
the same force and effect as if they had been made as of the Closing, and the
Company shall have performed and complied with all obligations and conditions
herein required to be performed or complied with by it on or prior to the
Closing.

                  (b) LEGAL INVESTMENT. At the time of the Closing, the sale and
issuance of the Shares shall be legally permitted by all laws and regulations to
which Purchaser and the Company are subject.

                  (c) CONSENTS, PERMITS AND WAIVERS. The Company shall have
obtained any and all authorizations, approvals, consents, permits and waivers
necessary or appropriate for consummation of the transactions contemplated by
this Agreement (except for such as may be properly obtained subsequent to the
Closing, and such items shall be effective on and as of the Closing).

                  (d) CERTIFICATE OF GOOD STANDING. The Company shall have
obtained a Certificate of Good Standing from the Delaware Secretary of State
dated as of a recent date prior to the Closing.

                  (e) OPINION LETTER. Purchaser shall have received from Cooley
Godward LLP, counsel to the Company, an opinion letter addressed to it, dated
the date of the Closing, in substantially the form attached hereto as Exhibit B.

                  (f) PROCEEDINGS AND DOCUMENTS. All corporate and other
proceedings in connection with the transactions contemplated at the Closing and
all documents and instruments 


                                       5.
<PAGE>   9

incident to such transactions shall be reasonably satisfactory in form and
substance to counsel to Purchaser, and counsel to Purchaser shall have received
all such counterpart originals or certified or other copies of such documents as
they may reasonably request.

                  (g) COMPLIANCE CERTIFICATE. The Company shall have delivered
to Purchaser a Compliance Certificate, executed by the President and the Chief
Financial Officer of the Company, dated the Closing Date, to the effect that the
conditions specified in subparagraphs (a) through (f) of this Section 6.1 have
been satisfied.

                  (h) REGISTRATION RIGHTS. The Company shall have obtained the
Requisite Approval as set forth in Section 7.4 hereof.

         6.2 CONDITIONS TO OBLIGATIONS OF THE COMPANY. The Company's obligation
to issue and sell the Shares at the Closing is subject to the satisfaction, on
or prior to the Closing, of the following conditions:

                  (a) REPRESENTATIONS AND WARRANTIES TRUE. The representations
and warranties made by Purchaser in Section 4 hereof shall be true and correct
in all material respects at the date of the Closing, with the same force and
effect as if they had been made on and as of said date.

                  (b) PERFORMANCE OF OBLIGATIONS. Purchaser shall have performed
and complied with all agreements and conditions herein required to be performed
or complied with by Purchaser on or before the Closing.

7.       MISCELLANEOUS.

         7.1 GOVERNING LAW. This Agreement shall be governed in all respects by
the laws of the State of California.

         7.2 SURVIVAL. The representations, warranties, covenants and agreements
made herein shall survive any investigation made by Purchaser and the closing of
the transactions contemplated hereby. All statements as to factual matters
contained in any certificate or other instrument delivered by or on behalf of
the Company pursuant hereto in connection with the transactions contemplated
hereby shall be deemed to be representations and warranties by the Company
hereunder solely as of the date of such certificate or instrument, except as
expressly provided otherwise in such certificate or instrument. Section 1.3
hereof shall survive the Closing.

         7.3 SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors and administrators of the
parties hereto and shall inure to the benefit of and be enforceable by each
person who shall be a holder of the Shares from time to time; provided, however,
that prior to the receipt by the Company of adequate written notice of the
transfer of any Shares specifying the full name and address of the transferee,
the Company may deem and treat the person listed as the holder of such Shares in
its records as the absolute owner and holder of such Shares for all purposes,
the payment of any dividends or any redemption price.



                                       6.
<PAGE>   10

         7.4 REGISTRATION RIGHTS. Subject to the approval of the requisite
holders of "Registrable Securities" (the "Requisite Approval") under the Amended
and Restated Investors' Rights Agreement, dated as of April 1, 1996, between the
Company and the investors thereto (the "Rights Agreement"), the Common Stock
issuable upon conversion of the Shares shall be Registrable Securities as
defined in Section 1.3 of the Rights Agreement. Subject to the Requisite
Approval, by signing this Agreement, Purchaser agrees to be bound by the Rights
Agreement as a party thereto. Cerus will use its best efforts to obtain such
approval on or before July 15, 1998. Baxter, as a holder of Registrable
Securities, hereby consents to such action, and agrees to execute such other
instruments as shall be appropriate to evidence such approval.

         7.5 REDEMPTION OF SHARES. If the Company elects to redeem the Shares,
as provided for in the Certificate of Designation of the Series A Preferred
Stock and indebtedness is then owing from Purchaser to the Company, the Company
and Purchaser will consider and discuss whether to permit the Company to pay all
or a portion of the redemption price through cancellation of indebtedness. If
the parties can not agree to such arrangement, the redemption price will be paid
in cash.

         7.6 ENTIRE AGREEMENT. This Agreement, the Rights Agreement, and the
other documents delivered pursuant hereto and thereto constitute the full and
entire understanding and agreement between the parties with regard to the
subjects hereof and no party shall be liable or bound to any other in any manner
by any representations, warranties, covenants and agreements except as
specifically set forth herein. Nothing in this Agreement, express or implied, is
intended to confer upon any party, other than the parties hereto, and their
respective successors and assigns, any rights, remedies, obligations or
liabilities under or by reason of this Agreement, except as expressly provided
herein.

         7.7 SEPARABILITY. In case any provision of the Agreement shall be
invalid, illegal or unenforceable, such provision shall, to the extent
practicable, be modified so as to make it valid, legal and enforceable and to
maintain as nearly as practicable the intent of the parties, and the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby.

         7.8      AMENDMENT AND WAIVER.

                  (a) This Agreement may be amended or modified only upon the 
written consent of the parties hereto.

                  (b) The obligations of the Company and the rights of the
holder of the Shares under this Agreement may be waived only with the written
consent of the parties hereto.

                  (c) Except to the extent provided in this Section 7.8, neither
this Agreement nor any provision hereof may be changed, waived, discharged or
terminated, except by a statement in writing signed by the party against which
enforcement of the change, waiver, discharge or termination is sought.

                  (d) Any amendment or waiver effected in accordance with this
Section 7.8 shall be binding upon any future holder of some or all of the
Shares.



                                       7.
<PAGE>   11

         7.9 DELAYS OR OMISSIONS. It is agreed that no delay or omission to
exercise any right, power or remedy accruing to Purchaser, upon any breach,
default or noncompliance of the Company under this Agreement or the Certificate
of Incorporation shall impair any such right, power or remedy, nor shall it be
construed to be a waiver of any such breach, default or noncompliance, or any
acquiescence therein, or of or in any similar breach, default or noncompliance
thereafter occurring. It is further agreed that any waiver, permit, consent or
approval of any kind or character on Purchaser's part of any breach, default or
noncompliance under this Agreement or the Certificate of Incorporation or any
waiver on Purchaser's part of any provisions or conditions of this Agreement
must be in writing and shall be effective only to the extent specifically set
forth in such writing. All remedies under this Agreement, the Certificate of
Incorporation or Bylaws, or otherwise afforded to Purchaser, shall be cumulative
and not alternative.

         7.10 NOTICES. All notices and other communications required or
permitted hereunder shall be in writing and shall be deemed effectively given
and received (a) upon personal delivery, (b) on the fifth day following mailing
sent by registered or certified mail, return receipt requested, postage prepaid,
(c) upon confirmed delivery by means of a nationally recognized overnight
courier service or (d) upon transmission of facsimile (with telephonic notice)
addressed: (i) if to Purchaser, at Purchaser's address as set forth on the
Company's records, or at such other address as Purchaser shall have furnished to
the Company in writing or (ii) if to the Company, at its address as set forth at
the end of this Agreement, or at such other address as the Company shall have
furnished to Purchaser in writing.

         7.11 EXPENSES. The Company shall pay all costs and expenses that it
incurs with respect to the negotiation, execution, delivery and performance of
the Agreement, and Purchaser shall pay all costs and expenses that it incurs
with respect to the negotiation, execution, delivery and performance of this
Agreement.

         7.12 ATTORNEYS' FEES. If legal action is brought to enforce or
interpret this Agreement, the prevailing party shall be entitled to recover its
reasonable attorneys' fees and legal costs in connection therewith.

         7.13 TITLES AND SUBTITLES. The titles of the paragraphs and
subparagraphs of the Agreement are for convenience of reference only and are not
to be considered in construing this Agreement.

         7.14 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one instrument.

         7.15 BROKER'S FEES. Each party hereto represents and warrants that no
agent, broker, investment banker, person or firm acting on behalf of or under
the authority of such party hereto is or will be entitled to any broker's or
finder's fee or any other commission directly or indirectly in connection with
the transactions contemplated herein. Each party hereto further agrees to
indemnify each other party for any claims, losses or expenses incurred by such
other party as a result of the representation in this Section 7.15 being untrue.



                                       8.
<PAGE>   12

         7.16 SUBSEQUENT CONSENTS, PERMITS AND WAIVERS. The Company shall obtain
promptly after the Closing all authorizations, approvals, consents, permits and
waivers that are necessary or applicable for consummation of the transactions
contemplated by this Agreement and that were not obtained prior to the Closing
because they may be properly obtained subsequent to the Closing.


                                       9.
<PAGE>   13


         IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date set forth in the first paragraph hereof.

COMPANY:

CERUS CORPORATION:
2525 Stanwell Drive
Concord, CA  94520



By:_________________________________
         Stephen T. Isaacs
         President

PURCHASER:

BAXTER HEALTHCARE CORPORATION
One Baxter Parkway
Deerfield, Illinois  60015

By:_________________________________
         (Signature)

Name:_______________________________

Its:________________________________




                                      10.

<PAGE>   14

                                    EXHIBIT A

             CERTIFICATE OF DESIGNATION OF SERIES A PREFERRED STOCK



                                       1.

<PAGE>   15


                                    EXHIBIT B

                                 FORM OF OPINION

July ___, 1998

Baxter Healthcare Corporation
One Baxter Parkway
Deerfield, IL  60015

Re:      Cerus Corporation

Ladies and Gentlemen:

         We have acted as counsel to Cerus Corporation, a Delaware corporation
(the "Company"), in connection with the issuance and sale to you of the Shares
(as defined in the Series A Preferred Stock Purchase Agreement between you and
the Company, dated as of June 30, 1998 (the "Purchase Agreement"), such issuance
and sale to take place pursuant to the terms and conditions of the Purchase
Agreement. We are rendering this opinion pursuant to Section 6.1(e) of the
Purchase Agreement. Except as otherwise defined herein, capitalized terms used
but not defined herein have the respective meanings given to them in the
Purchase Agreement.

         In connection with this opinion, we have examined and relied upon the
representations and warranties as to factual matters contained in and made
pursuant to the Agreement by the various parties and originals or copies
certified to our satisfaction, of such records, documents, certificates,
opinions, memoranda and other instruments as in our judgment are necessary or
appropriate to enable us to render the opinion expressed below. Where we render
an opinion "to the best of our knowledge" or concerning an item "known to us" or
our opinion otherwise refers to our knowledge, it is based solely upon (i) an
inquiry of attorneys within this firm who perform legal services for the
Company, (ii) receipt of a certificate executed by an officer of the Company
covering such matters, and (iii) such other investigation, if any, that we
specifically set forth herein.

         In rendering this opinion, we have assumed the genuineness and
authenticity of all signatures on original documents; the authenticity of all
documents submitted to us as originals; the conformity to originals of all
documents submitted to us as copies; the accuracy, completeness and authenticity
of certificates of public officials; and the due authorization, execution and
delivery of all documents (except the due authorization, execution and delivery
by the Company of the Purchase Agreement) where authorization, execution and
delivery are prerequisites to the effectiveness of such documents. We have also
assumed that all individuals executing and delivering documents in their
individual capacities had the legal capacity to so execute and deliver; that you
have received all documents you were to receive under the Purchase Agreement;
that the Purchase Agreement is an obligation binding upon you; that you have
filed any required California franchise or income tax returns and have paid any
required California franchise or income taxes; and that there are no extrinsic
agreements or understandings among the parties to the Purchase Agreement that
would modify or interpret the terms of the Purchase Agreement or the respective
rights or obligations of the parties thereunder.



                                       1.
<PAGE>   16

         Our opinion is expressed only with respect to the federal laws of the
United States of America, the laws of the State of California and the General
Corporation Law of the State of Delaware. We express no opinion as to whether
the laws of any particular jurisdiction apply, and no opinion to the extent that
the laws of any jurisdiction other than those identified above are applicable to
the subject matter hereof. We are not rendering any opinion as to compliance
with any antifraud law, rule or regulation relating to securities, or to the
sale or issuance thereof.

         With respect to the opinion in paragraph 3 hereof regarding issued and
outstanding capital stock of the Company, we have examined and have relied
solely on a certificate furnished by the Company's transfer agent, Norwest Bank
Minnesota, N.A., a copy of which has been made available to you. We have
undertaken no independent verification with respect thereto.

         With regard to our opinion in paragraph 4 below with respect to
material defaults under any of the Material Agreements (as defined below), we
have relied solely upon (i) inquiries of officers of the Company, (ii) a list
supplied to us by the Company of material agreements to which the Company is a
party, or by which it is bound (the "Material Agreements"), and (iii) an
examination of the items on the aforementioned list; we have made no further
investigation.

         On the basis of the foregoing, in reliance thereon and with the
foregoing qualifications, we are of the opinion that:

         1. The Company has been duly incorporated and is a validly existing
corporation in good standing under the laws of the State of Delaware. The
Company has the requisite corporate power to own its property and assets and to
conduct its business as it is currently being conducted.

         2. The Purchase Agreement has been duly and validly authorized,
executed and delivered by the Company and constitutes a legal, valid and binding
agreement of the Company enforceable against the Company in accordance with its
terms, except as enforcement may be limited by applicable bankruptcy,
insolvency, reorganization, arrangement with creditors, moratorium or other
similar laws affecting creditors' rights, and subject to general equity
principles and to limitations on availability of equitable relief, including
specific performance.

         3. The Company's authorized capital stock consists of (a) fifty million
(50,000,000) shares of Common Stock, of which ________________________________
(_________) are issued and outstanding, and (b) five million (5,000,000) shares
of Preferred Stock, of which five thousand (5,000) shares have been designated
Series A Preferred Stock, none of which (excluding the Shares to be issued at
Closing) are issued and outstanding. The outstanding shares of Common Stock have
been duly authorized, validly issued and are fully paid and nonassessable. The
rights, preferences and privileges of the Series A Preferred Stock are as stated
in the Certificate of Designation of Series A Preferred Stock. The Shares have
been duly and validly authorized, and upon issuance and delivery against payment
therefor in accordance with the Purchase Agreement will be validly issued,
outstanding, fully paid and nonassessable. The Shares of Common Stock issuable
upon conversion of the Shares have been duly authorized, and upon issuance and
delivery upon conversion thereof in accordance with the terms of the Shares,
will be validly issued, outstanding, fully paid and nonassessable.



                                       2.
<PAGE>   17

         4. The execution, delivery and performance of the Purchase Agreement by
the Company and the offer, issuance and sale of the Shares pursuant thereto (a)
do not constitute a material default under, and do not result in a lien or other
encumbrance on the property of the Company pursuant to, the provisions of any of
the Material Agreements, (b) do not violate any provision of the Company's
Certificate of Incorporation or Bylaws, and (c) do not violate or contravene any
governmental statute, rule or regulation applicable to the Company.

         5. To the best of our knowledge, there is no action, suit, proceeding
or investigation pending or overtly threatened against the Company before any
domestic or foreign court or administrative agency that questions the validity
of the Purchase Agreement.

         6. All consents, approvals, authorizations or orders of, and filings,
registrations and qualifications with any regulatory authority or governmental
body in the United States required for the consummation by the Company of the
offer, issuance and sale of the Shares contemplated by the Purchase Agreement
have been made or obtained.

         This opinion is intended solely for your benefit and is not to be made
available to or be relied upon by any other person, firm, or entity without our
prior written consent.

Very truly yours,

COOLEY GODWARD LLP



By:___________________________
    Howard G. Ervin



                                       3.

<PAGE>   1
                                                                   EXHIBIT 10.29



                                CERUS CORPORATION

                   SERIES B PREFERRED STOCK PURCHASE AGREEMENT

                                  JUNE 30, 1998



<PAGE>   2

                                CERUS CORPORATION

                   SERIES B PREFERRED STOCK PURCHASE AGREEMENT

This SERIES B PREFERRED STOCK PURCHASE AGREEMENT (the "Agreement") is entered
into as of June 30, 1998, by and between CERUS CORPORATION, a Delaware
corporation (the "Company"), and BAXTER HEALTHCARE CORPORATION, a Delaware
corporation ("Purchaser").

                                    RECITALS

WHEREAS, Purchaser desires to purchase shares of the Company's Series B
Preferred Stock (the "Shares"); and

WHEREAS, the Company desires to issue and sell the Shares to Purchaser on the
terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the foregoing recitals and the mutual
promises hereinafter set forth, the parties hereto agree as follows:

1.       AGREEMENT TO SELL AND PURCHASE.

         1.1 SALE AND PURCHASE OF THE SHARES. If the Company has not completed
an equity offering of at least Twenty Million Dollars ($20,000,000) by August
31, 1998, then at any time on or after October 1, 1998 until September 30, 1999,
subject to the terms and conditions hereof, Purchaser agrees to purchase from
the Company that number of Shares having an aggregate purchase price set forth
in a written notice or notices given by the Company to Purchaser at any time
before 5:00 p.m. Central Time on September 30, 1999 (a "Notice"); provided,
however, that the number of Shares purchased pursuant to this Agreement shall
not exceed an aggregate purchase price of Nine Million Five Hundred Thousand
Dollars ($9,500,000). The Company may elect to cause such sale of shares to
occur either in one tranche of Nine Million Five Hundred Thousand Dollars
($9,500,000) or in two tranches of Five Million Dollars ($5,000,000) and Four
Million Five Hundred Thousand Dollars ($4,500,000), respectively. Any Notice
given by the Company to Purchaser pursuant to this Section 1.1 shall be sent by
registered or certified mail (return receipt requested) or a nationally
recognized overnight delivery service to Purchaser's address as set forth on the
Company's records or such other address as Purchaser shall have furnished the
Company in writing, and shall be deemed given when postmarked or delivered to
the delivery service. The purchase price per Share shall equal the open market
price per share for the Company's Common Stock multiplied by 100. "Open market
price" shall mean the average of the closing sales prices of the Company's
Common Stock, as reported on the Nasdaq Stock Market's National System, on the
30 trading days prior to and including the trading day that is two days before
the Closing Date (as defined below).

         1.2 AUTHORIZATION OF SHARES. The Company will authorize the sale and
issuance to Purchaser of the number of Shares determined in accordance with
Section 1.1 hereof. Prior to the Closing Date, the Company shall have designated
a sufficient number of Shares to cover the 


                                       1.
<PAGE>   3

sale and issuance of the Shares to be purchased hereunder. The Series B
Preferred Stock to be sold pursuant to this Agreement shall be designated in
sub-series for each Closing (as defined below) (i.e., at the first Closing,
Series B1 Preferred shall be sold and issued; at the second Closing, Series B2
Preferred Stock shall be sold and issued). The Certificate of Designation for
each sub-series of Series B Preferred Stock shall be in substantially the form
set forth on Exhibit A hereto.

         1.3 SALE EXCLUSIVELY TO PURCHASER. The Company will sell shares of
Series B Preferred Stock, including any sub-series thereof, exclusively to
Purchaser.

         1.4 PREMIUM. In the event that the Company completes an equity
financing or financings of at least Twenty Million Dollars ($20,000,000) in the
aggregate (a "Financing") (excluding purchases by Baxter Healthcare Corporation
of affiliate thereof), the Company shall pay to Purchaser a premium equal to
seven percent (7.0%) per annum interest on the purchase price of Shares
purchased hereunder, computed from the tenth business day following the date of
the Closing of the Financing until the earliest of (a) the date of redemption of
the Shares, (b) the date of conversion of the Shares into Common Stock or (c)
one year from the Closing Date of the Financing, on which earliest date such
Premium shall be paid in full.

2.       CLOSING, DELIVERY AND PAYMENT.

Subject to the terms of Section 6, each closing of the sale and purchase of the
Shares under this Agreement (a "Closing") shall take place at the offices of
Cooley Godward LLP, One Maritime Plaza, 20th floor, San Francisco, California
94111, on the day that is five (5) trading days after the date the Notice is
given pursuant to Section 1.1 hereof. The date of each Closing is referred to as
the "Closing Date." At the Closing, subject to the terms and conditions hereof,
the Company will, or will instruct the transfer agent to, deliver to Purchaser a
certificate representing the number of Shares to be purchased at the Closing
against payment by or on behalf of Purchaser of the purchase price therefor by
cash, wire transfer, or by such other means as shall be mutually agreeable to
Purchaser and the Company.

3.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY.

As of the date of the Agreement, the Company hereby represents and warrants to
Purchaser as follows:

         3.1 ORGANIZATION, GOOD STANDING AND QUALIFICATION. The Company is a
corporation duly incorporated, validly existing and in good standing under the
laws of the State of Delaware. The Company has full power and authority to own
and operate its properties and assets, and to carry on its business as presently
conducted and as proposed to be conducted. The Company is duly qualified, is
authorized to do business and is in good standing as a foreign corporation in
all jurisdictions in which the nature of its activities and of its properties
(both owned and leased) makes such qualification necessary, except for those
jurisdictions, in the aggregate, in which failure to do so would not have a
material adverse effect on the Company or its business.

         3.2 AUTHORIZATION; BINDING OBLIGATIONS. All corporate action on the
part of the Company, its officers, directors and stockholders necessary for the
authorization, execution and 


                                       2.
<PAGE>   4

delivery of this Agreement, for the sale and issuance of the Shares pursuant
hereto (and the shares of Common Stock issuable upon conversion of the Shares)
and for the performance of the Company's obligations hereunder, has been taken
or will be taken prior to the Closing. This Agreement, when executed and
delivered, will be a valid and binding obligation of the Company enforceable in
accordance with its terms (i) except as limited by applicable bankruptcy,
insolvency, reorganization, moratorium or other laws of general application
affecting enforcement of creditors' rights and (ii) subject to general
principles of equity that restrict the availability of equitable remedies. The
sale of the Shares is not and will not be subject to any preemptive rights or
rights of first refusal that have not been properly waived or complied with.

         3.3 COMPLIANCE WITH OTHER INSTRUMENTS. The execution, delivery and
performance of and compliance with this Agreement and the sale of the Shares
pursuant hereto will not result in (i) any violation, or be in conflict with or
constitute a default under any term, of its Certificate of Incorporation or
Bylaws, (ii) any material violation or default of any mortgage, indenture,
material contract or agreement, instrument, judgment, decree, order or any
statute, rule or regulation applicable to the Company or (iii) the creation of
any mortgage, pledge, lien, encumbrance or charge upon any of the properties or
assets of the Company.

         3.4 SECURITIES EXEMPTION. Assuming the accuracy of the representations
and warranties of the Purchaser contained in Section 4.3 hereof, the offer, sale
and issuance of the Shares will be exempt from the registration requirements of
the Securities Act of 1933, as amended (the "Securities Act"), and will have
been registered or qualified (or are exempt from registration and qualification)
under the registration, permit or qualification requirements of all applicable
state securities laws.

         3.5 SUBSIDIARIES. The Company does not presently own or control,
directly or indirectly, and has no stock or other interest as owner or principal
in, any other corporation or partnership, joint venture, association or other
business venture or entity.

         3.6 VALID ISSUANCE OF SHARES. When issued in compliance with the
provisions of this Agreement and the Certificate of Incorporation, the Shares
will be validly issued, fully paid and nonassessable, and will be free of any
liens or encumbrances; provided, however, that the Shares may be subject to
restrictions on transfer under state and/or federal securities laws as set forth
herein or as otherwise required by such laws at the time a transfer is proposed.
The Common Stock issuable upon conversion of the Shares has been duly and
validly reserved and, when issued in compliance with the provisions of this
Agreement and the Certificate of Incorporation, will be duly and validly issued,
fully paid and nonassessable and free of restrictions on transfer other than
restrictions under applicable federal and state securities laws.

         3.7 LITIGATION, ETC. There is no action, suit, proceeding nor, to the
best of the Company's knowledge, any investigation pending or currently
threatened against the Company, that questions the validity of this Agreement or
the right of the Company to enter into this Agreement, or which might result,
either individually or in the aggregate, in any material adverse change in the
assets, condition, affairs or prospects of the Company, financial or otherwise.

         3.8 GOVERNMENTAL CONSENTS. No consent, approval, order or authorization
of, or registration, qualification, designation, declaration or filing with, any
federal, state, local or


                                       3.
<PAGE>   5

provincial governmental authority on the part of the Company is required in
connection with the consummation of the transactions contemplated by this
Agreement, except for notices required or permitted to be filed with certain
state and federal securities commissions, which notices will be filed by the
Company on a timely basis.

4.       REPRESENTATIONS AND WARRANTIES OF PURCHASER.

As of the date of this Agreement, Purchaser hereby represents and warrants to
the Company as follows (such representations and warranties do not lessen or
obviate the representations and warranties of the Company set forth in this
Agreement):

         4.1 REQUISITE POWER AND AUTHORITY. Purchaser has all necessary power
and authority under all applicable provisions of law to execute and deliver this
Agreement and to carry out the provisions of this Agreement. All action on
Purchaser's part required for the lawful execution and delivery of this
Agreement has been or will be effectively taken prior to the Closing. This
Agreement, when executed and delivered, will be a valid and binding obligation
of Purchaser, enforceable in accordance with its terms (i) except as limited by
applicable bankruptcy, insolvency, reorganization, moratorium or other laws of
general application affecting enforcement of creditors' rights and (ii) subject
to general principles of equity that restrict the availability of equitable
remedies.

         4.2 CONSENTS. All consents, approvals, orders, authorizations,
registrations, qualifications, designations, declarations or filings with any
governmental or banking authority on the part of Purchaser required in
connection with the consummation of the transactions contemplated in this
Agreement have been or shall have been obtained prior to and be effective as of
the Closing.

         4.3 INVESTMENT REPRESENTATIONS. Purchaser understands that the Shares
have not been registered under the Securities Act. Purchaser also understands
that the Shares are being offered and sold pursuant to an exemption from
registration contained in the Securities Act based in part upon Purchaser's
representations contained in the Agreement. Purchaser hereby represents and
warrants as follows:

                  (a) PURCHASER IS AN ACCREDITED INVESTOR. Purchaser represents
that Purchaser is an Accredited Investor within the meaning of Rule 501(a) of
Regulation D under the Securities Act.

                  (b) PURCHASER BEARS ECONOMIC RISK. Purchaser must bear the
economic risk of this investment indefinitely unless the Shares are registered
pursuant to the Securities Act, or an exemption from registration is available.
Purchaser understands that it has no registration rights with respect to the
Shares. Purchaser also understands that there is no assurance that any exemption
from registration under the Securities Act will be available and that, even if
available, such exemption may not allow Purchaser to transfer all or any portion
of the Shares under the circumstances, in the amounts or at the times Purchaser
might propose.

                  (c) ACQUISITION FOR OWN ACCOUNT. Purchaser is acquiring the
Shares for Purchaser's own account for investment only, and not with a view
towards their distribution within the meaning of the Securities Act.



                                       4.
<PAGE>   6

                  (d) PURCHASER CAN PROTECT ITS INTEREST. Purchaser represents
that by reason of its, or of its management's, business or financial experience,
Purchaser has the capacity to protect its own interests in connection with the
transactions contemplated in this Agreement. Purchaser is not a corporation,
trust or partnership specifically formed for the purpose of consummating these
transactions.

                  (e) COMPANY INFORMATION. Purchaser has had an opportunity to
discuss the Company's business, management and financial affairs with directors,
officers and management of the Company and has had the opportunity to review the
Company's operations and facilities. Purchaser has also had the opportunity to
ask questions of and receive answers from, the Company and its management
regarding the terms and conditions of this investment.

5.       LEGENDS.

Each certificate or other document evidencing any of the Shares or any Common
Stock issued upon conversion thereof shall be endorsed with the legends in the
form substantially as set forth in paragraphs (a) and (c) below, and each
certificate or other document evidencing the Shares, but not any such Common
Stock issued upon conversion of the Shares, shall be endorsed with the legend
substantially in the form set forth in paragraph (b) below, and Purchaser
covenants that, except to the extent such restrictions are waived by the
Company, Purchaser shall not transfer the Shares represented by any such
certificate without complying with restrictions on transfer described in the
legends endorsed on such certificate. Notwithstanding the foregoing, upon
registration of any Common Stock issued upon conversion of the Shares under the
Securities Act of 1933, the provisions of this Section 5 shall no longer apply
and the Company shall promptly exchange the certificates representing such
Common Stock with unlegended certificates.

                  (a)  The following legend under the Act:

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933 (THE "ACT"). THEY MAY NOT BE SOLD OR OFFERED FOR SALE
OR OTHERWISE DISTRIBUTED UNLESS THE SECURITIES ARE REGISTERED UNDER THE ACT OR
AN EXEMPTION THEREFROM IS AVAILABLE.

                  (b) The following legend:

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO RESTRICTIONS ON
TRANSFER AS PROVIDED IN THE CERTIFICATE OF DESIGNATION OF SERIES B PREFERRED
STOCK OF CERUS CORPORATION, A COPY OF WHICH MAY BE OBTAINED UPON WRITTEN REQUEST
FROM THE SECRETARY OF THE CORPORATION AT ITS PRINCIPAL OFFICE.

                  (c) Any legend imposed or required by applicable state
securities laws.



                                       5.
<PAGE>   7

6.       CONDITIONS TO CLOSING.

         6.1 CONDITIONS TO PURCHASER'S OBLIGATIONS AT THE CLOSING. Purchaser's
obligation to purchase the Shares identified in Section 1.1 of the Agreement at
each Closing are subject to the satisfaction, at or prior to each Closing, of
the following conditions:

                  (a) Representations and Warranties True; Performance of
Obligations. The representations and warranties made by the Company in Sections
3.1, 3.2, 3.3, 3.4, 3.6 and 3.8 hereof, shall be true and correct in all
material respects as of the Closing with the same force and effect as if they
had been made as of the Closing, and the Company shall have performed and
complied with all obligations and conditions herein required to be performed or
complied with by it on or prior to the Closing.

                  (b) Legal Investment. At the time of the Closing, the sale and
issuance of the Shares shall be legally permitted by all laws and regulations to
which Purchaser and the Company are subject.

                  (c) Consents, Permits and Waivers. The Company shall have
obtained any and all authorizations, approvals, consents, permits and waivers
necessary or appropriate for consummation of the transactions contemplated by
this Agreement (except for such as may be properly obtained subsequent to the
Closing, and such items shall be effective on and as of the Closing).

                  (d) Certificate of Good Standing. The Company shall have
obtained a Certificate of Good Standing from the Delaware Secretary of State
dated as of a recent date prior to the Closing.

                  (e) Opinion Letter. Purchaser shall have received from Cooley
Godward LLP, counsel to the Company, an opinion letter addressed to it, dated
the date of the Closing, in substantially the form attached hereto as Exhibit B.

                  (f) Proceedings and Documents. All corporate and other
proceedings in connection with the transactions contemplated at the Closing and
all documents and instruments incident to such transactions shall be reasonably
satisfactory in form and substance to counsel to Purchaser, and counsel to
Purchaser shall have received all such counterpart originals or certified or
other copies of such documents as they may reasonably request.

                  (g) Compliance Certificate. The Company shall have delivered
to Purchaser a Compliance Certificate, executed by the President and the Chief
Financial Officer of the Company, dated the Closing Date, to the effect that the
conditions specified in subparagraphs (a) through (f) of this Section 6.1 have
been satisfied.

                  (h) Registration Rights. The Company shall have obtained the
Requisite Approval as set forth in Section 7.4.

         6.2 CONDITIONS TO OBLIGATIONS OF THE COMPANY. The Company's obligation
to issue and sell the Shares at a Closing is subject to the satisfaction, on or
prior to the Closing, of the following conditions:



                                       6.
<PAGE>   8

                  (a) Representations and Warranties True. The representations
and warranties made by the Purchaser in Section 4 hereof shall be true and
correct in all material respects at the date of the Closing, with the same force
and effect as if they had been made on and as of said date.

                  (b) Performance of Obligations. Purchaser shall have performed
and complied with all agreements and conditions herein required to be performed
or complied with by Purchaser on or before the Closing.

7.       MISCELLANEOUS.

         7.1 GOVERNING LAW. This Agreement shall be governed in all respects by
the laws of the State of California.

         7.2 SURVIVAL. The representations, warranties, covenants and agreements
made herein shall survive any investigation made by Purchaser and the closing of
the transactions contemplated hereby. All statements as to factual matters
contained in any certificate or other instrument delivered by or on behalf of
the Company pursuant hereto in connection with the transactions contemplated
hereby shall be deemed to be representations and warranties by the Company
hereunder solely as of the date of such certificate or instrument, except as
expressly provided otherwise in such certificate or instrument. Sections 1.3 and
1.4 hereof shall survive each Closing.

         7.3 SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors and administrators of the
parties hereto and shall inure to the benefit of and be enforceable by each
person who shall be a holder of the Shares from time to time; provided, however,
that prior to the receipt by the Company of adequate written notice of the
transfer of any Shares specifying the full name and address of the transferee,
the Company may deem and treat the person listed as the holder of such Shares in
its records as the absolute owner and holder of such Shares for all purposes,
the payment of any dividends or any redemption price.

         7.4 REGISTRATION RIGHTS. Subject to the approval of the requisite
holders of "Registrable Securities" (the "Requisite Approval") under the Amended
and Restated Investors' Rights Agreement, dated as of April 1, 1996, between the
Company and the investors thereto (the "Rights Agreement"), the Common Stock
issuable upon conversion of the Shares shall be Registrable Securities as
defined in Section 1.3 of the Rights Agreement. Subject to the Requisite
Approval, by signing this Agreement, Purchaser agrees to be bound by the Rights
Agreement as a party thereto. Cerus will use its best efforts to obtain such
approval on or before July 15, 1998. Baxter, as a holder of Registrable
Securities, hereby consents to such action, and agrees to execute such other
instruments as shall be appropriate to evidence such approval.

         7.5 REDEMPTION OF SHARES. If the Company elects to redeem the Shares,
as provided for in the Certificate of Designation for the Series B Preferred
Stock and indebtedness is then owing from Purchaser to the Company, the Company
and Purchaser will agree to consider and discuss whether to permit the Company
to pay all or a portion of the redemption price through cancellation of
indebtedness. If the parties can not agree to such arrangement, the redemption
price will be paid in cash.



                                       7.
<PAGE>   9

         7.6 ENTIRE AGREEMENT. This Agreement, the Rights Agreement and the
other documents delivered pursuant hereto and thereto constitute the full and
entire understanding and agreement between the parties with regard to the
subjects hereof and no party shall be liable or bound to any other in any manner
by any representations, warranties, covenants and agreements except as
specifically set forth herein. Nothing in this Agreement, express or implied, is
intended to confer upon any party, other than the parties hereto, and their
respective successors and assigns, any rights, remedies, obligations or
liabilities under or by reason of this Agreement, except as expressly provided
herein.

         7.7 SEPARABILITY. In case any provision of the Agreement shall be
invalid, illegal or unenforceable, such provision shall, to the extent
practicable, be modified so as to make it valid, legal and enforceable and to
maintain as nearly as practicable the intent of the parties, and the validity,
legality and enforceability of the remaining provisions shall not in any way be
affected or impaired thereby.

         7.8      AMENDMENT AND WAIVER.

                  (a) This Agreement may be amended or modified only upon the 
written consent of the parties hereto.

                  (b) The obligations of the Company and the rights of the
holder of the Shares under this Agreement may be waived only with the written
consent of the parties hereto.

                  (c) Except to the extent provided in this Section 7.8, neither
this Agreement nor any provision hereof may be changed, waived, discharged or
terminated, except by a statement in writing signed by the party against which
enforcement of the change, waiver, discharge or termination is sought.

                  (d) Any amendment or waiver effected in accordance with this
Section 7.8 shall be binding upon any future holder of some or all of the
Shares.

         7.9 DELAYS OR OMISSIONS. It is agreed that no delay or omission to
exercise any right, power or remedy accruing to Purchaser or the Company, upon
any breach, default or noncompliance of the Company or Purchaser, as the case
may be, under this Agreement or the Certificate of Incorporation shall impair
any such right, power or remedy, nor shall it be construed to be a waiver of any
such breach, default or noncompliance, or any acquiescence therein, or of or in
any similar breach, default or noncompliance thereafter occurring. It is further
agreed that any waiver, permit, consent or approval of any kind or character on
either of the Company's or Purchaser's part of any breach, default or
noncompliance under this Agreement or the Certificate of Incorporation or any
waiver on either of the Company's or Purchaser's part of any provisions or
conditions of this Agreement must be in writing and shall be effective only to
the extent specifically set forth in such writing. All remedies under this
Agreement, the Certificate of Incorporation or Bylaws, or otherwise afforded to
the Company or Purchaser, shall be cumulative and not alternative. Upon receipt
of a Notice in compliance with Section 1.1 hereof, Purchaser's obligation to
purchase the Shares as specified therein and to pay the purchase price therefor
determined in accordance with Section 1.1 hereof, shall be subject only to the
conditions set forth in Section 6.1 of this Agreement. Upon satisfaction of the
conditions set 



                                       8.
<PAGE>   10

forth in Section 6.1, Purchaser's obligation to purchase the Shares and pay the
purchase price therefor in accordance with Section 1.1, shall become absolute
and unconditional.

         7.10 NOTICES. Except as otherwise specified in Section 1.1 hereof with
respect to a Notice, all notices and other communications required or permitted
hereunder shall be in writing and shall be deemed effectively given and received
(a) upon personal delivery, (b) on the fifth day following mailing sent by
registered or certified mail, return receipt requested, postage prepaid, (c)
upon confirmed delivery by means of a nationally recognized overnight courier
service or (d) upon transmission of facsimile (with telephonic notice)
addressed: (i) if to Purchaser, at Purchaser's address as set forth on the
Company's records, or at such other address as Purchaser shall have furnished to
the Company in writing or (ii) if to the Company, at its address as set forth at
the end of this Agreement, or at such other address as the Company shall have
furnished to Purchaser in writing.

         7.11 EXPENSES. The Company shall pay all costs and expenses that it
incurs with respect to the negotiation, execution, delivery and performance of
the Agreement, and Purchaser shall pay all costs and expenses that it incurs
with respect to the negotiation, execution, delivery and performance of this
Agreement.

         7.12 ATTORNEYS' FEES. If legal action is brought to enforce or
interpret this Agreement, the prevailing party shall be entitled to recover its
reasonable attorneys' fees and legal costs in connection therewith.

         7.13 TITLES AND SUBTITLES. The titles of the paragraphs and
subparagraphs of the Agreement are for convenience of reference only and are not
to be considered in construing this Agreement.

         7.14 COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one instrument.

         7.15 BROKER'S FEES. Each party hereto represents and warrants that no
agent, broker, investment banker, person or firm acting on behalf of or under
the authority of such party hereto is or will be entitled to any broker's or
finder's fee or any other commission directly or indirectly in connection with
the transactions contemplated herein. Each party hereto further agrees to
indemnify each other party for any claims, losses or expenses incurred by such
other party as a result of the representation in this Section 7.15 being untrue.

         7.16 SUBSEQUENT CONSENTS, PERMITS AND WAIVERS. The Company shall obtain
promptly after the Closing all authorizations, approvals, consents, permits and
waivers that are necessary or applicable for consummation of the transactions
contemplated by this Agreement and that were not obtained prior to the Closing
because they may be properly obtained subsequent to the Closing.

         7.17 CONCERNING SENIOR CLASS OR SERIES. If, prior to the issuance and
sale of the Series B Preferred pursuant to this Agreement, the Company issues or
agrees to issue any other class or series of stock that would rank senior to the
Series B Preferred, then Purchaser's obligation to purchase Series B Preferred
hereunder shall terminate.



                                       9.
<PAGE>   11


IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the
date set forth in the first paragraph hereof.

COMPANY:

CERUS CORPORATION
2525 Stanwell Drive
Concord, CA  94520



By:_______________________________
Stephen T. Isaacs
President

PURCHASER:

BAXTER HEALTHCARE CORPORATION
One Baxter Parkway
Deerfield, Illinois  60015



By:_______________________________
         (Signature)

Name:_____________________________

Its:______________________________


                                       1.

<PAGE>   12


                                    EXHIBIT A

          CERTIFICATE OF DESIGNATION OF SERIES B _____ PREFERRED STOCK



                                       1.

<PAGE>   13


                                    EXHIBIT B

                                 FORM OF OPINION



________________________ , 199_



Baxter Healthcare Corporation
One Baxter Parkway
Deerfield, IL  60015

RE:      CERUS CORPORATION

Ladies and Gentlemen:

We have acted as counsel to Cerus Corporation, a Delaware corporation (the
"Company"), in connection with the issuance and sale to you of the Shares (as
defined in the Series B Preferred Stock Purchase Agreement between you and the
Company, dated as of June 30, 1998 (the "Purchase Agreement"), such issuance and
sale to take place pursuant to the terms and conditions of the Purchase
Agreement. We are rendering this opinion pursuant to Section 6.1(e) of the
Purchase Agreement. Except as otherwise defined herein, capitalized terms used
but not defined herein have the respective meanings given to them in the
Purchase Agreement.

In connection with this opinion, we have examined and relied upon the
representations and warranties as to factual matters contained in and made
pursuant to the Agreement by the various parties and originals or copies
certified to our satisfaction, of such records, documents, certificates,
opinions, memoranda and other instruments as in our judgment are necessary or
appropriate to enable us to render the opinion expressed below. Where we render
an opinion "to the best of our knowledge" or concerning an item "known to us" or
our opinion otherwise refers to our knowledge, it is based solely upon (i) an
inquiry of attorneys within this firm who perform legal services for the
Company, (ii) receipt of a certificate executed by an officer of the Company
covering such matters, and (iii) such other investigation, if any, that we
specifically set forth herein.

In rendering this opinion, we have assumed the genuineness and authenticity of
all signatures on original documents; the authenticity of all documents
submitted to us as originals; the conformity to originals of all documents
submitted to us as copies; the accuracy, completeness and authenticity of
certificates of public officials; and the due authorization, execution and
delivery of all documents (except the due authorization, execution and delivery
by the Company of the Purchase Agreement) where authorization, execution and
delivery are prerequisites to the effectiveness of such documents. We have also
assumed that all individuals executing and delivering documents in their
individual capacities had the legal capacity to so execute and deliver; that you
have received all documents you were to receive under the Purchase Agreement;
that the Purchase Agreement is an obligation binding upon you; that you have
filed any required California 

<PAGE>   14

Baxter Health Corporation
__________________, 199_Baxter Health Corporation
Page 2

franchise or income tax returns and have paid any required California franchise
or income taxes; and that there are no extrinsic agreements or understandings
among the parties to the Purchase Agreement that would modify or interpret the
terms of the Purchase Agreement or the respective rights or obligations of the
parties thereunder.

Our opinion is expressed only with respect to the federal laws of the United
States of America, the laws of the State of California and the General
Corporation Law of the State of Delaware. We express no opinion as to whether
the laws of any particular jurisdiction apply, and no opinion to the extent that
the laws of any jurisdiction other than those identified above are applicable to
the subject matter hereof. We are not rendering any opinion as to compliance
with any antifraud law, rule or regulation relating to securities, or to the
sale or issuance thereof.

With respect to the opinion in paragraph 3 hereof regarding issued and
outstanding capital stock of the Company, we have examined and have relied
solely on a certificate furnished by the Company's transfer agent, Norwest Bank
Minnesota, N.A., a copy of which has been made available to you. We have
undertaken no independent verification with respect thereto.

With regard to our opinion in paragraph 4 below with respect to material
defaults under any of the Material Agreements (as defined below), we have relied
solely upon (i) inquiries of officers of the Company, (ii) a list supplied to us
by the Company of material agreements to which the Company is a party, or by
which it is bound (the "Material Agreements"), and (iii) an examination of the
items on the aforementioned list; we have made no further investigation.

On the basis of the foregoing, in reliance thereon and with the foregoing
qualifications, we are of the opinion that:

         1. The Company has been duly incorporated and is a validly existing
corporation in good standing under the laws of the State of Delaware. The
Company has the requisite corporate power to own its property and assets and to
conduct its business as it is currently being conducted.

         2. The Purchase Agreement has been duly and validly authorized,
executed and delivered by the Company and constitutes a legal, valid and binding
agreement of the Company enforceable against the Company in accordance with its
terms, except as enforcement may be limited by applicable bankruptcy,
insolvency, reorganization, arrangement with creditors, moratorium or other
similar laws affecting creditors' rights, and subject to general equity
principles and to limitations on availability of equitable relief, including
specific performance.

         3. The Company's authorized capital stock consists of (a)
_____________________ shares of Common Stock, of which _________________________
(_________) are issued and outstanding, and (b) _________________________ shares
of Preferred Stock, of which five thousand (5,000) shares have been designated
Series A Preferred Stock, 5,000 shares of which (excluding the Shares to be
issued at Closing) are issued and outstanding. The outstanding shares of Common
Stock have been duly authorized, validly issued and are fully paid and
nonassessable. The rights, preferences and privileges of the Series B Preferred
Stock are as stated in the Certificate of Designation of Series B Preferred
Stock. The Shares have been duly and validly authorized, and upon issuance and
delivery against payment therefor in accordance 


                                       2.

<PAGE>   15

Baxter Health Corporation
__________________, 199_Baxter Health Corporation
Page 3


with the Purchase Agreement will be validly issued, outstanding, fully paid and
nonassessable. The Shares of Common Stock issuable upon conversion of the Shares
have been duly authorized, and upon issuance and delivery upon conversion
thereof in accordance with the terms of the Shares, will be validly issued,
outstanding, fully paid and nonassessable.

         4. The execution, delivery and performance of the Purchase Agreement by
the Company and the offer, issuance and sale of the Shares pursuant thereto (a)
do not constitute a material default under, and do not result in a lien or other
encumbrance on the property of the Company pursuant to, the provisions of any of
the Material Agreements, (b) do not violate any provision of the Company's
Certificate of Incorporation or Bylaws, and (c) do not violate or contravene any
governmental statute, rule or regulation applicable to the Company.

         5. To the best of our knowledge, there is no action, suit, proceeding
or investigation pending or overtly threatened against the Company before any
domestic or foreign court or administrative agency that questions the validity
of the Purchase Agreement.

         6. All consents, approvals, authorizations or orders of, and filings,
registrations and qualifications with any regulatory authority or governmental
body in the United States required for the consummation by the Company of the
offer, issuance and sale of the Shares contemplated by the Purchase Agreement
have been made or obtained.

This opinion is intended solely for your benefit and is not to be made available
to or be relied upon by any other person, firm, or entity without our prior
written consent.

Very truly yours,

COOLEY GODWARD LLP



By:____________________________
         Howard G. Ervin


                                       3.

<PAGE>   16

                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                   PAGE
<S>      <C>      <C>                                                              <C>


1.       AGREEMENT TO SELL AND PURCHASE...............................................1

         1.1      Sale and Purchase of the Shares.....................................1

         1.2      Authorization of Shares.............................................1

         1.3      Sale Exclusively To Purchaser.......................................2

         1.4      Premium.............................................................2

2.       CLOSING, DELIVERY AND PAYMENT................................................2

3.       REPRESENTATIONS AND WARRANTIES OF THE COMPANY................................2

         3.1      Organization, Good Standing and Qualification.......................2

         3.2      Authorization; Binding Obligations..................................2

         3.3      Compliance With Other Instruments...................................3

         3.4      Securities Exemption................................................3

         3.5      Subsidiaries........................................................3

         3.6      Valid Issuance of Shares............................................3

         3.7      Litigation, Etc.....................................................3

         3.8      Governmental Consents...............................................3

4.       REPRESENTATIONS AND WARRANTIES OF PURCHASER..................................4

         4.1      Requisite Power and Authority.......................................4

         4.2      Consents............................................................4

         4.3      Investment Representations..........................................4

                  (a)      Purchaser is an Accredited Investor........................4

                  (b)      Purchaser Bears Economic Risk..............................4

                  (c)      Acquisition for Own Account................................4

                  (d)      Purchaser Can Protect its Interest.........................5

                  (e)      Company Information........................................5

5.       LEGENDS......................................................................5

6.       CONDITIONS TO CLOSING........................................................6

         6.1      Conditions to Purchaser's Obligations at the Closing................6

         6.2      Conditions to Obligations of the Company............................6

</TABLE>


                                       i.

<PAGE>   17

                                TABLE OF CONTENTS
                                   (CONTINUED)

<TABLE>
<CAPTION>
                                                                                   PAGE
<S>      <C>      <C>                                                              <C>
7.       MISCELLANEOUS................................................................7

         7.1      Governing Law.......................................................7

         7.2      Survival............................................................7

         7.3      Successors and Assigns..............................................7

         7.4      Registration Rights.................................................7

         7.5      Redemption of Shares................................................7

         7.6      Entire Agreement....................................................8

         7.7      Separability........................................................8

         7.8      Amendment and Waiver................................................8

         7.9      Delays or Omissions.................................................8

         7.10     Notices.............................................................9

         7.11     Expenses............................................................9

         7.12     Attorneys' Fees.....................................................9

         7.13     Titles and Subtitles................................................9

         7.14     Counterparts........................................................9

         7.15     Broker's Fees.......................................................9

         7.16     Subsequent Consents, Permits and Waivers............................9

         7.17     Concerning Senior Class or Series...................................9

</TABLE>

                                      ii.


<PAGE>   1
                                                                   EXHIBIT 10.30

                             MEMORANDUM OF AGREEMENT


        This Memorandum of Agreement confirms that Cerus has agreed to buy and
Baxter has agreed to sell a 5.3% share in Revenue Sharing Payment participation
of the platelet project. The points of agreement are set forth below as an
Amendment to the Development, Manufacturing and Marketing Agreement dated
December 10, 1993 (the "Platelet Agreement"). Capitalized terms not otherwise
defined in this Memorandum of Agreement have the meaning ascribed to them in the
Platelet Agreement.

        1. Under this agreement, Section 7.1 of the Platelet Agreement regarding
the Revenue Sharing Payments is amended to provide that the quarterly payments
by Baxter to Cerus will be 33.5% of the Premium during the relevant calendar
quarter, rather than 26% of the Premium as originally agreed and amended to
28.2% in a Memorandum of Agreement dated January 3, 1997 (the "First Platelet
Amendment").

        Section 7.2 of the Platelet Agreement regarding "Exception to Revenue
Sharing Payments of 7.1" is amended to provide that Cerus will receive
additional Revenue Sharing Payments beyond those set forth in Section 7.2 equal
to 7.5% of the Premium, consisting of the 5.3% described above and the 2.2%
described in the First Platelet Amendment, and the $8.50 and $20.00 limitations
set forth in Section 7.2 shall not limit such additional amounts of Revenue
Sharing Payment.

        2. In consideration for Cerus' increase of 5.3% in Revenue Sharing
Payment participation, as described in paragraph 1 above, Cerus will pay to
Baxter Eight Million Three Hundred Thousand Dollars ($8,300,000) on June 30,
1999; provided, however that such payment date may be extended for an additional
period, not exceeding twelve months, if such extension is necessary or advisable
in respect of Cerus' then cash reserves and cash flow requirements. This
agreement does not change the other aspects of the Platelet Agreement and the
parties reaffirm their intention of each firm to continue funding 50% of the
research and development expense, subject to the provisions of the Second
Amendment to that Agreement, being entered into concurrently herewith.


<PAGE>   2
        Please indicate your concurrence that this memorandum accurately
summarizes our agreement by signing and returning a copy to me. This agreement
will be effective June 30,1998.

CERUS CORPORATION                           BAXTER HEALTHCARE CORPORATION



By /s/ Stephen T. Isaacs                    By /s/ Roberto Perez
   -------------------------------             -------------------------------
Stephen T. Isaacs                           Roberto Perez, President
Chief Executive Officer                     Fenwal Division

<PAGE>   1
                                                                   EXHIBIT 10.31

                 SECOND AMENDMENT TO DEVELOPMENT, MANUFACTURING
                             AND MARKETING AGREEMENT


        THIS AMENDMENT ("Amendment") amends the Development, Manufacturing and
Marketing Agreement, dated as of December 10, 1993 (the "Agreement") between
BAXTER HEALTHCARE CORPORATION, a Delaware corporation ("Baxter") with principal
offices at One Baxter Parkway, Deerfield, Illinois 60015, and CERUS CORPORATION,
a Delaware corporation ("Cerus"), successor in interest to STERITECH, INC., a
California corporation, with principal offices at 2525 Stanwell Drive, Concord,
California 94520. The Amendment is effective as of June 30, 1998 ("Second
Amendment Effective Date").

1.      BACKGROUND.

        1.1 Cerus and Baxter previously entered into a Memorandum of Agreement
and separate Memorandum "Re: 1997 Project Budgets," each dated as of January 3,
1997 (collectively, the "First Amendment"), which amended the Agreement.

        1.2 Cerus and Baxter have agreed to certain other modifications to the
Agreement as set forth herein.

2.      DEFINITION OF TERMS.

        The words appearing in capitalized form throughout this Amendment shall
have the meanings assigned to them in the Agreement. All references in the
Agreement to Steritech are deemed to be references to Cerus, effective as of the
date of the merger of Steritech into Cerus (January 31, 1997).

3.      EXPENDITURES.

        A Section 3.8.3 shall be added to the Agreement to read as follows:

        "3.8.3 Notwithstanding the foregoing provisions of this Section 3.8, for
        the period commencing April 1, 1998, Cerus will fund Baxter's share of
        the costs and expenses of the Cooperative Development in the amount of
        five million dollars ($5,000,000), after which all costs and expenses of
        the Cooperative Development Work shall be borne equally by Baxter and
        Cerus. The reconciliation of expenditures provided for in Sections 3.12
        and 3.13, shall be subject to the preceding sentence."

4.      MILESTONE PAYMENTS.

        A Section 4.3 shall be added to the Agreement to read as follows:

        "4.3 APPROVAL PAYMENT. Baxter shall pay to Cerus the amount of five
        million dollars ($5,000,000) promptly upon receipt from the FDA of a new
        drug approval (NDA) or pre-market approval (PMA) or equivalent, or
        receipt of a CE Mark Approval in Europe, for the System."


                                       1.


<PAGE>   2
5.      MARKETING.

        Section 6.3 of the Agreement shall be deleted, and a new Section 6.3
will be added to the Agreement to read as follows:

        "6.3 MEETINGS CONCERNING MARKETING. The Management Board shall meet from
        time-to-time to discuss and approve marketing strategies in order to
        optimize customer acceptance and effective promotion of the System. All
        final plans and strategies regarding System marketing, distribution and
        pricing shall be established by the Management Board reasonably and in
        good faith. Baxter shall follow the plans and strategies established by
        the Management Board. The Management Board will review the marketing
        plans and strategies, including pricing, from time to time in the light
        of market conditions. Day-to-day marketing and sales decisions will not
        be made by the Management Board; Baxter will be responsible to make
        day-to-day marketing and sales decisions using its best efforts to
        maximize Net Sales in the interest of both parties."

6.      TERMINATION PAYMENT.

        A Section 13.4 and Section 13.5 shall be added to the Agreement to read
        as follows:

        "13.4 TERMINATION PAYMENT. In the event of cessation of the Cooperative
        Development Work for any reason whatsoever, whether based on either
        party's unilateral cessation of participation or a mutual decision to
        cease participation, or in the event this Agreement is terminated for
        any reason whatsoever, either by one party or by mutual agreement,
        Baxter will promptly pay to Cerus a termination payment in the amount of
        five million dollars ($5,000,000), or such lesser amount of Baxter's
        share of costs and expenses for the Cooperative Development Work funded
        by Cerus pursuant to Section 3.8.3 to the date of cessation or
        termination. Such payment shall be in addition to any other payments
        required of Baxter as provided elsewhere in this Agreement."

        "13.5 RESTRICTION ON UNILATERAL CESSATION. Notwithstanding Section 13.1,
        neither party shall unilaterally cease participation in the Cooperative
        Development Work until Cerus has funded the amount set forth in Section
        3.8.3."

7.      EFFECTIVENESS.

        Notwithstanding any other provision hereof, the amendments to Sections
3.8.3 and 4.3 set forth above shall be effective only upon the Closing, as
defined in the Series A Preferred Stock Purchase Agreement of even date herewith
between Baxter and Cerus.

8.      CONCERNING CARRY-OVER OBLIGATION.

        Cerus acknowledges and agrees that Baxter has no obligation relating to
carry-over of expenses owed by Baxter to Cerus pursuant to the First Amendment.


                                       2.


<PAGE>   3
        IN WITNESS WHEREOF, this Amendment is signed by duly authorized
representatives of each party as of the Second Amendment Effective Date.


CERUS CORPORATION                     BAXTER HEALTHCARE CORPORATION



By:     /s/ Stephen T. Isaacs         By:    /s/ Roberto Perez
        -------------------------            -------------------------------
        STEPHEN T. ISAACS                    ROBERTO PEREZ
Title:  President and Chief           Title:  President, Baxter Fenwal Division
        Executive Officer




<PAGE>   1
                                                                   EXHIBIT 10.32


                                           .***TEXT OMITTED AND FILED SEPARATELY
                                                CONFIDENTIAL TREATMENT REQUESTED
                                           UNDER 17 C.F.R. SECTION 200.80(B)(4),
                                                            200.83 AND 240.24B-2


                           DEVELOPMENT, MANUFACTURING
                                       AND
                               MARKETING AGREEMENT


                                     BETWEEN
                          BAXTER HEALTHCARE CORPORATION
                                       AND
                                CERUS CORPORATION



                                  APRIL 1, 1996

                             AS AMENDED AND RESTATED

                                  JUNE 30, 1998


<PAGE>   2
                                TABLE OF CONTENTS


<TABLE>
<CAPTION>
                                                                                              PAGE
                                                                                              ----
<S>                                                                                           <C>
1.      BACKGROUND..........................................................................    1

2.      DEFINITION OF TERMS.................................................................    1

3.      COOPERATIVE DEVELOPMENT WORK........................................................   11

        3.1    Period; Objective............................................................   11

        3.2    Management Board.............................................................   11

               (a)    Constitution..........................................................   11

               (b)    Project Committees....................................................   11

               (c)    Patent Committee......................................................   12

               (d)    Voting................................................................   12

               (e)    Disputes..............................................................   13
                                                                                               
        3.3    Review Of Budget, Benchmarks; Approved Projects..............................   13
                                                                                               
               (a)    The Red Cell Project..................................................   14
                                                                                               
               (b)    The S59 FFP Project...................................................   15
                                                                                               
               (c)    Other Projects........................................................   16
                                                                                               
        3.4    Exchange Of Information......................................................   16
                                                                                               
        3.5    Cost Sharing.................................................................   16
                                                                                               
        3.6    Testing And Regulatory Expenses..............................................   17
                                                                                               
               (a)    Testing Expenses......................................................   17
                                                                                               
               (b)    Regulatory Expenses...................................................   17
                                                                                               
        3.7    Budget Contingencies.........................................................   17
                                                                                               
               (a)    Exceeding Initial Budget..............................................   17
                                                                                               
               (b)    Reconciliation Of Expenditures........................................   17
                                                                                               
        3.8    New Technologies.............................................................   18
                                                                                               
        3.9    Coordination and Facilitation of Communications..............................   19
                                                                                               
4.      EQUITY PURCHASE.....................................................................   20
                                                                                               
        4.1    Baxter Purchase Of Equity In Cerus...........................................   20
                                                                                               
        4.2    Standstill By Baxter.........................................................   22
                                                                                               
5.      SUPPLY OF CERUS COMPOUND AND SYSTEM MANUFACTURING...................................   24
                                                                                               
        5.1    Cerus Responsibilities.......................................................   24
</TABLE>


<PAGE>   3

                                TABLE OF CONTENTS
                                   (CONTINUED)
<TABLE>
<CAPTION>
                                                                                              PAGE
                                                                                              ----
<S>                                                                                           <C>
        5.2    Baxter Responsibilities......................................................   24
                                                                                               
        5.3    Instrument Production........................................................   25
                                                                                               
        5.4    System Specifications........................................................   25
                                                                                               
        5.5    Cerus Specifications.........................................................   25
                                                                                               
        5.6    Source Of Supply.............................................................   25
                                                                                               
        5.7    Failure Of Cerus To Meet Baxter Requirements.................................   25
                                                                                               
        5.8    System Improvements..........................................................   25
                                                                                               
6.      MARKETING AND DISTRIBUTION RIGHTS:  EXCLUSIVE DISTRIBUTION RIGHTS...................   26
                                                                                               
        6.1    Commercialization............................................................   26
                                                                                               
        6.2    Meetings Concerning Marketing................................................   26
                                                                                               
        6.3    Exclusive Relationship.......................................................   26
                                                                                               
        6.4    Competing Products...........................................................   26
                                                                                               
        6.5    Commencement, Cessation Of Marketing.........................................   27
                                                                                               
        6.6    Achievement Of Market Share..................................................   27
                                                                                               
        6.7    Supply Of Baxter Goods.......................................................   28
                                                                                               
        6.8    Requalification..............................................................   28
                                                                                               
        6.9    Management Board Access To And Review Of Marketing And Distribution             
               Information..................................................................   28
                                                                                               
        6.10   Baxter Termination of Distribution for S59 FFP Systems.......................   28
                                                                                               
        6.11   Baxter Termination of Supply of Goods for S59 FFP Systems....................   29
                                                                                               
        6.12   Cerus Termination of Baxter Manufacturing Rights for S59 FFP Systems.........   29
                                                                                               
        6.13   Cerus Termination of Distribution Rights for S59 FFP Systems.................   29
                                                                                               
7.      REVENUE SHARING.....................................................................   30
                                                                                               
        7.1    Revenue Sharing Payments.....................................................   30
                                                                                               
        7.2    Baxter Sourcing Cerus Compounds..............................................   30
                                                                                               
        7.3    Cerus As Seller Of Systems...................................................   30
                                                                                               
        7.4    Licensing Of Rights Arising Under This Agreement.............................   30
                                                                                               
        7.5    Distributor Sales............................................................   31
                                                                                               
8.      PATENTS, KNOW-HOW, LICENSE GRANTS...................................................   31
                                                                                               
        8.1    Cerus Sole Ownership.........................................................   31
</TABLE>


<PAGE>   4
                                TABLE OF CONTENTS
                                   (CONTINUED)
<TABLE>
<CAPTION>
                                                                                              PAGE
                                                                                              ----
<S>                                                                                           <C>
        8.2    Baxter Sole Ownership........................................................   31
                                                                                               
        8.3    Joint Ownership..............................................................   31
                                                                                               
        8.4    License......................................................................   32
                                                                                               
        8.5    Cerus Rights.................................................................   33
                                                                                               
        8.6    Cross-License As To Instruments And Compound Removal Devices;                   
               Exploitation Of Joint Inventions Outside The Field...........................   33
                                                                                               
        8.7    Excluded Products............................................................   34
                                                                                               
        8.8    Notice Of Sole Rights........................................................   34
                                                                                               
        8.9    Other Agreements.............................................................   34
                                                                                               
        8.10   Regulatory Files.............................................................   34
                                                                                               
        8.11   Rights Under Government-Sponsored Research...................................   35
                                                                                               
9.      PROSECUTION OF PATENT RIGHTS........................................................   35
                                                                                               
        9.1    Cerus Patents................................................................   35
                                                                                               
        9.2    Baxter Patents...............................................................   35
                                                                                               
        9.3    Joint Patents................................................................   35
                                                                                               
        9.4    Prior Art; Review And Comment................................................   35
                                                                                               
        9.5    Project Patents; Licensing Payments to Third Parties.........................   35
                                                                                               
        9.6    Patent Expenses..............................................................   36
                                                                                               
        9.7    Election Not To Pay Expenses.................................................   36
                                                                                               
10.     TRADEMARKS..........................................................................   37
                                                                                               
        10.1   Baxter Trademarks............................................................   37
                                                                                               
        10.2   Cerus Trademarks.............................................................   37
                                                                                               
11.     CONFIDENTIAL INFORMATION............................................................   37
                                                                                               
        11.1   Confidentiality Agreement....................................................   37
                                                                                               
        11.2   Use Of Consultants...........................................................   37
                                                                                               
12.     CESSATION OF COOPERATIVE DEVELOPMENT WORK...........................................   37
                                                                                               
        12.1   Cessation....................................................................   37
                                                                                               
        12.2   Cessation Payment............................................................   38
                                                                                               
        12.3   Section 12 Not Applicable to S59 FFP.........................................   39
                                                                                               
13.     REPORTS.............................................................................   39
</TABLE>


<PAGE>   5
                                TABLE OF CONTENTS
                                   (CONTINUED)
<TABLE>
<CAPTION>
                                                                                              PAGE
                                                                                              ----
<S>                                                                                           <C>
        13.1   Quarterly Sales Reports......................................................   39
                                                                                               
        13.2   Cost Of Goods/Base Revenue...................................................   39
                                                                                               
14.     BOOKS AND RECORDS...................................................................   39
                                                                                               
        14.1   Records......................................................................   39
                                                                                               
        14.2   Retention....................................................................   40

        14.3   Interest.....................................................................   40
                                                                                               
15.     TERM................................................................................   40
                                                                                               
16.     BREACH..............................................................................   40
                                                                                               
        16.1   Material Breach..............................................................   40
                                                                                               
        16.2   Rights On Termination........................................................   40
                                                                                               
17.     REPRESENTATIONS AND INDEMNITIES.....................................................   41
                                                                                               
        17.1   Cerus Representations........................................................   41
                                                                                               
        17.2   Cerus Indemnification -- Representations And Warranties......................   41
                                                                                               
        17.3   Cerus Indemnification -- Products............................................   41
                                                                                               
        17.4   Insurance....................................................................   42
                                                                                               
        17.5   Baxter Representations.......................................................   42
                                                                                               
        17.6   Baxter Indemnification - Representations And Warranties......................   42
                                                                                               
        17.7   Baxter Indemnification - Products............................................   43
                                                                                               
        17.8   Baxter Insurance.............................................................   43
                                                                                               
18.     INFRINGEMENT........................................................................   43
                                                                                               
        18.1   Defense Of Third Party Infringement Suits....................................   43
                                                                                               
        18.2   Suits For Infringement By Others.............................................   43
                                                                                               
19.     PREFERRED STOCK PURCHASE............................................................   44
                                                                                               
20.     GENERAL.............................................................................   44
                                                                                               
        20.1   Entire Agreement.............................................................   44
                                                                                               
        20.2   Relationship Of Parties......................................................   44
                                                                                               
        20.3   Senior Baxter Contact........................................................   44
                                                                                               
        20.4   Senior Cerus Contact.........................................................   44
                                                                                               
        20.5   Severability.................................................................   44
                                                                                               
        20.6   Force Majeure................................................................   45
</TABLE>


<PAGE>   6
                                TABLE OF CONTENTS
                                   (CONTINUED)
<TABLE>
<CAPTION>
                                                                                              PAGE
                                                                                              ----
<S>                                                                                           <C>
        20.7   Notices......................................................................   45
                                                                                               
        20.8   Binding......................................................................   45
                                                                                               
        20.9   Governing Law................................................................   46
                                                                                               
        20.10  Venue........................................................................   46
                                                                                               
        20.11  Disbursements................................................................   46
                                                                                               
        20.12  Publicity....................................................................   46
                                                                                               
        20.13  Survival.....................................................................   46
</TABLE>


<PAGE>   7
                           DEVELOPMENT, MANUFACTURING
                             AND MARKETING AGREEMENT


        THIS AGREEMENT ("Agreement") between BAXTER HEALTHCARE CORPORATION, a
Delaware corporation ("BHC") with principal offices at One Baxter Parkway,
Deerfield, Illinois 60015, and CERUS CORPORATION, a Delaware corporation,
successor in interest to STERITECH, INC., a California corporation, with
principal offices at 2525 Stanwell Drive, Concord, California 94520, is
effective as of the 1st day of April, 1996 ("Effective Date") and is amended and
restated effective as of June 30, 1998 (the "First Amendment Effective Date").

1.      BACKGROUND.

        1.1 Cerus has substantial knowledge and expertise in the area of
inactivation of pathogens for the decontamination of blood products. Baxter has
substantial knowledge and expertise in the research, development, manufacture
and distribution of healthcare products including those relating to the
collection, preservation, processing, manipulation, storage and treatment of
blood and blood components.

        1.2 The parties are interested in the development and commercialization
of products and/or systems which provide a customer with instrumentation,
disposables and compounds for use in ex-vivo inactivation of pathogens for the
decontamination of human blood cells and human blood components intended for
human use.


2.      DEFINITION OF TERMS.

        The words appearing in capitalized form throughout this Agreement shall
have the meanings assigned to them in this Section 2.

        APPROVED DISTRIBUTOR means any company, other than a company (or any of
its affiliates) that manufactures blood collection products or any distributor
of blood collection products identified in a letter from Baxter to Cerus dated
the Effective Date. For the purposes of this definition, an "affiliate" of a
company shall mean an entity controlling, controlled by, or under common control
with such company. "Control" for the purposes of this definition shall mean
fifty percent (50%) ownership.

        APPROVED PROJECT FIELD means (a) that subset of the Field comprising
solely the ex vivo inactivation of pathogens for decontamination of (i) human
red blood cells through use of ALE compounds and (ii) FFP through use of
psoralens, in each case of clause (i) and (ii) otherwise meeting the limitations
set forth in the definition of the Field, and (b) each such other subset of the
Field as shall become the subject of a Project under this Agreement pursuant to
Section 3.8 hereof.

        ALE means anchor linker effector, as defined in that certain letter
dated March 14, 1996 from Kathryn P. Wilke of Cerus to Joseph B. Barrett of
Baxter.

        BASE REVENUE means for any Integrated Inactivation Set as of any
measurement date the average net sales price (computed using the same
adjustments as provided in paragraphs (a) and (b) of the definition of NET
SALES) of a comparable set without an Inactivation Package ("Base 


                                       1.


<PAGE>   8
Set") during the three full calendar months preceding such date, and in the case
of each new Integrated Inactivation Set, during the three full months preceding
the first sale of such Integrated Inactivation Set ("Initial Base Revenue").
Base Revenue shall be adjusted, with respect to the sales of each Integrated
Inactivation Set in each quarter commencing with the first full calendar quarter
after its first sale, to

               (a) an amount equal to the average net sales price (computed
using the same adjustments as provided in paragraphs (a) and (b) of the
definition of NET SALES) of a comparable Base Set during three full calendar
months preceding the first day of such calendar quarter, if there exists
throughout such period a large blood collection market for such comparable Base
Set, or

               (b) if there does not exist throughout such period a large blood
collection market for such Base Set, an amount equal to:

                      x
               y  -  --- where
                      z

               (x) equals the average Net Sales price for such Integrated
               Inactivation Set in such quarter;

               (y) equals the Base Revenue for such Base Set during the most
               recent three full month period in which there continuously
               existed a large clinical market for such Base Set, and

               (z) equals the average Net Sales price for such Integrated
               Inactivation Set during such three full month period (or shorter
               period since first sale of such Integrated Inactivation Set).

Baxter shall provide to Cerus information supporting such average net sales
price within sixty (60) days after the last day of the first calendar quarter in
which the first sale of each Integrated Inactivation Set occurs and sixty (60)
days after the last day of each calendar quarter thereafter. For the purposes of
this definition, a "large blood collection market" shall be deemed to exist for
any Base Set in any three-month period if Baxter has sales of such Base Set into
the blood collection (for transfusion) market of at least twenty-five percent
(25%) of the number of units of such Base Set that were sold in the three-month
period immediately preceding the first sale of the comparable Integrated
Inactivation Set. Baxter shall provide to Cerus within sixty (60) days after the
last day of each calendar quarter information for each such Base Set evidencing
whether or not there exists a large clinical market.

        BASE SET has the meaning set forth in the definition of Base Revenue.

        BAXTER means BHC and its affiliates, including, but not limited to,
divisions and subsidiaries, and also including its parent company, Baxter
International Inc. and its affiliates, including, but not limited to, divisions
and subsidiaries. A company shall be considered an affiliate of BHC if it is at
least forty percent (40%) owned or controlled by BHC or Baxter International
Inc.


                                       2.


<PAGE>   9
        BAXTER COMPOUNDS means any and all New Technology Compounds developed
by, licensed to, acquired by or otherwise commercially accessible to Baxter
prior to the Effective Date or in the course of the Cooperative Development
Work.

        BAXTER DESIGNATED CONSULTANTS means those persons who act on a regular
basis as consultants of Baxter, as adjuncts to Baxter management or staff, or as
members of the scientific advisory board or other boards or committees, as
distinguished from consultants or contractors who are engaged to perform
specific tasks in connection with the Cooperative Development Work.

        BAXTER INVENTION means an Invention that is solely owned by Baxter, or
which Baxter has the right to control the use of, relating to the Field and any
System, including methods for manufacture or use of Baxter Compounds and Systems
or portions thereof.

        BAXTER KNOW-HOW means Know-How proprietary to Baxter that is solely
owned by Baxter, or which Baxter has the right to control the use of, relating
to the Field and any System, including methods for manufacture or use of Baxter
Compounds and Systems or portions thereof. The term Baxter Know-How includes,
and is limited to, any of the foregoing in existence as of the Effective Date or
created or acquired during the term of the Cooperative Development Work.

        BAXTER NONCASH CONTRIBUTION shall be deemed to be [...***...] for the
Red Cell Project, [...***...] for the S59 FFP Project and such amount as the
parties may agree for any other Project, provided that if the parties do not so
agree, the Baxter Noncash Contribution for such Project shall be one-half of the
Initial Budget for the total Project, the amount of the Baxter Noncash
Contribution in each case being subject to adjustment as provided herein.

        BAXTER PATENTS means all United States and foreign patent applications
and patents that relate to the Approved Project Field and have claims reading on
Baxter Compounds or compositions or formulations thereof, or otherwise reading
on a System or portion thereof, or methods for manufacture or use of such System
or Baxter Compound, owned by Baxter or licensed to Baxter with the right to
sublicense, including any continuations, divisions, reissues, re-examinations
and all foreign counterparts thereof. The term Baxter Patents includes, and is
limited to, any of the foregoing in existence as of the Effective Date or
claiming an invention conceived or discovery made, or which are acquired, during
the term of the Cooperative Development Work.

        BAXTER PROJECT INVENTION means an Invention conceived by employees
and/or agents of Baxter (including Baxter Designated Consultants, but excluding
Inventions made solely by Contractors) alone or with third parties (excluding
Cerus) during the term of this Agreement pursuant to the Cooperative Development
Work. Without limiting the foregoing, Baxter Project Invention also includes any
such Invention conceived by employees or agents of a Contractor jointly with
employees or agents of Baxter (but not of Cerus).

        BULK FORM means Cerus Compounds which are not packaged in final form.

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                       3.


<PAGE>   10
        CERUS means Cerus Corporation, a company organized under the laws of
California and its affiliates, including, but not limited to, divisions and
subsidiaries. A company shall be considered an affiliate of Cerus if it is at
least forty percent (40%) owned or controlled by Cerus.

        CERUS COMPOUND(S) means any and all psoralen compounds, ALE compounds
and New Technology Compounds developed by, licensed to, acquired by or otherwise
commercially accessible to Cerus prior to the Effective Date or in the course of
the Cooperative Development Work.

        CERUS DESIGNATED CONSULTANTS means those persons who act on a regular
basis as consultants of Cerus, as adjuncts to Cerus management or staff, or as
members of the scientific advisory board or other boards or committees, as
distinguished from consultants or contractors who are engaged to perform
specific tasks in connection with the Cooperative Development Work.

        CERUS INVENTION means an Invention that is solely owned by Cerus, or
which Cerus has the right to control the use of, relating to the Field and any
System, including methods for manufacture or use of Cerus Compounds and Systems
or portions thereof.

        CERUS KNOW-HOW means Know-How proprietary to Cerus that is solely owned
by Cerus, or which Cerus has the right to control the use of, relating to the
Field and any System, including methods for manufacture or use of Cerus
Compounds and Systems or portions thereof. The term Cerus Know-How includes, and
is limited to, any of the foregoing in existence as of the Effective Date or
created or acquired during the term of the Cooperative Development Work.

        CERUS NONCASH CONTRIBUTION shall be deemed to be [...***...] for the Red
Cell Project, [...***...] for the S59 FFP Project and such amount as the parties
may agree for any other Project, provided that if the parties do not so agree,
the Cerus Noncash Contribution for such Project shall be one-half of the Initial
Budget for the total Project, the amount of the Cerus Noncash Contribution in
each case being subject to adjustment as provided herein.

        CERUS PATENTS means all United States and foreign patent applications
and patents that relate to the Approved Project Field and have claims reading on
Cerus Compounds or compositions or formulations thereof, or otherwise reading on
a System or portion thereof, or methods for manufacture or use of such System or
Cerus Compound, owned by Cerus or licensed to Cerus with the right to
sublicense, including any continuations, divisions, reissues, re-examinations
and all foreign counterparts thereof. The term Cerus Patents includes, and is
limited to, any of the foregoing in existence as of the Effective Date, or
claiming an invention conceived or discovery made, or which are acquired, during
the term of the Cooperative Development Work.

        CERUS PROJECT INVENTION means an Invention conceived by employees and/or
agents of Cerus (including Cerus Designated Consultants, but excluding
Inventions made solely by Contractors) alone or with third parties (excluding
Baxter) during the term of this Agreement pursuant to the Cooperative
Development Work. Without limiting the foregoing, Cerus Project Invention also
includes any such Invention conceived by employees or agents of a Contractor
jointly with employees or agents of Cerus (but not of Baxter).

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                       4.


<PAGE>   11
        COOPERATIVE DEVELOPMENT WORK means the Cooperative Development Work
defined in Section 3.1 of this Agreement.

        CONTRACTOR means a third party, other than a Baxter Designated
Consultant or Cerus Designated Consultant, performing a portion of the
Cooperative Development Work or investigation of New Technologies under a
contract with Baxter, Cerus, or Baxter and Cerus jointly.

        CONTRACTOR INVENTION means an Invention conceived by employees and/or
agents of a Contractor in the course of performing a portion of the Cooperative
Development Work or investigation of New Technologies under a contract with
Baxter, Cerus, or Baxter and Cerus jointly. For the purposes hereof, any such
Invention that is conceived by employees or agents of the Contractor jointly
with employees or agents of Baxter (but not of Cerus) shall be considered to be
a Baxter Project Invention, and not a Contractor Invention. Any such Invention
that is conceived by employees or agents of the Contractor jointly with
employees or agents of Cerus (but not of Baxter) shall be considered to be a
Cerus Project Invention, and not a Contractor Invention.

        COST OF GOODS means, for either party, such party's [...***...] such
items, in accordance with GAAP and in accordance with Baxter's normal accounting
policies, all consistently applied. Cost of Goods shall not include
[...***...]which are not directly related to [...***...]and shall not include
[...***...]or expenses falling under the category designated by Baxter "other
costs of sales" or similar category, however designated, unless otherwise agreed
by the Management Board. Capital expenditures for facilities and/or equipment
and capitalized manufacturing start-up costs will be amortized and included in
Cost of Goods. In the event any item is acquired by a party from an affiliate of
such party, [...***...] shall be deemed to mean such affiliate's [...***...].
For the purposes of this definition, an "affiliate" of a company shall mean an
entity controlling, controlled by, or under common control with such company.
"Control" for the purposes of this definition shall mean fifty percent (50%)
ownership.

        COST OF GOODS/BASE REVENUE for Cerus means Cerus' Cost of Goods. For
Baxter COST OF GOODS/BASE REVENUE means:

               (a) in the case in which the Inactivation Package is sold as a
stand-alone item, Baxter's Cost of Goods, or

               (b) in the case in which the Inactivation Package is sold as a
part of an Integrated Inactivation Set in any calendar year, the [...***...] (i)
[...***...], or (ii) [...***...]. An example of calculation of Cost of
Goods/Base Revenue is set forth on Schedule H to this Agreement.

        DESIGNATED CONSULTANTS means Baxter Designated Consultants and Cerus
Designated Consultants.

        DISTRIBUTOR PORTION means, for any Inactivation Package or Integrated
Inactivation Set sold through a distributor, the amount by which Net Sales price
therefrom exceeds the revenues from the sale of such items to the Distributor.

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                                       5.


<PAGE>   12
        EUROPE means any of the countries within the definition of Europe, as
such term is defined in the Platelet Agreement.

        EXCLUDED PRODUCT has the meaning provided in Section 8.7 of this
Agreement.

        FDA means the United States Food and Drug Administration.

        FFP means human fresh frozen plasma.

        THE FIELD means, subject to the exceptions set forth in Section 8.5
hereof, [...***...]; in each case that are obtained from [...***...]. The Field
includes[...***...]. The Field does not include, however, any [...***...] to
make, enable, or improve the [...***...]. The preceding sentence is not
intended, however, to exclude (a) the use of such [...***...] falling within
clause (i) or (ii) above, or (b) the [...***...] falling within clause (i) or
(ii) above, in which the [...***...]. Cerus reserves all rights to [...***...]
using Cerus Compounds in which the intended use of the [...***...]. The Field
also excludes [...***...].

        FINAL PROJECT TOTAL BUDGET means the total cost and expense of
developing a System up to and including obtaining Regulatory Approval to market
the System in the countries in which the Management Board (or Cerus in the case
of the S59 FFP Project) determines that Regulatory Approval should be sought and
any other items of cost or expense that this Agreement expressly requires to be
included in Final Project Total Budget. In the event either party, to the extent
permitted under Section 3.6(b) of this Agreement, elects not to share in the
costs of Regulatory Approval of a Project in a particular country, the Final
Project Total Budget shall be adjusted solely as to such country by adding to
the overall Final Project Total Budget the amount of the incremental
expenditures incurred by the party bearing the costs of Regulatory Approval in
such country and such party's cash contribution to the Project solely as to such
country will be increased by adding the amount of such expenditures to such
party's overall cash contribution to the Project. The preceding sentence shall
not apply, however, with respect to the S59 FFP Project.

        GAAP means generally accepted accounting principles, consistently
applied.

        INACTIVATION PACKAGE means the package containing one or more Cerus
Compounds, Baxter Compounds and/or New Technology Compounds, as well as the
delivery system (consisting of all disposables and compound removal device, if
any, associated with a System).

        INITIAL BUDGET means the budget first approved by the Management Board
for developing a particular Project to Regulatory Approval, which for Red Cell
Project means Regulatory Approval in the United States and Europe, and for the
S59 FFP Project means Regulatory Approval in the United States.

        INSTRUMENT means an instrument or instruments to be developed or adapted
under the Cooperative Development Work and may include associated data tracking
systems.

        INTEGRATED INACTIVATION SET means an integrated set containing an
Inactivation Package and other collection or storage items.

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                                       6.


<PAGE>   13
        INVENTION means a patentable invention or discovery.

        JOINT INVENTIONS means an Invention relating to the performance of this
Agreement, conceived jointly by one or more employees or agents (including
Baxter Designated Consultants) of Baxter and one or more employees or agents
(including Cerus Designated Consultants) of Cerus.

        JOINT JAPAN FFP DISTRIBUTION PARTNER has the meaning set forth in
Section 6.1 hereof.

        JOINT PATENTS means all United States and foreign patent applications
and patents claiming an invention owned by, or licensed to both Cerus and
Baxter, including any continuations, divisions, reissues, re-examinations and
all foreign counterparts thereof. Without limiting the foregoing, Joint Patents
includes the patents and patent applications claiming a Contractor Invention of
which either Baxter or Cerus gains ownership or license, as set forth in Section
8.3(d).

        KNOW-HOW means inventions, or data, processes, compositions, techniques
and other technical information that are not patentable or for which patent
protection is not sought.

        MANAGEMENT BOARD means the Management Board created pursuant to Section
3.2 hereof.

        MARKET LAUNCH of a System in a given country is deemed to be the earlier
of (1) the date of first commercial sale following Regulatory Approval for sale
of the System in that particular country or (2) the ninetieth (90th) day
following Regulatory Approval for commercial sale of that System in that
country.

        MARKETING AND ADMINISTRATIVE EXPENSES for a party in any calendar year
is that percentage of such party's Net Sales (minus Base Revenue in the case of
sales of Integrated Inactivation Sets) for costs incurred in marketing, selling
and administering the Systems, established as follows:


<TABLE>
<CAPTION>
               AGGREGATE NET SALES                             PERCENTAGE APPLIED
                 OF SUCH PARTY                                 TO ALL NET SALES IN
               IN SUCH CALENDAR YEAR                           SUCH CALENDAR YEAR
               ---------------------                           ------------------
<S>                                                            <C>
               Under [...***...]                                [...***...]
               [...***...] up to [...***...]                    [...***...]
               [...***...] up to [...***...]                    [...***...]
               Over [...***...]                                 [...***...]
</TABLE>

(All dollar amounts in this definition are expressed in U.S. dollars, converted
from foreign currencies in accordance with Section 7.1 hereof). For the purpose
of determining Premium for the first three quarterly Revenue Sharing Payments
for any calendar year, the percentage used as set forth above to compute a
party's Marketing and Administrative Expenses will be based on the party's bona
fide forecast of Net Sales in such calendar year used for its internal
management purposes (which information will be provided to the Management
Board). If actual aggregate 

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                                       7.


<PAGE>   14
annual Net Sales vary from such projections to an extent that would cause a
change in the applicable percentage rate for such calendar year, such first
three quarterly Revenue Sharing Payments will be appropriately adjusted
retroactively in the final Revenue Sharing Payment for such calendar year (i.e.,
the First Revenue Sharing Payment date in the following calendar year) and
additional payments will be made to the receiving party, or amounts reimbursed
from the receiving party, to yield the actual Revenue Sharing Payment to which
the receiving party is entitled based on the level of actual Net Sales in such
calendar year.

        NET SALES means

               (a) in the case of the Inactivation Package sold as a stand-alone
item or as part of an Integrated Inactivation Set, the amount invoiced by Baxter
for sales, leases, or licenses of the stand-alone Inactivation Package or
Integrated Inactivation Set, less credits or allowances, if any, for rejections
or returns, customary trade discounts actually given, less customs and duties
paid; less separately invoiced and actually incurred taxes and other
governmental charges that are imposed directly on or measured by the sale,
transfer, transportation, delivery or use of an Inactivation Package; and less
freight paid by Baxter on shipment from Baxter to end users.

               (b) In the event any Inactivation Package or Integrated
Inactivation Set is bundled (whether or not invoiced separately) and sold at a
discount with other products for whatever reason, including a special
promotional offer, or in the event of any transaction other than a bona fide
arms length transaction exclusively for money, or upon any use of such
Inactivation Package or Integrated Inactivation Set for purposes which do not
result in customary sales revenue, such sale or other disposal or use shall be
(unless the parties agree otherwise) deemed to constitute a sale at the then
current average selling price for the Inactivation Package or Integrated
Inactivation Set, as the case may be.

               (c) In the case of sales by Baxter to a distributor, the Net
Sales shall be computed on the distributor's invoice price to the ultimate
purchaser or user. In the event that Baxter is not able to determine the price
charged by a distributor to the ultimate purchaser or user, such price shall be
the recommended price which Baxter, at the direction of the Management Board,
recommends the distributor to charge to its end customers (which may vary from
territory to territory).

               (d) In the event Baxter or Cerus, in accordance with policies
established by the Management Board, supplies Instruments to end users without
charge in return for an increased price of Inactivation Packages to such end
users, Baxter or Cerus, as the case may be, may deduct from Net Sales received
from such end users the depreciation of the cost of such Instruments. In the
event such Instruments are also used in connection with products supplied by
Baxter or Cerus other than the Inactivation Packages or Integrated Inactivation
Sets developed under this Agreement, then the amount of such depreciation to be
deducted in any quarter from Net Sales shall be limited to that portion of the
depreciation reasonably allocable to the use of the Instruments in connection
with Inactivation Packages and Integrated Inactivation Sets, in accordance with
policies established by the Management Board. In the case of such Instruments


                                       8.


<PAGE>   15
that are supplied into facilities using both platelet pathogen inactivation
systems and S59 FFP Systems, Baxter or Cerus as the case may be, may
[...***...].

               (e) In the event that the ultimate purchaser or end user is
assessed a charge by Baxter on a per-inactivation or other usage basis, the
amount of such charge shall be included in Net Sales.

               (f) If the term "Net Sales" is used in reference to Systems sold
by Cerus, the word "Baxter" in this definition shall be deemed to mean "Cerus,"
except with respect to paragraph (c) above for the sale by Cerus of S59 FFP
Systems. Paragraph (c) above also does not apply to sale by a Joint Japan FFP
Distribution Partner of S59 FFP Systems. In the case of sales of S59 FFP Systems
by Cerus through a distributor or by a Joint Japan FFP Distribution Partner, Net
Sales will be the [...***...], subject to adjustment as provided in paragraphs
(a) and (b) of this definition, or if the distributor or Joint Japan FFP
Distribution Partner is [...***...].

        NEW TECHNOLOGY means New Technology as defined in Section 3.8 hereof.

        NEW TECHNOLOGY COMPOUND(S) means any compound employed in a New
Technology to which rights are acquired pursuant to Section 3.8 hereof. 

        NONCASH CONTRIBUTION means the Baxter Noncash Contribution and/or the
Cerus Noncash Contribution, as the context requires.

        PATENT COMMITTEE means a committee established by the Management Board
to review and report to the Management Board on patent matters pertaining to
this Agreement, and which will be comprised of an equal number of Baxter members
and Cerus members.

        PATENT FEE PAYMENT means an upfront license fee, milestone payment or
other financial consideration to a third party, other than a royalty on
percentage-of-sales or per-unit basis, for manufacture, use or sale of a System
or portion thereof.

        PATENT ROYALTY PAYMENT means a patent royalty payment on a
percentage-of-sales or per-unit basis made to a third party for manufacture, use
or sale of a System or portion thereof. Under this Agreement, the term Patent
Royalty Payment includes minimum royalty payments, but does not include any
Patent Fee Payment.

        PLATELET AGREEMENT means that certain Development, Manufacturing and
Marketing Agreement between the parties dated as of December 10, 1993, as the
same may be amended from time to time.

        PLATELET PROJECT means the "Cooperative Development Work" provided for,
and as defined in, the Platelet Agreement.

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                                       9.


<PAGE>   16
        PREMIUM means the Net Sales price of an Inactivation Package or
Integrated Inactivation Set minus each Party's Cost of Goods/Base Revenue in the
Inactivation Package or Integrated Inactivation Set, minus Marketing and
Administrative Expenses and [...***...] on [...***...] on [...***...], provided,
however, that on sales through a Joint Japan FFP DistriBuTION Partner,
[...***...] in computing Premium.

        PROJECT means the Cooperative Development Work performed by the Parties
to develop, obtain Regulatory Approval of, and market a System for a specific
application within the Field.

        PROJECT PATENT(S) means any Baxter Patent, Cerus Patent or Joint Patent
that the Management Board has designated a Project Patent pursuant to Section
9.5 hereof.

        RED CELL means, when used in reference to a Project, the Cooperative
Development Work to develop a System for inactivation of pathogens in human red
blood cells and, when used in reference to a System, Inactivation Package,
Instrument, or other item, the System, Inactivation Package, Instrument or other
item, developed or under development pursuant to such Cooperative Development
Work.

        REGULATORY APPROVAL means (1) in the United States, approval from the
FDA for marketing and promotion of the System, or (2) outside of the United
States, an analogous order by a non-U.S. governmental agency which requires
regulatory approval prior to marketing and promotion of a System in such
non-U.S. country.

        REVENUE SHARING FORMULA means the relative percentage interest of Baxter
and Cerus as set forth in Section 7 hereof.

        REVENUE SHARING PAYMENTS has the meaning set forth in Section 7.1
hereof.

        S59 FFP means when used in reference to a Project, the Cooperative
Development Work to develop a System for inactivation of pathogens in human
fresh frozen plasma through use of the psoralen compound designated by Cerus as
S59 and, when used in reference to a System, Inactivation Package, Instrument,
or other item, the System, Inactivation Package, Instrument or other item,
developed or under development pursuant to such Cooperative Development Work.

        SPECIAL PREFERRED STOCK means that Preferred Stock issued by Cerus to
Baxter pursuant to that certain Series A Preferred Stock Purchase Agreement
dated as of the First Amendment Effective Date and that Preferred Stock, if any,
issued by Cerus to Baxter pursuant to Section 19 of this Agreement.

        STAND-ALONE OR STAND-ALONE, in reference to an Inactivation Package,
means an Inactivation Package that is not integrated with other collection or
storage items, and which may take the form, for example, of a bag and tube set
that may be sterile docked, a syringe or ampule.

        SYSTEM(S) means a pathogen inactivation system developed pursuant to the
Cooperative Development Work for use in the Field, incorporating one or more
Cerus Compounds, Baxter Compounds and/or New Technology Compounds in an
Inactivation Package, and the following, 

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                                      10.


<PAGE>   17
if any, designed for or adapted for use with such compound(s): an Instrument,
and associated computer software, and any other disposables, delivery systems or
other components.

        SYSTEM IMPROVEMENTS means those improvements of commercial Systems
approved by the Management Board. The Management Board shall approve and manage
a budget for all System Improvements (System Improvement Costs).

        SYSTEM SPECIFICATIONS means the performance, cost, quality and
reliability requirements as the Management Board agrees must be met by a System
in order for the System to be acceptable for marketing and distribution
hereunder.

3.      COOPERATIVE DEVELOPMENT WORK.

        3.1 PERIOD; OBJECTIVE. From the Effective Date, Baxter and Cerus shall
work together to develop and obtain Regulatory Approval for (the "Cooperative
Development Work"), and thereafter market, Systems in the Field. As of the First
Amendment Effective Date, the approved Projects are the Red Cell Project and the
S59 FFP Project, each directed towards the development of Systems to be sold to
customers. The parties agree also to consider and negotiate in good faith the
terms (including, without limitation, funding, license and appropriate revenue
sharing) for the potential central processing and sale of human red blood cells
that have been subjected to pathogen inactivation using processes and compounds
in the Approved Project Field. The Management Board may from time-to-time
approve specific other Projects within the Field.

        3.2 MANAGEMENT BOARD.

               (a) CONSTITUTION. Cerus and Baxter will appoint a five (5) person
Management Board consisting of two (2) senior executives designated by each
company and one (1) independent member chosen by mutual agreement of the
Parties. The purpose of the Management Board will be to facilitate the overall
relationship of the parties under this Agreement and to manage the research,
development and marketing of Projects within the Field. System Specifications
recommended by the Parties shall not be deemed finalized until they are approved
by the Management Board. The Management Board shall meet from time to time as
appropriate, but no less frequently than four (4) times during each calendar
year, alternating between the offices of the parties, unless the parties shall
agree otherwise. The Management Board shall review and approve budgets, resource
allocations, Projects undertaken within the Field, sales and marketing plans and
expenditures.

               (b) PROJECT COMMITTEES. The Management Board shall create a
project committee for each Project approved by the Management Board under this
Agreement. The purpose of a project committee will be to oversee the Project for
which such committee is responsible and to manage the day-to-day operational
aspects of the Cooperative Development Work relating to that Project. A project
committee shall have only that authority specifically granted to it by the
Management Board, which authority shall include, without limitation, the
following responsibilities with respect to such Project:

                      (i) prioritization of specific aspects of the Cooperative
Development Work;


                                      11.


<PAGE>   18
                      (ii) allocation of financial, administrative, human and
other resources;

                      (iii) preparation of a proposed budget for consideration
by the Management Board at such times as requested by the Management Board (but
not less than annually); and

                      (iv) conducting bi-monthly reviews of the Cooperative
Development Work.

Notwithstanding the foregoing, a project committee shall never have the
authority to disburse funds or reimburse expenses without the express prior
approval of the Management Board.

               (c) PATENT COMMITTEE. The Management Board shall create a Patent
Committee to manage all patent matters relating to this Agreement. The Patent
Committee shall have only that authority specifically granted to it by the
Management Board, which authority shall include, without limitation, the
following responsibilities:

                      (i) prior review and approval of all patent applications
and prosecutions regardless of whether the application or prosecution relates to
a Baxter Patent, Cerus Patent or Joint Patent;

                      (ii) consulting with the Management Board with respect to
the periodic reviews of Project Patents pursuant to Section 9.5 of this
Agreement; and

                      (iii) conducting semi-annual reconciliations of the
expenses of preparing, filing, prosecuting and maintaining Project Patents and
Joint Patents pursuant to Section 9.6 of this Agreement.

               (d) VOTING. All decisions of the Management Board [...***...]
shall be made by majority vote or written consent, with Baxter and Cerus each
having one vote regardless of the number of representatives attending any
meeting. On all decisions as to [...***...]. The independent member shall vote
on all deadlocks of the Management Board [...***...]; provided however, the
independent member shall not vote, [...***...], on matters pertaining to any
dispute concerning the parties' legal obligations to each other for disbursement
of funds or the reimbursement of expenses under any circumstances. In the event
of a deadlock that may be broken by the independent member, either Baxter or
Cerus may notify the other party and the independent member in writing of the
existence of such deadlock and provide to each the specific resolution that such
party proposes to be adopted by the Management Board. Each party will have
thirty (30) days from such notice to present its position to the independent
member, which shall include at least one meeting at which both parties and the
independent member are present. Either Baxter, Cerus or the independent member
may, by notice to the others, shorten such time period if such party believes
that urgent action is required on the matter at issue. The independent member
shall render his or her vote on such resolution as promptly as possible, and in
no event later than twenty (20) days after such time period. In the event of a
deadlock between the parties on a decision whether to discontinue Cooperative
Development Work on a Project or to reduce funding for a Project, the
independent member shall not break the deadlock and the Project will continue
without reduction of funding level, subject to the right of either 

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CONFIDENTIAL TREATMENT REQUESTED

                                      12.


<PAGE>   19
party to cease participation in such Project, as provided in Section 12 hereof.
Any compensation of the independent member shall be by mutual agreement of the
Parties and shall be subject to cost sharing. The independent member shall vote
on all matters in a manner that in the good faith judgment of the independent
member is in Baxter and Cerus' best interests as risk and revenue sharers under
this Agreement (i.e. in the same manner that a corporate director would vote in
the best interests of the shareholders of a corporation). Baxter and Cerus will
indemnify and hold harmless the independent member against any claim arising
from a decision made by the independent member, so long as such decision was
made in good faith. The independent member may be removed and/or replaced by
mutual written consent of Baxter and Cerus.

               (e) DISPUTES.

                      (i) In the event that there is a deadlock on any issue
within the authority of the Management Board as to which the independent member
would be authorized to break the deadlock, and at that time there is not an
independent member (or for any reason the independent member does not break such
deadlock), either party may apply to the AAA to appoint an individual, in
accordance with the rules of the AAA who will act in the capacity of independent
member solely for the purpose of breaking such deadlock and resolving such
issue. Prior to making such application, a party will provide to the other party
ten (10) days' advance written notice of its intent to do so. During such ten
(10) day period, the parties will use their good faith best efforts to resolve
such issue in a meeting between the chief executive officer of Cerus and the
highest ranking officer of Baxter, Fenwal Division or comparable successor
division or entity, or failing such resolution, to agree upon appointment of an
independent member. Each party will in all cases cooperate in providing the
independent member such information as the independent member may request in
considering any matter.

                      (ii) With respect to any issue that is not within the
authority of the Management Board to resolve or with respect to which the
independent member is not authorized to break the deadlock, other than an issue
concerning S59 FFP on which the Cerus representatives are entitled to cast the
deciding vote, then the matter shall be finally settled by arbitration, to be
held in Chicago, Illinois, in accordance with the Commercial Arbitration Rules
of the American Arbitration Association ("AAA"). Any such dispute or controversy
shall be arbitrated before three arbitrators selected in accordance with the
rules of the AAA. The arbitrators' decision shall be final and binding upon the
parties. The parties shall be entitled to full discovery in any such
arbitration. Each party shall bear one half of the cost of such arbitration,
unless the arbitrators otherwise allocate such costs. During the period of any
arbitration, each party shall pay to the other party any amounts that are or
become due and owing to such other party, other than amounts being contested in
good faith in the arbitration.

        3.3 REVIEW OF BUDGET, BENCHMARKS; APPROVED PROJECTS. The benchmarks,
budget and timetable for all Projects, other than the S59 FFP Project, will be
reviewable by the Management Board from time-to-time during the Cooperative
Development Work with the intent that the parties move expeditiously and
effectively toward commercialization of any System. Cerus will inform Baxter
from time-to-time of the benchmarks, budget and timetable for the S59 FFP
Project. Baxter commits that for calendar years [...***...], Baxter will expend
on the Platelet Project and the Red Cell Project an aggregate amount of
[...***...] per calendar 

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                                      13.


<PAGE>   20
year, all of which will be current expenditures for project tasks, except for
those limited amounts to be applied to the accounting category of amortization
in each calendar year, as set forth on the amortization schedule attached as
Schedule I to this Agreement. Unless the parties mutually agree otherwise, such
expenditures will be applied first to [...***...], and next to [...***...],
allocated between such Projects in such amounts as the Management Boards under
the Platelet Agreement and this Agreement shall determine. Such committed amount
will be increased in any calendar year only if, and to the extent, the combined
project budgets approved by the Management Boards under the Platelet Agreement
and for the Red Cell Project exceed such committed amount for such calendar
year. If, for any reason, such full amount cannot usefully be spent in pursuit
of the [...***...], any amounts not so spent ("Excess Funds") shall be applied
to fund New Technologies selected by the Management Board pursuant to Section
3.8 hereof. If the Management Board determines that any such Excess Funds cannot
usefully be spent on New Technologies selected by the Management Board pursuant
to Section 3.8 hereof, such Excess Funds shall be released from the funding
commitment of this paragraph.

               (a) THE RED CELL PROJECT. The Initial Budget for one Project
approved, as of the Effective Date, by the Management Board is the Red Cell
Project, attached hereto as Schedule A-1. The approved budget for 1998 for the
Red Cell Project, as amended, is attached hereto as Schedule A-2. The parties
agree to establish a reasonable budget for subsequent periods for the Red Cell
Project, unless the Management Board determines to discontinue such Project.
Each party shall perform the respective tasks set forth on Schedules A-1 and
A-2, except as the Management Board shall otherwise determine.

                      (i) All funding of the Red Cell Project was provided by
Cerus, until [...***...]. Baxter commenced participation as of January 1, 1997,
and Baxter shall continue to participate, in the Red Cell Project in accordance
with this Agreement, including without limitation, the obligation to share fifty
percent (50%) of the costs and expenses of the Cooperative Development Work
incurred on or after January 1, 1997, and to market and sell the Systems for Red
Cells developed under this Agreement; provided that Baxter's obligation to bear
fifty percent (50%) of the costs and expenses for 1998 is subject to Section
3.3(a)(iii) hereof. Subsequent to the date of achievement of the Platelet
Milestone, Baxter paid to Cerus, subject to final reconciliation, fifty percent
(50%) of the amount expended by Cerus under the Project budget from January 1,
1997 through December 31, 1997. Baxter shall pay to Cerus on July 1, 1998, and
on each January 1 and July 1 thereafter, the amount by which Cerus budgeted
expenditures under the then current Project budget for the then current calendar
year (including amounts budgeted to be expended by Cerus on outside expenses)
exceeds fifty percent (50%) of the budgeted expenditures for such period;
provided that for 1998 such payment obligations will be subject to Section
3.3(a)(iii) hereof. Such excess budgeted expenditures to be paid to Cerus for
any calendar year will be divided between the January 1 payment and the July 1
payment in amounts that approximate the expected excess expenditure levels over
the course of such year, as the parties may agree. Failing such agreement, 50%
of such excess budgeted amount shall be paid on January 1, and 50% shall be paid
on July 1.

                      (ii) The parties acknowledge that the Platelet Milestone
was achieved on September 30, 1997.

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                                      14.


<PAGE>   21
                      (iii) Notwithstanding the foregoing provisions of this
Section 3.3.(a), to the extent the approved budget for 1998 for the Red Cell
Project exceeds Eight Million Three Hundred Thousand Dollars ($8,300,000), Cerus
will fund all expenses for the Red Cell Project in 1998 in excess of such
amount, up to the amount of the approved budget ("Cerus 1998 Excess
Expenditures"). To compensate for the Cerus 1998 Excess Expenditures, Baxter
will fully fund the first expenditures under the approved budget for the Red
Cell Project for 1999 in an amount equal to the Cerus 1998 Excess Expenditures
(such amounts being included in Baxter's funding commitment pursuant to Section
3.3 hereof), after which the parties shall equally share the expenses of the Red
Cell Project. If there is for any reason not an approved budget for the Red Cell
Project for 1999, Baxter will fully fund the first expenditures for 1999 under
the approved budget for such other Cerus-Baxter program or programs as Cerus
shall designate in an amount equal to the Cerus 1998 Excess Expenditures. If by
July 1, 1999, however, there is not an approved budget for such other
Cerus-Baxter program or programs that is at least equal to such Excess
Expenditures, Baxter will promptly pay to Cerus one-half of the amount by which
the Excess Expenditures exceed the amount of expenditures to be funded by Baxter
under the preceding sentence.

               (b) THE S59 FFP PROJECT. The Initial Budget for one Project
approved, as of the Effective Date, by the Management Board is the S59 FFP
Project, attached hereto as Schedule B.

                      (i) All funding of the S59 FFP Project was provided by
Cerus, until achievement of the Platelet Milestone. Baxter commenced
participation as of January 1, 1997, and Baxter shall continue to participate in
the S59 FFP Project in accordance with this Agreement, including without
limitation, the obligation to share fifty percent (50%) of the costs and
expenses of the Cooperative Development Work incurred on or after January 1,
1997 and through December 31, 1997, and to market and sell the S59 FFP Systems
developed under this Agreement. Following December 31, 1997, Baxter's obligation
to share costs shall be fixed at [...***...] of which will be paid on January
10, 1999 and [...***...] of which will be paid on January 10, 2000. Except as
set forth in the preceding sentence, Cerus will bear all expenses of the
Cooperative Development Work for the S59 FFP Project after December 31, 1997.
Subsequent to the date of achievement of the Platelet Milestone, Baxter paid to
Cerus (subject to final reconciliation) fifty percent (50%) of the amount
expended by Cerus under the Project budget from January 1, 1997 through December
31, 1997.

                      (ii) The parties acknowledge that the Platelet Milestone
was achieved on September 30, 1997.

                      (iii) Baxter will supply such support of its technical
personnel as Cerus shall reasonably request from time to time for development of
the S59 FFP System. Cerus shall reimburse Baxter the cost of providing such
support, accounted for on average cost per full time equivalent basis consistent
with Section 3.5(a) hereof; provided that Cerus will be entitled to a credit
against any such costs for expenses incurred by Cerus in support of the
methylene blue project, accounted for in the same manner. Such expenses will be
paid at the time of semi-annual reconciliation pursuant to Section 3.7(b).

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                                      15.


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               (c) OTHER PROJECTS. The budget for any other project the parties
agree to cooperate on (other than the Red Cell Project and the S59 FFP Project)
shall be approved by the Management Board. Upon the approval of the Initial
Budget for each such project and upon each anniversary of the date thereof,
Baxter shall pay to Cerus, or Cerus shall pay to Baxter, the amount by which
such party's budgeted expenditures under the then current budget for the
succeeding twelve-month period (including amounts budgeted to be expended by
such party on outside expenses) exceeds 50% of the total then budgeted
expenditures for such period.

        3.4 EXCHANGE OF INFORMATION. During the term of the Cooperative
Development Work, the parties shall exchange all material information developed
pursuant to the Cooperative Development Work including the exchange of Baxter
Know-How and information concerning Baxter Patents and Cerus Know-How and
information concerning Cerus Patents relating to the Field. The exchange shall
occur pursuant to Section 11. The Systems shall embody and use such Cerus
Patents and Cerus Know-How and Baxter Patents and Baxter Know-How as shall be
determined by the Management Board.

        3.5 COST SHARING. Except as otherwise provided in this Agreement,
commencing January 1, 1997, Baxter will fund fifty percent (50%) and Cerus will
fund fifty percent (50%) of the Cooperative Development Work with respect to
each Project; provided that Baxter's obligation to fund Cooperative Development
Work for the S59 FFP Project shall be limited as provided in Section 3.3(b)(i).
Funding shall include all costs and expenses incurred in connection with the
Cooperative Development Work. Cost and expenses shall include only those
expenditures made in accordance with Project budgets approved by the Management
Board related to research, development, clinical trials, Regulatory Approval and
other expenses that this Agreement expressly provides shall be subject to cost
sharing; provided however that Management Board approval shall not be required
for S59 FFP Project budgets, except with respect to System Improvements under
Section 5.8. In the event that the funding for the Cooperative Development Work
for any Project, other than the S59 FFP Project, is not shared equally
commencing January 1, 1997, then (except as otherwise provided in Section 12 or
Section 16 hereof) the Revenue Sharing Formula in Section 7.1 for such Project
shall be adjusted such that the percentage of Premium received by a party will
equal the percentage contributed by such party to the sum of (a) the cash
contributed to the Final Project Total Budget commencing January 1, 1997, plus
(b) Noncash Contribution to the Project. Capital expenditures for facilities
and/or equipment and capitalized manufacturing start-up costs will not be
included in costs and expenses shared.

               (a) Each party shall maintain detailed records which accurately
identify costs and expenses incurred and paid in connection with the Cooperative
Development Work for each specific Project. Except as to expenses incurred by
Cerus after June 30, 1998 on the S59 FFP Project, each party shall submit this
information to the Management Board on the on the last business day of February
for the period ending December 31, and on the last business day of August for
the period ending June 30 (or such alternative dates as the Management Board may
establish) along with an estimate of expenses to be incurred during the current
six months. Expenses internally generated because tasks are performed by a
party's own staff will be accounted for on a uniform average cost per full time
equivalent basis.


                                      16.


<PAGE>   23
               (b) All costs with respect to participation on the Management
Board during the Cooperative Development Work, including travel expenses for
meetings and participation on the Management Board, shall be subject to cost
sharing.

        3.6 TESTING AND REGULATORY EXPENSES.

               (a) TESTING EXPENSES. All expenses incurred in connection with
any testing whose primary function is marketing of the System, rather than
developing the System or obtaining Regulatory Approval of the System, shall be
borne solely by Baxter and shall not be considered expenses subject to cost
sharing, unless the Management Board determines that such expenses should be
considered part of the Cooperative Development Work.

               (b) REGULATORY EXPENSES. The Management Board shall determine the
countries in which Regulatory Approval will be sought and the timing of seeking
such Regulatory Approval. All expenses incurred to obtain Regulatory Approval
are expenses subject to cost sharing under Section 3.5 and shall be part of the
Final Project Total Budget, it being understood that Baxter's obligation to
share expenses for the S59 FFP Project shall be limited as provided in Section
3.3(b)(i); provided, however, that either party may, by notice given to the
other party within thirty (30) days after such Management Board decision with
respect to a particular country, elect to not share in the costs of Regulatory
Approval in not more than five (5) countries outside of North America and
Europe, which will result in an adjustment for each such country of Final
Project Total Budget (as further provided in the definition of "Final Project
Total Budget").

        3.7 BUDGET CONTINGENCIES.

               (a) EXCEEDING INITIAL BUDGET. If the Management Board establishes
a budget for a new Project, or determines that the budget for an approved
Project within the Field must be increased over the previously established
budget for the Project, then Baxter will fund fifty percent (50%) and Cerus will
fund fifty percent (50%) of the new Project budget or of any increase in the
previously approved budget, excluding any budget for the S59 FFP Project after
June 30, 1998, which shall be funded solely by Cerus. In the event of any new
Project budget or budget increase (excluding for the S59 FFP Project), however,
either party may, by written notice to the other party, elect to fund less than
its full share (50%) of such new Project budget or budget increase. In such an
event, the funding party may, by written notice to the non-funding party, elect
to assume responsibility for the funding of such unfunded amount, in which event
(except as otherwise provided in Section 12 and Section 16 hereof) the Revenue
Sharing Formula in Section 7.1 for such Project will be adjusted such that the
percentage of Premium to be received by a party will equal the percentage
contributed by such party to the sum of (i) the cash contributed to Final
Project Total Budget commencing January 1, 1997 (excluding 1996 carryovers as
described in Section 3.5), plus (ii) total Noncash Contribution to the Project.

               (b) RECONCILIATION OF EXPENDITURES. Unless otherwise agreed, the
Management Board shall reconcile actual cash outlays and expenses approved by
the Management Board with respect to a Project on a semi-annual basis such that
costs have been incurred in the proportion of fifty percent (50%) by Baxter and
fifty (50%) by Cerus (subject to adjustments pursuant to Section 3.3(a)(iii)
hereof and except as provided in Section 3.3(b)(i) hereof with respect S59 FFP),
or such other ratio as is established pursuant to Section 3.7(a). If 


                                      17.


<PAGE>   24
they are not in such proportion, Cerus will make a cash payment to Baxter, or
Baxter will make a cash payment to Cerus, in order to achieve such proportion.
The payment shall be made in cash within thirty (30) days following the
determination by the Management Board based upon the reports made pursuant to
Section 3.5(a) of this Agreement.

        3.8 NEW TECHNOLOGIES.

               (a) In the event either party learns of a possibility to acquire
ownership of, or obtain a license or option to, a technology (including without
limitation any method, Know-How, Invention or composition of matter)

                      (i) that might enable or improve a System being developed
under the Agreement, or

                      (ii) that might form the basis for a new System that might
be developed under this Agreement in the Field,

(a "New Technology") such party will notify the other party of such possibility,
and the Management Board will consider whether to pursue the acquisition of
rights to such New Technology. If the Management Board determines to pursue the
acquisition of rights to such New Technology in the Field, each party will have
the right to become a joint owner of any New Technology acquired, or joint
licensee of any New Technology so licensed, subject to such party sharing 50%
(unless the parties agree in writing to another percentage) of the cost of
acquiring ownership of, or obtaining a license to, such technology.
Notwithstanding the foregoing, if the Management Board determines to pursue a
New Technology that has use outside the Field, as well as within the Field, the
party who identified such opportunity shall, unless the parties agree otherwise,
have exclusive rights to practice such New Technology outside the Field, and the
other party will be required to share 50% (unless the parties agree in writing
to another percentage) of only that portion of the cost of acquiring ownership
of, or obtaining a license to, such New Technology that is allocable to its
value for use within the Field. Such allocable value shall be determined by
mutual agreement, or failing such agreement, by arbitration pursuant to Section
3.2(d)(i) hereof. Any New Technology to which rights are jointly acquired by the
parties may be exploited by either party within the Field solely under, and in
accordance with, the terms (including, without limitation, sharing of
development expenses and revenues) of this Agreement, unless the parties
otherwise expressly agree in writing to other terms.

               (b) If the Management Board determines not to pursue the
acquisition of rights in a New Technology, due to the negative vote of the
representatives of one party, the other party (if the representatives of such
party voted in favor of acquiring rights to the New Technology), at its sole
expense, may acquire ownership of, or obtain a license to, such New Technology
and may exploit such New Technology within or outside the Field free of any
obligations under this Agreement, other than the obligation to pay a reasonable
royalty on the practice of a Joint Invention, as provided in Section 8.6(b)
hereof. Notwithstanding the foregoing, the right of exploitation by one party
shall not be construed to grant any license to any patents or other proprietary
rights of the other party, and the only licenses hereunder that may be practiced
for such purpose are the licenses set forth in Section 8.6.

               (c) In addition to the provisions concerning New Technologies set
forth in Sections 3.8(a) and 3.8(b) above, in the event either party proposes to
pursue development or 


                                      18.


<PAGE>   25
marketing of any product within the Field, such party will present such proposal
to the Management Board, together with a reasonably detailed business plan and a
proposed budget for such project. If the Management Board determines to pursue
such project, such project shall become a Project under the Cooperative
Development Work pursuant to Section 3.3(d) of this Agreement. If the Management
Board determines not to pursue such project, due to the negative vote of the
representatives of one party, the other party (if the representatives of such
party voted in favor of the proposal) may pursue such project free of any
obligations under this Agreement. Notwithstanding the foregoing, the right to
pursue such project by one party shall not be construed to grant any license to
any patents or other proprietary rights of the other party, and the only
licenses hereunder that may be practiced for such purpose are the licenses set
forth in Section 8.6.

               (d) Without limiting the foregoing, or any other provisions of
this Agreement, each party agrees that in the Approved Project Field, except as
otherwise provided in Sections 3.8(b) and 3.8(c), it will make available
exclusively for the Cooperative Development Work and for embodiment in Systems
(without any consideration other than as provided in this Agreement) any
technology (including without limitation, any method, Know-How or composition of
matter) useful within the Approved Project Field owned or controlled by such
party as of the First Amendment Effective Date or of any time thereafter, and
each party will use reasonable efforts to inform the other party of any such
technology that may reasonably appear useful within the Field. This Section
3.8(d) is not intended to limit or restrict any use or commercialization of any
such technology outside the Approved Project Field.

               (e) Each party agrees not to unreasonably delay any vote on a
proposal pursuant to Section 3.8(a) or 3.8(c), nor to withhold or delay approval
of a reasonable budget to pursue any such proposal that is approved by the
Management Board, and each party will provide committed funding for expenditures
in accordance with such budget commencing, unless the parties otherwise agree,
not later than the calendar year following the year in which such proposal is
approved by the Management Board.

        3.9 COORDINATION AND FACILITATION OF COMMUNICATIONS. In order to promote
optimum coordination and facilitation of communications, Cerus and Baxter agree
to the placement of a Cerus employee (the "Cerus Employee") at Baxter's facility
where the Projects are managed, on a full-time basis, or such lesser amount of
time as Cerus makes such person available. Baxter shall provide suitable office
space for the Cerus Employee. Baxter shall inform the Cerus Employee of meetings
(including teleconferenced meetings) relating to the Cooperative Development
Work under this Agreement and the Platelet Agreement (together with any
evaluation or development work relating to New Technologies, other than any New
Technologies that the Management Board elects not to pursue, the "Pathogen
Inactivation Programs") and shall permit the Cerus Employee to attend such
meetings and otherwise to participate on a day-to-day basis in all issues
concerning the Pathogen Inactivation Programs; provided, however, that the Cerus
Employee shall not be permitted to attend meetings of Baxter's board of
directors or senior management team or meetings that are subject to Baxter
attorney-client privilege. The parties do not intend for the Cerus Employee to
have access to any Baxter proprietary information (other than information
relating to the Pathogen Inactivation Programs), and the Cerus Employee shall be
required to sign a Non-Employee Security Agreement in the form of Exhibit J
attached to this Agreement at or prior to the time such person arrives at
Baxter's facility. Cerus shall exercise complete and exclusive control over the
Cerus 


                                      19.


<PAGE>   26
Employee's conduct and performance and will pay and/or withhold all wages,
employee benefits, worker's compensation insurance and all applicable federal,
state and local taxes arising out of such employment. Cerus shall ensure that,
while present on Baxter's property, the Cerus Employee shall conform to all
Baxter rules and regulations regarding the conduct of visitors. Cerus shall, at
its sole expense, maintain insurance policies customary with those maintained
for Cerus' other employees, which policies shall cover Cerus and the Cerus
Employee under this Agreement, throughout the term of this Agreement. Any family
relocation and lodging expenses incurred by Cerus for the Cerus Employee will
not be subject to cost sharing hereunder.

4. EQUITY PURCHASE.

        4.1 BAXTER PURCHASE OF EQUITY IN CERUS. Baxter shall purchase equity in
Cerus according to the following terms and schedule:

               (a) Either purchase five million dollars ($5,000,000.00 U.S.) of
Cerus equity upon the occurrence of both:

                      (i) with respect to the Platelet Project, the receipt of
both (a) in the United States, F.D.A. approval to commence Phase III trials and
(b) in Europe, approval from a governmental authority to commence Phase III
trials (Buffy coats), and

                      (ii) the filing of an Investigational New Drug application
("IND") or Investigational Device Exemption ("IDE") or equivalent with the
F.D.A. to begin a Phase I study under the Red Cell Project, or comparable filing
in Europe under such Project (the "Tranche 3 Milestone") or, at Cerus' election,
purchase two million dollars ($2,000,000 U.S.) of Cerus equity upon the receipt
of both (i) in the United States, F.D.A. approval to commence Phase III trials
under the Platelet Project and (ii) in Europe, approval from a governmental
authority to commence Phase III trials (Buffy coats) under the Platelet Project
(the "Tranche 3a Milestone") and purchase three million dollars ($3,000,000
U.S.) upon the approval of an IND or IDE or equivalent by the F.D.A. or CE Mark
or equivalent approval in Europe under the Red Cell Project (the "Tranche 3b
Milestone") consisting of Common Stock at a purchase price equal to open market
price plus twenty percent (20%) if Cerus is publicly traded at the time of such
purchase or, if then privately held, Preferred Stock at the lesser of (i)
twenty-five dollars and ten cents ($25.10 U.S.) per share or (ii) fifty percent
(50%) premium over last private third-party financing round provided that this
clause (ii) shall apply only if there has been a third-party private financing
round of at least five million dollars ($5,000,000) since the date of the last
equity purchase by Baxter pursuant to this Section 4.1. Such purchase will be
consummated and the purchase price paid not later than within fifteen (15) days
after such Tranche 3 Milestone, Tranche 3a Milestone or Tranche 3b Milestone, as
the case may be. The purchase price stated in clause (i) above, however, shall
be increased from $25.10 to twenty-seven dollars ($27.00 U.S.) if both the
Tranche 3a Milestone and Tranche 3b Milestone are achieved by January 31, 1998.
If a closing under this Section 4.1 has previously occurred at the $25.10 price,
the price per share shall be retroactively increased to $27.00, and Baxter shall
promptly make an additional payment to Cerus to yield an effective price of
$27.00 per share on such purchase. For the purposes of this Section, the
"Platelet Interim Determination" means the point in the clinical trials under
the Platelet Agreement set forth on Schedule C to this Agreement. As used in
this Section 4.1, "open market" means the average closing price of the Cerus
stock, as reported in the Wall Street Journal, for the thirty (30) trading days
prior to and including the trading day that is two (2) 


                                      20.


<PAGE>   27
trading days prior to the date the purchase is consummated. A "trading day" is a
day when the Cerus stock may be traded on the relevant exchange or over the
counter.

               (b) The purchase prices set forth above in Subsection (a),
excluding prices set by open market price, will be appropriately adjusted for
stock splits, stock dividends and the like.

               (c) The purchases of equity set forth above will be made in
accordance with an agreement substantially in the form of the Stock Purchase
Agreement in the form of Schedule G to this Agreement, with appropriate changes
to reflect share price, class and series of stock being purchased and to make
accurate representations and warranties as of the date of the subsequent equity
purchases; such changes shall not affect the equity purchase and sale
obligations hereunder. While it is anticipated that the parties will separately
execute and deliver such Stock Purchase Agreements and associated documents for
subsequent equity purchases, the obligation to purchase and sell equity as set
forth in this Section are enforceable obligations upon the signing of this
Agreement irrespective of whether there is a separate execution and delivery of
such Stock Purchase Agreements and associated documents. It is understood that
from and after the date of Cerus' initial public offering or other conversion of
Cerus' outstanding Preferred Stock to Common Stock, the shares purchased
hereunder will be shares of Cerus Common Stock. Prior to such time, the shares
purchased hereunder will be shares of Cerus Preferred Stock. Cerus will use
reasonable efforts to provide Baxter fifteen (15) days prior notice of the
expected date of achievement of milestones under Subsection (a).

               (d) Notwithstanding Subsection (a) above, in the event that any
purchase of equity pursuant to such subsection would cause Baxter to own in
excess of twenty and one-tenth percent (20.1%) of issued and outstanding voting
capital stock of Cerus, Cerus may limit such purchase of equity by Baxter to a
number of shares of voting capital stock that would cause Baxter to own not more
than twenty and one-tenth percent (20.1%) of such issued and outstanding voting
capital stock. Notwithstanding Subsection (a) above, in the event that Baxter at
any time owns in excess of twenty and one-tenth (20.1%) of the issued and
outstanding voting capital stock of Cerus, Cerus may limit Baxter's further
purchases of voting capital stock pursuant to such subsection. Nothing in this
clause (d) will limit or restrict Baxter's right to convert the Special
Preferred Stock in accordance with its terms.

               (e) Notwithstanding Subsection (a) above, in the event that any
purchase pursuant to such subsection would cause Baxter to own in excess of
nineteen and nine-tenths percent (19.9%) of issued and outstanding voting
capital stock of Cerus, Baxter may limit such purchase of equity to a number of
shares of capital stock that would cause Baxter to own not more than nineteen
and nine-tenths percent (19.9%) of the issued and outstanding voting capital
stock of Cerus; provided that in each such instance, upon the written request of
Cerus, Baxter shall pay to Cerus as a research and development payment an amount
equal to the difference between [...***...] and the dollar amount of capital
stock being purchased. Such research and development payment will be made to
Cerus on the date for consummation of purchase of such capital stock. Unless
Cerus notifies Baxter, as set forth below, that Cerus elects to repay to Baxter
the amount of such research and development payment, such research and
development payment will be treated as if Baxter had made an additional
contribution of cash to the Final Project Total Budget for the purposes of the
fourth sentence of Section 3.5 (allocated among then 

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ongoing Projects (except for the S59 FFP Project) in proportion to the size of
the then approved budget for each Project). (Such research and development
payment shall not, however, change the actual approved budget for any Project
nor Cerus' contribution thereto.) Cerus must notify Baxter in writing at the
time of such research and development payment whether or not Cerus elects to
repay to Baxter the amount of such research and development payment. If Cerus
notifies Baxter that Cerus elects to repay such amount, Cerus will, if such
amount is not earlier repaid, pay to Baxter fifty percent (50%) of the Revenue
Sharing Payments received by Cerus hereunder, until such amount is repaid. In
the event that Baxter makes any such research and development payment to Cerus
pursuant to this subsection (e), Cerus will grant to Baxter a warrant to
purchase capital stock of Cerus on the following terms: (i) the exercise price
will be the price per share to Baxter established under Subsection (a) above
(i.e., the subsection applicable to the then current Baxter equity purchase);
(ii) the term of the warrant shall extend until [...***...] (as defined in the
Platelet Agreement) in the U.S. or Europe of the first product developed under
the Platelet Agreement, but not to exceed [...***...] from the date such
research and development payment was made, subject to earlier termination in the
event of merger or acquisition of Cerus; and (iii) the number of shares subject
to the warrant shall be equal to [...***...]. The number of shares subject to
the warrant will be appropriately adjusted from time to time for stock splits,
stock dividends and the like. Repayment of the amount of the research and
development payment will not terminate the warrant.

        4.2 STANDSTILL BY BAXTER. Baxter agrees that it will not at any time,
nor will it permit any of its Affiliates to, without the prior written consent
of Cerus:

               (a)

                      (i) acquire, directly or indirectly, by purchase or
otherwise, of record or beneficially, other than by the transactions set forth
in Section 4.1 of this Agreement or conversion of the Special Preferred Stock,
any securities of Cerus or rights or options to acquire any securities from any
holder of such securities if after such acquisition (and giving effect to the
exercise of any such rights or options) Baxter and its Affiliates would own
capital stock of Cerus having twenty and one-tenth percent (20.1%) or more of
the voting power of the outstanding capital stock of Cerus; provided, however,
that subsequent reductions in the number of shares of outstanding voting capital
stock of Cerus (or rights or options therefor) shall not be deemed to have
caused a violation of this Section 4.2(a).

                      (ii) To the extent Baxter and/or its Affiliates owns,
beneficially or of record, securities of Cerus constituting twenty and one-tenth
percent (20.1%) or more of the voting power of the outstanding capital stock of
Cerus and such securities include securities of Cerus other than those purchased
pursuant to Section 4.1, Baxter and/or its Affiliates shall be deemed to own
"Prohibited Securities." By way of example, to the extent that exercise of the
conversion rights of the Special Preferred Stock might cause Baxter to own
twenty and one tenth percent (20.1%) or more of the voting power of the
outstanding capital stock of Cerus, the shares received on exercise of such
conversion rights would be "Prohibited Securities" to the extent of such excess.
Baxter agrees that neither it nor any of its Affiliates shall (and neither it
nor any of its Affiliates shall be entitled to) vote any Prohibited Securities
with respect to any matter subject to the vote or written consent of Cerus'
stockholders (provided, however, that the foregoing shall 

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                                      22.


<PAGE>   29
not be deemed to limit Cerus' remedies in the event that the Prohibited
Securities were acquired in violation of this Section); 

                      (iii) Baxter hereby covenants and agrees that it will
provide written notice to Cerus of any purchase, sale or other acquisition or
disposition, on the open market or in private transactions, by Baxter or any of
its Affiliates of any securities of Cerus (or if Baxter or such Affiliates shall
direct any third party to take any such actions on behalf of Baxter or such
Affiliates). Such notice shall be transmitted to Cerus by facsimile (with
telephonic notice) within three (3) business days after any such transaction on
the open market or within ten (10) business days after any such private
transaction, and shall specify the person or entity effecting the transaction,
the date of such transaction, the number of securities and the price per
security with respect to such transaction;

               (b) solicit proxies with respect to any securities of Cerus under
any circumstances for change in the directors or management of Cerus or relating
to merger or acquisition of the Company or deposit any securities of Cerus in a
voting trust or subject them to a voting agreement or other agreement of similar
effect (other than subjecting shares owned by Baxter to a revocable proxy);

               (c) initiate, propose or otherwise solicit any stockholder for
the approval of one or more stockholder proposals at any time, or induce or
attempt to induce any other person to initiate any stockholder proposal for
change in the directors or management of Cerus or relating to merger or
acquisition of the Company; or

               (d) take any action individually or jointly with any partnership,
limited partnership, syndicate, or other group or assist any other person,
corporation, entity or group in taking any action it could not take individually
under the terms of this Section 4.2.

        The preceding provisions of this Section 4.2 shall terminate in the
event (i) any Person (defined below) or 13D Group (defined below) other than an
Affiliate of Baxter) shall have commenced a tender offer for a majority of the
outstanding shares of Common Stock (including any other outstanding voting
securities) of Cerus or (ii) Cerus' Board of Directors (the "Board") shall
determine to (A) approve any transaction set forth in clause (i) immediately
preceding, (B) liquidate Cerus or sell all or substantially all of the assets of
Cerus to another person, (C) approve a merger or consolidation of Cerus with any
other person that would result in the voting securities of Cerus outstanding
immediately prior thereto continuing to represent less than a majority of the
combined voting power of the voting securities of Cerus or such surviving entity
outstanding immediately after such merger or consolidation or (D) sell to any
person a majority of Cerus' outstanding voting securities. In the event of any
determination by the Board pursuant to the immediately preceding clause (ii),
Cerus shall notify Baxter at least 15 days prior to the final approval of such
transaction, and any such Board determination shall be conditioned upon the
notification by Cerus of Baxter in compliance with this sentence. For purposes
of this Section 4.2, a "13D Group" means any group formed for the purpose of
acquiring, holding, voting or disposing of securities of Cerus that would be
required under the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), and the rules and regulations promulgated thereunder, to file a statement
on Schedule 13D with the (United States Securities Exchange Commission) as a
"Person" within the meaning of Section 13(d)(3) of the Exchange Act if such
group beneficially owned sufficient securities to require such a filing. All of
the provisions of 


                                      23.


<PAGE>   30
this Section 4.2 shall be reinstated and shall apply in full force according to
their terms in the event that: (x) if the preceding provisions of this Section
4.2 shall have terminated as a result of a tender offer, such tender offer (as
originally made or as extended or modified) shall have terminated (without
closing) prior to the commencement of a tender offer by Baxter or any of its
Affiliates that would have been permitted to be made pursuant to the preceding
provisions of this paragraph as a result of such third-party tender offer, (y)
any tender offer by Baxter or any of its Affiliates (as originally made or as
extended or modified) that was permitted to be made pursuant to the preceding
provisions of this paragraph shall have terminated (without closing), or (z) if
the preceding provisions of this Section 4.2 shall have terminated as a result
of a Board determination referred to in the preceding clause (ii), the Board
shall have determined not to take any of such actions (and no such transaction
considered by the Board shall have closed) prior to the commencement of a tender
offer by Baxter or any of its Affiliates that would have been permitted to be
made pursuant to the preceding provisions of this paragraph as a result of the
initial Board determination referred to in the preceding clause (ii), unless
prior to such Board determination not to take any of such actions, any of the
events described in the preceding clause (i) shall have occurred. Upon
reinstatement of the provisions of this Section 4.2, the preceding provisions of
this paragraph shall continue to govern (including, without limitation, those
that provide for the termination of the preceding provisions of this Section
4.2) in the event that any of the events described in the preceding clauses (i)
or (ii) shall occur. Upon the closing of any tender offer for, or acquisition by
Baxter or its Affiliates of, any securities of Cerus or rights or options to
acquire any such securities that would have been prohibited by the preceding
provisions of this Section 4.2 but for the provisions of this paragraph, all
provisions of this Section 4.2 shall terminate.

5. SUPPLY OF CERUS COMPOUND AND SYSTEM MANUFACTURING.

        5.1 CERUS RESPONSIBILITIES. Cerus shall at all times use commercially
reasonable efforts to supply, or have supplied, Baxter's demand for the Cerus
Compounds and New Technology Compounds that the Management Board determines are
to be supplied by Cerus, used in each System, and S59 removal devices for S59
FFP Systems. The Parties shall agree in good faith upon a forecasting, order,
supply and delivery mechanism for the Cerus Compounds, such New Technology
Compounds and S59 removal devices for S59 FFP Systems. All Cerus Compounds, New
Technology Compounds and S59 removal devices for S59 FFP Systems supplied by
Cerus shall comply with the requirements for such compounds and components
established pursuant to Section 5.5 of this Agreement.

        5.2 BAXTER RESPONSIBILITIES. Baxter shall be responsible for all aspects
relating to scale-up, production, marketing and distribution of each System, but
not including manufacturing of the Cerus Compounds, New Technology Compounds
that the Management Board determines are to be provided by Cerus or S59 Removal
Devices for S59 FFP Systems. Such products shall meet the requirements for
Systems as finally approved in writing by the Management Board. Any change in
requirements must be approved in writing by the Management Board. Such
requirements shall include a provision that such products be made according to
Good Manufacturing Practices in a facility licensed by the FDA (or if Baxter
shall elect to manufacture outside the United States) other applicable
regulatory authority.


                                      24.


<PAGE>   31
        5.3 INSTRUMENT PRODUCTION. Baxter shall tool and scale up the production
model of any Instrument needed for each System. Baxter shall be responsible for
production and manufacture of the Instrument and associated software of each
System.

        5.4 SYSTEM SPECIFICATIONS. Baxter's manufacture of each System shall be
in accordance with Systems Specifications as finally approved in writing by the
Management Board. Any change in Systems Specifications must be approved in
writing by the Management Board.

        5.5 CERUS SPECIFICATIONS. Cerus shall supply Cerus Compounds, and those
New Technology Compounds that the Management Board shall determine are to be
supplied by Cerus, in Bulk Form to Baxter to be used as a component of a System
and Baxter shall obtain Cerus Compounds and such New Technology Compounds to
meet its requirements of inactivation compounds (other than Baxter Compounds and
those New Technology Compounds that the Management Board determines are to be
provided by Baxter) for use within the Field. Such Cerus Compounds and New
Technology Compounds shall meet the specifications for Cerus Compounds and New
Technology Compounds as finally approved in writing by the Management Board. Any
change in specifications for such Cerus Compounds or New Technology Compounds
must be approved in writing by the Management Board. Such specifications shall
include a provision that Cerus Compounds, and New Technology Compounds that the
Management Board determines shall be supplied by Cerus, be made according to
Good Manufacturing Practices in a facility licensed by the FDA or (if Cerus
shall elect to manufacture such compounds outside the United States) other
applicable regulatory authority.

        5.6 SOURCE OF SUPPLY. In the event Baxter recommends that Cerus change
Cerus' source of raw materials or Cerus Compound because of actual or
anticipated irregularity of supply, or failure to meet specifications and a
viable alternative source of supply is available, Cerus will support Baxter in
Cerus' obtaining such alternate source to the extent commercially reasonable.

        5.7 FAILURE OF CERUS TO MEET BAXTER REQUIREMENTS. To the extent that
Cerus cannot meet Baxter's requirements for Cerus Compounds, Baxter shall be
free to obtain Cerus Compounds from a third party. Cerus agrees to provide the
third party that Baxter selects with the necessary information and Cerus
Know-How to allow the third party to make the Cerus Compounds.

        5.8 SYSTEM IMPROVEMENTS. During the term of this Agreement, as approved
by the Management Board, the Parties will cooperate in making improvements to
each System to meet changing market needs, to yield manufacturing cost
reductions or make quality improvements. The costs for such System Improvements
of Inactivation Packages shall be budgeted by the Management Board and subject
to cost sharing pursuant to Section 3.5 and shall be added to the Final Project
Total Budget. Notwithstanding the foregoing, Cerus will be responsible for
[...***...] and Baxter will be responsible for [...***...] of the cost of System
Improvements for the S59 FFP Systems, such obligation, however, being subject to
mutual agreement to undertake such System Improvement.

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<PAGE>   32
6.      MARKETING AND DISTRIBUTION RIGHTS: EXCLUSIVE DISTRIBUTION RIGHTS.

        6.1 COMMERCIALIZATION. Baxter shall use commercially reasonable efforts
to market and sell Systems developed under this Agreement in those countries of
the world in which the Management Board determines that such Systems should be
marketed and sold. The parties agree that it is desirable to obtain a
distribution partner in Japan for S59 FFP Systems and agree to cooperate to
obtain such distribution partner. A distribution partner for S59 FFP Systems in
Japan obtained through such cooperative efforts is referred to herein as a Joint
Japan FFP Distribution Partner. In the event that any agreement is arranged with
a Joint Japan FFP Distribution Partner, or otherwise with a distribution partner
in Japan, Cerus will have the right to retain any up-front or milestone payments
paid by such party for distribution rights for S59 FFP Systems. In the event
that a Joint Japan FFP Distribution Partner is not obtained through such
cooperation on or before [...***...], Cerus shall have the right to terminate
any sales or distribution rights of Baxter with respect to S59 FFP Systems in
Japan, and may take unilateral action to obtain a distributor for that product
in Japan, and such distribution will be considered distribution by Cerus
pursuant to Section 6.5 hereof.

        6.2 MEETINGS CONCERNING MARKETING. The Management Board shall meet from
time-to-time to discuss and approve marketing strategies in order to optimize
customer acceptance and effective promotion of each System. All final plans and
strategies regarding System marketing, distribution and pricing shall be
established by the Management Board reasonably and in good faith. Baxter shall
follow the plans and strategies established by the Management Board. The
Management Board will review the marketing plans and strategies, including
pricing, from time to time in the light of market conditions. Day-to-day
marketing and sales decisions will not be made by the Management Board; Baxter
will be responsible to make day-to-day marketing and sales decisions using its
best efforts to maximize Net Sales in the interest of both parties.
Notwithstanding the foregoing, it is understood and agreed that Baxter and Cerus
will not discuss marketing, distribution or pricing of products in any country
if Baxter and Cerus are marketing, or have plans to market, competing products
in such country.

        6.3 EXCLUSIVE RELATIONSHIP. The parties acknowledge that, except as
permitted under Sections 3.8(b) and 3.8(c), the relationship established by this
Agreement shall be the sole vehicle for exploitation by either party of products
and services in the Field. Accordingly, each party agrees that, except as
permitted under Sections 3.8(b) and (c), it will not research, develop or market
inactivation/decontamination products or services in the Field, including
without limitation products which compete indirectly or directly with the
Systems developed and marketed under this Agreement, except under and in
accordance with the terms of this Agreement. The foregoing sentence shall not in
any event, however, prevent either party from independently investigating or
researching New Technology to the extent reasonably necessary for presentation
of such New Technology to the Management Board under Paragraph 3.8(a).
Notwithstanding the foregoing, nothing in this Agreement shall prevent or
restrict Baxter from independently developing and marketing systems for
inactivation of pathogens in FFP using methylene blue.

        6.4 COMPETING PRODUCTS. In the event Baxter markets within a specific
country or territory an inactivation/decontamination product that competes
directly with a specific system 

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                                      26.


<PAGE>   33
developed under this Agreement, Baxter's rights under this Agreement shall
become co-exclusive with Cerus, or in the case of S59 FFP Systems may be
terminated by Cerus, for the specific System in that specific country or
territory only, allowing Cerus to market, sell and distribute the System itself
within the specific country or territory or, if Cerus chooses, through a single
Approved Distributor or Approved Distributors within the specific country or
territory. The sharing of Premium shall be adjusted according to Section 7.3.
With respect to S59 FFP Systems, Cerus will notify Baxter upon receipt of
Regulatory Approval of an S59 FFP System in any country. Baxter will notify
Cerus in writing within ninety (90) days after receipt by Baxter of notice of
Regulatory Approval of an S59 FFP System in a country whether or not Baxter
intends to distribute the S59 FFP System in such country. If Baxter is then
selling a competing system based on methylene blue in such country, Baxter will
have one year from the date receipt by Baxter of notice of such Regulatory
Approval to cease selling such methylene blue-based system in such country. If
Baxter ceases within such period to sell such methylene blue-based system in
such country, the first sentence of this Section shall not apply with respect to
Baxter's distribution rights in such country.

        6.5 COMMENCEMENT, CESSATION OF MARKETING. If (a) according to the
Management Board, Baxter (through its own efforts or those of its distributors)
has not marketed a specific System within a specific country or territory
following Market Launch within a reasonable time, but not less than one year nor
more than three years from Market Launch, or (b) after commencement of marketing
of a specific System in a particular country or territory, Baxter shall cease
marketing (or be prevented from marketing by governmental action concerning
Baxter) of such System in such country or territory in the manner required under
this Agreement, Cerus shall have exclusive rights to market that specific System
in that specific country or territory only, allowing Cerus to market, sell and
distribute the System itself within the specific country or territory, or if
Cerus chooses, through an Approved Distributor or Approved Distributors within
the specific country or territory. The sharing of Premium shall be adjusted
according to Section 7.3. If, according to the Management Board, Cerus (through
its own efforts or those of its distributors) has failed to gain a sufficient
market share for a particular System within a specific country or territory
within three (3) years after Cerus has obtained marketing rights in such country
or territory, or to gain or maintain sufficient market share in such country at
any time thereafter, or has ceased marketing of a specific System (other than
S59 FFP Systems) in any country or territory, Cerus' rights under this Agreement
shall become co-exclusive with Baxter, for that specific System in that specific
country or territory, allowing Baxter to market, sell and distribute the System
itself within the specific country or territory or, if Baxter chooses, through a
single Approved Distributor or Approved Distributors within the specific country
or territory.

        6.6 ACHIEVEMENT OF MARKET SHARE. If, according to the Management Board,
Baxter (through its own efforts and those of its distributors) has not gained a
sufficient market share for a particular System within a specific country or
territory within three (3) years following Market Launch, or has not gained or
maintained sufficient market share in such country at any time thereafter,
Baxter's rights under this Agreement shall become co-exclusive with Cerus, or in
the case of S59 FFP Systems may be terminated by Cerus, for that specific System
in that specific country or territory, allowing Cerus to market, sell and
distribute the System itself within the specific country or territory or, if
Cerus chooses, through a single Approved Distributor or Approved Distributors
within the specific country or territory. The sharing of Premium shall be
adjusted according to Section 7.3.


                                      27.


<PAGE>   34
        6.7 SUPPLY OF BAXTER GOODS. Baxter shall provide the necessary Baxter
disposables, Blood Pack Units(R), Instruments, Baxter Compounds, New Technology
Compounds that the Management Board determines will be provided by Baxter, and
other components necessary for Cerus, or Cerus' Approved Distributor, to sell
Systems under Sections 6.1, 6.5 and 6.6. Cerus shall forecast its needs for such
Baxter disposables, apheresis kits, Blood Pack Unit(R), Instruments, Baxter
Compounds, New Technology Compounds that the Management Board determines shall
be supplied by Baxter, and other components under Sections 6.1, 6.5 and 6.6.
Baxter's Cost of Goods/Base Revenue under this section shall be reimbursed under
Section 7.3, except with respect to Instruments, as provided in this Section.
Baxter shall not, however, be obligated to develop, reconfigure, modify, qualify
or seek Regulatory approval for any disposables, apheresis kits, Blood Pack
Units(R), Instruments, Baxter Compounds, New Technology Compounds that the
Management Board determines shall be supplied by Baxter, or other components
supplied to Cerus or Cerus' Approved Distributor under this Section. If Cerus
distributes S59 FFP Systems in any country, Cerus will be responsible in such
country for placement with customers of Instruments that are solely for use with
S59 FFP Systems. Cerus will pay to Baxter [...***...], if such Instruments are
manufactured by a third-party supplier, or [...***...], if such Instruments are
manufactured by Baxter. In the event Cerus terminates Baxter's distribution
rights for S59 FFP Systems with respect to a particular country, and Cerus or
another distributor takes over distribution of such Systems, Cerus will purchase
from Baxter any Instruments owned by Baxter and placed with customers in such
country solely for use with S59 FFP Systems, and Cerus will pay Baxter's book
value for any such Instruments.

        6.8 REQUALIFICATION. In the event Cerus obtains distribution rights
under Section 6.1, 6.5, 6.6, 12 or 16, or in the event Baxter does not supply
sufficient goods under Section 6.7 to meet Cerus' needs (without limiting
Baxter's obligation to supply such goods) Cerus may, or may license third
parties to, make, have made, use, sell and have sold products using the Cerus
Compounds, Baxter Compounds or New Technology Compounds, or under the Cerus
Patents or Cerus Know-How or patents or know- how pertaining to New Technology
to which rights have been acquired pursuant to Section 3.8, and under any
patents or know-how under which Cerus is licensed pursuant to Section 8.5(b) and
Section 8.6 hereof, for the use and in the particular country or countries for
which Cerus has distribution rights, provided that such products are qualified
for regulatory approval on Cerus' or such third party's own system.

        6.9 MANAGEMENT BOARD ACCESS TO AND REVIEW OF MARKETING AND DISTRIBUTION
INFORMATION. A party marketing and distributing products under this Agreement
will provide to the Management Board all information in such party's possession
as the Management Board may reasonably require from time to time to review and
make decisions concerning marketing and distribution, including without
limitation breakdown and substantiation of any data provided pursuant to Section
13 of this Agreement. If the information requested of a party is information
that is not normally collected by the party, and requires substantial additional
expense of such party to collect and provide, such additional expense shall be
borne equally by the parties.

        6.10 BAXTER TERMINATION OF DISTRIBUTION FOR S59 FFP SYSTEMS. Baxter may
elect upon twenty-four (24) months' prior written notice to Cerus to terminate
Baxter's right and obligation to distribute S59 FFP Systems in a particular
country, provided that after receipt of such notice, Cerus may earlier terminate
such right and obligation in such country.

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                                      28.


<PAGE>   35
        6.11 BAXTER TERMINATION OF SUPPLY OF GOODS FOR S59 FFP SYSTEMS. In the
event that Baxter's distribution rights for S59 FFP Systems terminate for any
reason, Baxter may thereafter elect upon [...***...] months' prior written
notice to terminate its right and obligation to supply goods to Cerus pursuant
to Section 6.7 hereof. Baxter will provide reasonable assistance during such
[...***...] month period to assist Cerus to make the transition to another
supplier or suppliers. In addition, Baxter will continue, even after such
[...***...] month period, to supply components that Cerus is unable to obtain
from third parties due to Baxter proprietary rights or that are required to
maintain regulatory validation for the Cerus S59 FFP Systems; such components
will be supplied by Baxter at [...***...] for such components. Cerus will use
due diligence to seek regulatory validation of substitute components during such
[...***...] month period. Following such termination, Baxter shall cease to
receive any Revenue Sharing Payments with respect to S59 FFP Systems.

        6.12 CERUS TERMINATION OF BAXTER MANUFACTURING RIGHTS FOR S59 FFP
SYSTEMS. In the event that, during the scale-up or manufacturing stages for the
S59 FFP Project, Cerus unilaterally terminates the S59 FFP Project or Baxter's
manufacturing rights and obligations for S59 FFP Systems, other than for breach
of this Agreement by Baxter, then during the period between receipt by Baxter of
Cerus' notice of intent to terminate and the actual date of termination, Baxter
will use its best efforts, in consultation with Cerus, to reduce inventory and
limit commitments to suppliers and to wind down such operations. Following the
actual date of termination, Cerus will pay to Baxter Baxter's out of pocket
costs with respect to raw materials, work-in-process and finished goods
purchased or ordered on non-cancellable orders that cannot be disposed of or
used for other purposes, and Baxter will convey title to such goods to Cerus.
Cerus will also pay to Baxter reasonable wind-down costs of Baxter personnel
that were engaged by Baxter solely to carry out such activities and who cannot
be reassigned to other duties at Baxter. Such personnel costs shall not exceed
two weeks salary and benefits for any such individual. At Cerus' request, Baxter
will provide to Cerus books and records reflecting any costs for which Baxter is
seeking reimbursement under this Section.

        6.13 CERUS TERMINATION OF DISTRIBUTION RIGHTS FOR S59 FFP SYSTEMS. In
the event that following Market Launch for the S59 FFP Project, Cerus
unilaterally terminates Baxter's distribution rights hereunder with respect to
S59 FFP Systems, other than for breach of this Agreement by Baxter, Cerus will
provide Baxter not less than [...***...] months written notice of such
termination. During such period, the parties will cooperate to sell any
inventory held by Baxter. At the end of such period, Cerus will purchase any
inventory that has an acceptable shelf life at a purchase price equal to
Baxter's Cost of Goods. Cerus will be entitled to credit such purchase price
against any Cerus obligation under Section 7.3 hereof to Baxter arising from
Cerus' sale of inventory. At Cerus' request, Baxter will provide to Cerus books
and records reflecting any costs for which Baxter is seeking reimbursement under
this Section. In the event that agreements with customers entered into prior to
receipt of such Cerus notice of termination have contractual commitments to
customers extending beyond the termination date, Cerus shall, at its election on
a customer-by-customer basis, (a) permit Baxter to continue to supply S59 FFP
Systems to such customer beyond the termination date, (b) assume Baxter's supply
obligations under such contractual commitments, or (c) pay any penalties owing
to the customer to terminate such contractual commitments.

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                                      29.


<PAGE>   36
7.      REVENUE SHARING.

        7.1 REVENUE SHARING PAYMENTS. In consideration of the Cooperative
Development Work to be undertaken and other obligations set forth herein, the
parties agree to share Net Sales as follows: Subject to the provisions of
Sections 3.5, 3.7(a), 7.2, 7.3, 7.4, and 12, no later than sixty (60) days after
the first and all subsequent calendar quarters following the Market Launch of
the System, (a) Baxter shall pay to Cerus, with respect to Net Sales in such
calendar quarter, a sum equal to: (1) Cerus' Cost of Goods/Base Revenue; and (2)
fifty percent (50%) (or such other percentage as is established pursuant to
Section 3.5 hereof) for all products other than S59 FFP Systems, and
Seventy-Five percent (75%) for S59 FFP Systems, of the Premium during such
calendar quarter ("Revenue Sharing Payments"), and (b) Baxter shall retain for
itself the balance of the proceeds of Net Sales of Systems shipped during such
Calendar Quarter. On each such date a party that has received in such calendar
quarter a royalty, license fee or other consideration for licensing or
sublicensing rights hereunder shall pay to the other party the amount due to
such party under Section 7.4. The Revenue Sharing Payments due and payable
hereunder shall be computed for each calendar quarter in the currency in which
the sale was made, but shall be definitively discharged by payment to Cerus in
U.S. dollars converted from such currency using the average of spot rates for
such currency for the last business day of the second and third months of such
quarter and of the first month of the subsequent quarter, as quoted in the Wall
Street Journal (or such other mutually agreeable financial publication of
international circulation or rates published by Baxter's corporate treasury, if
mutually agreed).

        7.2 BAXTER SOURCING CERUS COMPOUNDS. In the event Baxter sources the
Cerus Compounds from an alternate source, Baxter shall retain for itself the
Cost of Goods/Base Revenue for the Cerus Compounds in the Systems shipped during
such calendar duration.

        7.3 CERUS AS SELLER OF SYSTEMS. In the event Cerus, or an Approved
Distributor appointed by Cerus, is the seller of the Systems under Sections 6.1,
6.5, 6.6 or Section 12, Cerus shall retain for itself its Cost of Goods/Base
Revenue, and the Marketing and Administrative Expenses, and pay to Baxter,
Baxter's Cost of Goods/Base Revenue and the percentage of Premium received by
each of the parties will equal the percentage contributed by such party to the
sum of (a) cash contributed to the Final Project Total Budget, plus (b) Noncash
Contribution to the Project, provided that for the purposes of computations
under this Section, Baxter's Noncash Contribution shall be reduced by (i) fifty
percent (50%) if such sales are made pursuant to Section 6.6, or (ii) by
seventy-five percent (75%) if such sales are made pursuant to Section 6.1, 6.5,
or Section 12. In the event that Cerus purchases any components from Baxter, as
provided in Section 6.7, Baxter's share of the Premium split shall be not less
than fifty percent (50%) of Baxter's Cost of Goods for such components, except
with respect to Instruments, as provided in Section 6.7. For the purpose of
clarification, with respect to S59 FFP Systems, expenditures by Cerus and
unreimbursed expenditures by Baxter after December 31, 1997 will be considered
part of such party's cash contribution to the S59 FFP Final Project Total
Budget.

        7.4 LICENSING OF RIGHTS ARISING UNDER THIS AGREEMENT. In the event
either Cerus (pursuant to Section 6.8 hereof) or Baxter (pursuant to Section 8.4
hereof) or Cerus and Baxter jointly (pursuant to a determination of the
Management Board) licenses or sublicenses to a third party rights arising under
this Agreement, all royalties, license fees and other consideration received
from such licensing or sublicensing (excluding research or development payments)
shall be shared by the parties according to the percentage of the sum of (a)
funding by each party 


                                      30.


<PAGE>   37
in the Final Project Total Budget (or such lesser amount as shall have been
expended by Baxter and Cerus to enable the parties to license or sublicense the
rights hereunder and to comply with their development obligations under the
license or sublicense agreement), plus (b) Noncash Contribution to such Project
made by each party, provided that for the purposes of this Section, Cerus' and
Baxter's Noncash Contributions will be equitably adjusted to reflect the
relative contribution of Cerus Patents and Cerus Know-How and Baxter Patents and
Baxter Know-How to the rights being licensed or sublicensed, but in all events
Baxter's Noncash Contribution shall be reduced by not less than seventy-five
percent (75%). In the event such license or sublicense to a third party is
solely to rights to a New Technology acquired jointly by Baxter and Cerus
pursuant to Section 3.8(a), and not to rights with respect to any Cooperative
Development Work, Baxter and Cerus shall share equally, or in such other
proportion as Baxter and Cerus shall agree, all royalties, license fees and
other consideration received from such licensing or sublicensing.
Notwithstanding the foregoing, Cerus will not have any obligation to pay any
royalty, license fee or other consideration with respect to any licensing by
Cerus to third parties pursuant to the rights of Cerus under Section 8.5(a) of
this Agreement.

        7.5 DISTRIBUTOR SALES. In the event that either party sells Inactivation
Packages or Integrated Inactivation Sets through a distributor, other than sales
by Cerus of such products for S59 FFP, Net Sales shall be computed as set forth
in paragraph (c) of the definition of Net Sales, and the Distributor Portion
will not diminish the Revenue Sharing Payment receivable by the other party.

8.      PATENTS, KNOW-HOW, LICENSE GRANTS.

        8.1 CERUS SOLE OWNERSHIP. Any Cerus Project Inventions shall be assigned
to and owned by Cerus.

        8.2 BAXTER SOLE OWNERSHIP. Any Baxter Project Inventions shall be
assigned to and owned by Baxter.

        8.3 JOINT OWNERSHIP.

               (a) Cerus and Baxter each agrees to take all reasonable steps to
maximize the opportunity for patent protection of inventions made in the course
of this Agreement, including, without limitation, inventions that are
improvements of inventions covered by the Baxter Patents and Cerus Patents.

               (b) Joint Inventions shall be assigned to and owned by Baxter and
Cerus jointly, except as set forth below in this Section 8.3(b).

                        (i)     Those inventions which would be unpatentable,
                                under 35 U.S.C. Section 103, over Cerus-owned
                                patents or patent applications that qualify as
                                prior art solely under 35 U.S.C. Section 102(f)
                                or 35 U.S.C. Section 102(g) (other than patents
                                or patent applications commonly owned by Cerus
                                and Baxter) shall be owned by, and are hereby
                                deemed assigned to, Cerus.

                        (ii)    Those inventions which would be unpatentable,
                                under 35 U.S.C. Section 103, over Baxter-owned
                                patents or patent applications that qualify 


                                      31.


<PAGE>   38
                                as prior art solely under 35 U.S.C. Section
                                102(f) or 35 U.S.C. Section 102(g) (other than
                                patents or patent applications commonly owned by
                                Baxter and Cerus) shall be owned by, and are
                                hereby deemed assigned to, Baxter.

               (c) The parties agree that any Joint Invention previously
assigned under the terms of this Agreement as in effect prior to the First
Amendment Effective Date shall be re-assigned in accordance with the terms of
this Agreement as amended and restated on the First Amendment Effective Date.

               (d) Any Contractor Inventions of which either Baxter or Cerus
gains ownership shall be considered Joint Inventions with ownership assigned as
provided in Section 8.3(b), irrespective of whether the contract with the
Contractor specifies Baxter or Cerus, or Baxter and Cerus jointly, as the
assignee; provided, however, that any Contractor Inventions reading on S59 FFP
Systems will be assigned to and solely owned by Cerus, unless such Contractor
Inventions read on both S59 Systems and systems developed under the Platelet
Agreement, in which case ownership of such Contractor Inventions will be
assigned as provided in the Platelet Agreement. Each party agrees to execute
such additional documents as may be necessary to evidence or effectuate such
ownership or assignment. To the extent any such contract conveys any rights by
license, the recipient of such license rights (whether Cerus or Baxter) will use
its best efforts to obtain the right to assign an equal interest in, or
sublicense, such rights to the other party, and if obtained, such rights shall
be granted to the other party. If for any reason, such rights to equal interest
or sublicense can not be obtained, Cerus and Baxter will nonetheless arrange
between themselves for Cerus and Baxter to share the benefits of such rights in
a manner consistent with the terms of this Agreement. The parties agree that any
Contractor Invention previously assigned under the terms of this Agreement that
were in effect prior to the First Amendment Effective Date shall be re-assigned
in accordance with the terms of this Agreement as amended and restated on the
First Amendment Effective Date. Notwithstanding the foregoing, any rights
obtained by license with respect to S59 FFP Systems will be owned solely by
Cerus without any obligation to assign to Baxter or make other arrangements for
the benefit of Baxter, unless such rights read on both S59 FFP Systems and
systems developed under the Platelet Agreement, in which case ownership of such
rights will be assigned as provided in the Platelet Agreement.

               (e) Within the Field, the parties shall exploit any Joint Patents
solely for the development, sale or licensing of Systems pursuant to this
Agreement.

        8.4 LICENSE.

               Subject to the terms and conditions of this Agreement, for
Systems whose manufacture, use or sale is covered by a claim of a Cerus Patent,
or which use Cerus Know-How, Cerus hereby grants Baxter an exclusive, paid-up,
royalty free (except as provided herein) license, with the right to sublicense
(if such sublicense is approved in advance by the Management Board), under Cerus
Patents and Cerus Know-How to make, have made, import, sell, offer for sale or
have sold such Systems, and to use such Systems solely for promotion and sale
thereof, worldwide, solely for use in the Approved Project Field.
Notwithstanding the foregoing, for any country or territory where such marketing
rights become co-exclusive or exclusive to Cerus pursuant to Sections 6.1, 6.5
or 6.6 of the Agreement, such license shall 


                                      32.


<PAGE>   39
automatically become co-exclusive with Cerus, or the rights shall revert
exclusively to Cerus, as the case may be, for such country or territory. Except
as set forth herein in Section 5.7, such license shall exclude the right to make
or have made Cerus Compounds. As to Cerus Compounds, such license shall be
limited to the Cerus Compounds that are selected by the Management Board for a
specific Project within the Approved Project Field. Notwithstanding anything in
this Section or elsewhere in this Agreement, Baxter shall not have any license
or distribution rights in or to any Cerus Patent or Cerus Know-How to the extent
relating to (a) the inactivation of bacteria, viruses, parasites or other
pathogens through use of compounds other than psoralens, ALE compounds or New
Technology Compounds, or (b) use outside the Approved Project Field, except as
provided in Section 8.6 of this Agreement.

        8.5 CERUS RIGHTS.

               (a) Baxter and Cerus have previously entered into a letter
agreement dated January 18, 1996 Re Non-Exclusive License for Plasma Derivatives
a copy of which is attached hereto as Schedule D (the "Plasma Derivatives
Letter"). The Plasma Derivatives Letter is not superseded by this Agreement. For
the purposes of clarity, the parties agree that the terms of the Plasma
Derivatives Letter apply to source plasma and recovered plasma for fractionation
in the same manner as they apply to plasma derivatives and recombinant
equivalents thereof, all of which shall be considered to be outside of the
Field, notwithstanding any other provision of this Agreement.

               (b) The license to Baxter set forth above is subject to the right
retained by Cerus to grant licenses to third parties under Cerus Patents and
Cerus Know-How, and exercise other rights, as provided in Section 6.8 of this
Agreement. Baxter further grants to Cerus paid-up, royalty-free (except as
provided herein) license, with right to sublicense (a) co-exclusive in the
Field, to any Baxter Project Patents or Baxter Know-How developed in the course
of the Cooperative Development Work or Platelet Project, and (b) non-exclusive
in the Field to any Baxter Patents or Baxter Know-How otherwise embodied or used
within a System or a system developed under the Platelet Agreement; solely for
the purposes of granting licenses and exercising other rights pursuant to
Sections 6.1, 6.5, 6.6, 6.7, 6.8 and 8.5 or exercising Cerus' rights under
Section 12 or 16 of this Agreement, including without limitation the right to
make, have made, and use, sell or have sold any components of a System. This
clause (b) shall exclude, however, any Baxter proprietary materials or Baxter
proprietary configuration of blood bags and associated tubes and connections, or
Baxter proprietary processes to manufacture any of the same, unless Baxter shall
consent in writing to license of the same to Cerus.

        8.6 CROSS-LICENSE AS TO INSTRUMENTS AND COMPOUND REMOVAL DEVICES;
            EXPLOITATION OF JOINT INVENTIONS OUTSIDE THE FIELD.

               (a) Cerus hereby grants to Baxter, and Baxter hereby grants to
Cerus, a worldwide, non-exclusive, paid-up, royalty-free license, with right to
sublicense, to make, have made, import, and use, sell, offer for sale, or have
sold, outside the Field, products under any patents and know-how of the granting
party used or embodied in any Instrument or in any compound removal device
developed under this Agreement or the Platelet Agreement.

               (b) Either party may exploit any Joint Invention and rights to
any Joint Patent outside the Field subject to an obligation to pay the other
party a reasonable royalty to be 


                                      33.


<PAGE>   40
negotiated in good faith, taking into account the parties' relative
contributions to the making of such invention, and, failing agreement on such
royalty, to be determined by arbitration pursuant to Section 3.2(d) hereof. Such
royalty will be paid by a party irrespective of whether sole ownership of such
Joint Invention or Joint Patent is assigned, pursuant to Section 8.3(b), 8.3(c)
or 8.3(d), to such party or to the other party. Such royalty obligations shall
not apply to the exercise of the rights specifically provided in Section 8.6(a)
above. Notwithstanding the foregoing or Section 8.6(c), any exploitation by a
party of a Joint Invention in the Field shall be made solely either through a
System developed pursuant to the Cooperative Development Work and subject to
revenue sharing as provided herein.

               (c) If either party is assigned sole ownership of a Joint
Invention pursuant to Section 8.3 hereof, that party hereby grants to the other
party a worldwide, irrevocable, non-exclusive paid-up (except for the royalties
provided for in Section 8.6(b)) license, with right to sublicense, to make, have
made, import, and use, sell, offer for sale, or have sold products practicing
such invention and under any associated patent rights.

        8.7 EXCLUDED PRODUCTS. The term Excluded Product means any product in
the Field that Baxter, in its sole discretion, specifically notifies Cerus in
writing that Baxter has no interest in developing and marketing. In the event
that Cerus proposes in writing a product for development under the Cooperative
Development Work, Baxter will consider such proposal in good faith and will
notify Cerus in writing if Baxter has no interest in developing and marketing
such product in the reasonably foreseeable future. Notwithstanding any other
provision of this Agreement, all rights and licenses hereunder as to any
Excluded Product shall revert to Cerus, including without limitation the right
to make, have made, and use, sell and have sold the Excluded Product. Cerus
shall not have any obligation to account to Baxter for any proceeds from sale of
any Excluded Product.

        8.8 NOTICE OF SOLE RIGHTS. After the Effective Date of this Agreement, a
party asserting sole ownership of any patent rights or know-how in the Field
developed pursuant to the Cooperative Development Work shall provide reasonable
notice to the Patent Committee of its intention to seek patent protection or to
assert proprietary interest in such Know-How. The Patent Committee shall have
the right to a reasonable opportunity to review and comment on such assertions
prior to patent applications being filed.

        8.9 OTHER AGREEMENTS. Cerus shall not terminate, alter or amend the
terms of the following agreements in a manner that would limit Cerus' or
Baxter's rights under this Agreement without the prior written approval of
Baxter: The Technology Transfer Agreement and the License Agreement between
Cerus and HRI Research, Inc. each dated December 13, 1991. Baxter shall respond
within thirty (30) days of receipt of written proposed changes to such
agreements. Baxter's approval of proposed changes shall not be unreasonably
withheld.

        8.10 REGULATORY FILES. Baxter and Cerus shall each have full access to
all materials filed and correspondence with the FDA and other regulatory
agencies in connection with the Cooperative Development Work and each System,
and shall be entitled to use and rely on such materials with respect to any
regulatory approvals for a product sought by either, whether or not such product
relates to this Agreement, provided that Baxter shall be entitled to use or rely
on any such materials relating to regulatory approvals sought for the S59 System
only for the purpose of developing and marketing Systems pursuant to this
Agreement and the Platelet 


                                      34.


<PAGE>   41
Agreement. In the event that product registration is in the name of Baxter in
any country and Cerus obtains marketing rights for such product in such country,
then Baxter will, at Cerus' expense, cause the product to be co-registered in
Cerus' name or take other steps so that Cerus may market and sell the product
under such registration. Promptly following the First Amendment Effective Date,
Baxter will take all actions, including execution and filing of all documents,
necessary or appropriate to transfer to Cerus all applications and filings
relating to regulatory approvals sought for the S59 FFP System.

        8.11 RIGHTS UNDER GOVERNMENT-SPONSORED RESEARCH. Any licenses hereunder
to any "subject invention," if any, as defined in 35 U.S.C. Section 201, shall
be subject to the rights of the United States Government under 35 U.S.C.
Section, 200 et seq.

9.      PROSECUTION OF PATENT RIGHTS.

        9.1 CERUS PATENTS. Cerus shall have the right but no obligation to
timely prepare, file, prosecute and maintain, under its exclusive control and at
its expense, Cerus Patents.

        9.2 BAXTER PATENTS. Baxter shall have the right but no obligation to
timely prepare, file, prosecute and maintain, under its exclusive control and at
its expense, Baxter Patents.

        9.3 JOINT PATENTS. The parties shall jointly engage counsel for the
purpose of timely preparing, filing, prosecuting and maintaining Joint Patents;
provided, however, that if a Joint Patent is assigned to one party or the other
pursuant to Section 8.3 hereof, the party to whom such patent is assigned shall
employ counsel subject to the other party's right to approve such counsel, which
approval shall not be unreasonably withheld. The parties shall jointly control
the preparation, filing, prosecution and maintenance of Joint Patents and all
expenses relating there to shall be subject to cost sharing pursuant to Section
9.6 hereof. Whenever possible, the parties shall file internationally under the
Patent Cooperation Treaty and/or the European Patent Convention in order to
minimize expenses. The party or parties who engage counsel to prepare or
prosecute Joint Patents shall advise such counsel, at the time of engagement,
that such counsel represents both parties.

        9.4 PRIOR ART; REVIEW AND COMMENT. Each party shall cooperate with the
other to ensure that all prior art that is pertinent to the examination of a
patent or application relating to a Joint Invention or an invention covered by
Section 8.3(d) hereof is brought to the attention of the other party. The
parties to this Agreement shall have the right to review and comment on
substantive documents prepared in connection with the preparation, filing,
prosecution and maintenance of patents and applications relating to a Joint
Invention or an invention covered by Section 8.3(d) hereof prior to the filing
of such papers; however, such review and comment shall be performed
expeditiously so as not to negatively affect patent rights.

        9.5 PROJECT PATENTS; LICENSING PAYMENTS TO THIRD PARTIES.

               (a) The Management Board will conduct a periodic review (at least
annually), in consultation with the Patent Committee, to identify those Baxter
Patents and Cerus Patents that are protective of the Systems under development,
or developed, pursuant to this Agreement. Any such Baxter Patents or Cerus
Patents that are so identified (other than patents or patent applications that
are primarily directed toward applications outside the Field, and only
incidentally directed toward the Field) shall be designated Project Patents. In
such periodic 


                                      35.


<PAGE>   42
reviews, the Management Board may also determine that certain Baxter Patents or
Cerus Patents that were previously designated as Project Patents will be removed
from such designation.

               (b) In the event that the Management Board determines that a
license from a third party is necessary or desirable in connection with the sale
of any System developed under this Agreement, the parties will share the cost of
obtaining and maintaining such license. If a Patent Fee Payment is required to
obtain or maintain such license, the party negotiating the license will make
such payment, and the other party will reimburse the paying party for fifty
percent (50%) of the amount of such payment within sixty (60) days after such
payment is made. Patent Royalty Payments on Project Patents, and Patent Royalty
Payments approved by the Management Board for patents that are not designated as
Project Patents, will be paid by Baxter (if Baxter is the selling party) or
Cerus (if Cerus is the selling party) for any System and deducted in computing
the Premium arising from sales by such party. Notwithstanding the foregoing,
with respect to any patents obtained to support the S59 FFP System, Cerus will
solely pay any Patent Fee Payment (to the extent such Patent Fee Payment is
allocable to S59 FFP, but not to the extent it is allocable to other systems
being developed under this Agreement or the Platelet Agreement) and will also
pay Patent Royalty Payments, and charge such Patent Fee Payments and Patent
Royalty Payments as Cost of Goods in Computing Premium. 

        9.6 PATENT EXPENSES. The reasonable expenses, incurred on or after
January 1, 1997 of preparing, filing, prosecuting and maintaining Project
Patents and Joint Patents in the countries of the United States, Australia,
Canada, the United Kingdom, Germany, Belgium, France, Italy, Netherlands, and
Japan, and all other countries that are agreeable to Baxter and Cerus, as
evidenced in writing shall be borne equally. The parties shall reconcile on a
semi-annual basis on or about the last business day of each February and August,
commencing August, 1998, all such expenses incurred by the respective parties
during the previous semi-annual period (or previous semi-annual periods that
have not yet been reconciled). In such reconciliation, Baxter will make a cash
payment to Cerus, or Cerus will make a cash payment to Baxter, so that such
expenses are borne equally by the parties. Unless countries other than those
expressly listed above are agreed to by the parties in writing, such other
country filings shall not be made. Except as set forth above in this Section
with respect to Project Patents, Cerus will bear the expenses of preparing,
filing, prosecuting and maintaining Cerus Patents, and Baxter will bear the
expense of preparing, filing, prosecuting and maintaining Baxter Patents.

        9.7 ELECTION NOT TO PAY EXPENSES. If either party does not for any
reason pay its share of the reasonable expenses for a particular Project Patent
or Joint Patent, then, at the option of the other party:

               (a) the interest of that nonpaying party with respect to that
particular patent application or patent shall immediately terminate and the
paying party shall be assigned and exclusively own that particular patent or
patent application, without affecting the nonpaying party's rights under all
other patent applications and patents; or

               (b) the application or patent shall be allowed to lapse.

        In the event the paying party elects option (a) above, the nonpaying
party hereby agrees to execute documents necessary to transfer its interest in
such patent or patent application to the paying party.


                                      36.


<PAGE>   43
10.     TRADEMARKS.

        10.1 BAXTER TRADEMARKS. Cerus shall make no use of any Baxter trademark
without the prior written approval by Baxter.

        10.2 CERUS TRADEMARKS. Baxter shall include the Cerus name and mark (or
successor name and mark) in a prominent manner on packaging, literature and
promotional material and advertising for the System unless Baxter makes a good
faith determination that the Cerus name cannot be used due to third party
rights. Baxter shall, to the extent practical, provide to Cerus for review
copies of all proposed uses of the Cerus name and mark and references to Cerus.
At Cerus' reasonable request, Baxter shall refer to the Cerus Compounds by the
Cerus trademark that Cerus indicates is appropriate. Baxter shall include on
material bearing such trademarks an acknowledgment that such trademarks are the
property of Cerus. If necessary in any market to maintain Cerus' rights in the
Cerus trademarks, Baxter shall enter into a registered user agreement regulating
its use of the Cerus trademarks. Except as provided in this Section, no rights
to Cerus trademarks are hereby granted to Baxter.

11.     CONFIDENTIAL INFORMATION.

        11.1 CONFIDENTIALITY AGREEMENT. The use and disclosure of information
designated by either party as confidential shall be governed by the attached
Schedule E Confidentiality Agreement. The Schedule E Confidentiality Agreement
shall survive termination of this Agreement.

        11.2 USE OF CONSULTANTS. The parties contemplate that from time to time
during the term of this Agreement third party technical consultants may be
employed by either party in connection with the development of Cerus Compounds,
Baxter Compounds, New Technology Compounds or Systems. The parties agree that
information designated as confidential may be disclosed to such consultants
provided that the other party is given reasonable notice of the circumstances
and nature of the intended disclosure and that the disclosure is limited to
information necessary to enable the technical consultant to provide technical
consulting services. The consultant will be required to sign an agreement
committing the consultant to protect such confidential information.

12.     CESSATION OF COOPERATIVE DEVELOPMENT WORK.

        12.1 CESSATION. Either party may unilaterally cease all participation in
the Cooperative Development Work on a specific approved Project or all
Cooperative Development Work under this Agreement upon two hundred seventy (270)
days' written notice of its intent. During such 270-day period, the party
unilaterally ceasing participation shall continue to perform the tasks
previously agreed on and shall continue to support such party's share of (a) the
approved budget for such 270-day period, as provided in Section 3 of this
Agreement, or (b) if the budget has not yet been approved for such full 270-day
period, the budgeted amount for that period for which there is an approved
budget plus for each month during such 270-day period for which there is not an
approved budget, an amount equal to the average monthly budget for the last
three months for which there was an approved budget. any time thereafter, the
party who did not unilaterally cease participation in the Cooperative
Development Work shall have the right to proceed with the independent
development of such System at its own expense. Should a party so proceed, the
following terms and conditions shall apply:


                                      37.


<PAGE>   44
               (a) The Premium Sharing Formula in Section 7.1 will be adjusted.
The Premium shall be split between the Parties based on the percentage of the
sum of (i) Final Project Total Budget funded by each Party, plus (ii) Noncash
Contributions to the Project made by each party, adjusted as provided in clauses
(b) and (c) below. Such percentage being calculated as follows: for purposes of
this Section only, after the cessation of funding by one Party, the funds
provided by the other Party thereafter to support the Cooperative Development
Work shall be considered doubled when calculating the Final Project Total Budget
and the corresponding respective percentage funded by each Party. All funds
provided by either Party pursuant to the approved Project Budget, or pursuant to
clause (b) in the first paragraph of Section 12.1 above, prior to a Party's
cessation shall be credited but not doubled.

               (b) In the event that Cerus unilaterally ceases all
participation, then at Baxter's election by written notice, all marketing rights
and licenses of Cerus hereunder to the System(s) developed or being developed
under such Project, or under the Development Work, as the case may be, shall
terminate, and Baxter shall source the Cerus Compounds from an alternative
source with the cooperation of Cerus, and the Revenue Sharing Formula in Section
7.1 will be adjusted under Sections 7.2 and 12.1(a); in addition, Baxter (but
not Cerus) shall be released from the obligations of Sections 3.8 and 6.3 with
respect to that part of the Field that such System is intended to address.

               (c) In the event that Baxter unilaterally ceases all
participation, then at Cerus' election by written notice, all marketing rights
and licenses of Baxter to the System(s) developed or being developed under such
Project, or under the Cooperative Development Work, as the case may be, shall
terminate and Cerus shall have exclusive rights to market, sell and distribute
such System throughout the world. Baxter shall provide the necessary Baxter
disposables, apheresis kits, Blood Pack Units(R), Instruments, Baxter Compounds,
New Technology Compounds that the Management Board determines shall be supplied
by Baxter, or other components necessary for Cerus, or Cerus' Approved
Distributor to sell Systems under Section 6.7. Revenue Sharing under Section 7.1
shall be adjusted under Sections 7.3, 7.4 and 12.1(a); in addition, Cerus (but
not Baxter) shall be released from the obligations of Sections 3.8 and 6.3 with
respect to that part of the Field that such System is intended to address.

        12.2 CESSATION PAYMENT. In the event that either party gives notice of
unilateral cessation of participation on a specific approved Project or all
Cooperative Development Work under this Agreement, such party shall, not later
than twenty (20) days after the date of such notice, pay to the other party an
amount equal to [...***...] period following the date of such cessation, or (b)
if the budget has not yet been approved for such full [...***...] period, the
[...***...]. Such cessation payment need not be applied by the receiving party
to continuation of work on such Project or Cooperative Development Work. Neither
party shall be entitled to give notice of unilateral cessation of participation
on the Red Cell Project prior to January 1, 1999 on any other Project prior to
two years after the approval of the Management Board to commence the Project,
provided, however, that either party shall have the right to give notice of
unilateral cessation of a Project prior to that date if such party concludes,
reasonably and in good faith, based on an unambiguous, unsuccessful outcome in a
critical test in the Project test protocol that there is no reasonable
likelihood that the Project will attain Regulatory Approval.

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      38.


<PAGE>   45
        12.3 SECTION 12 NOT APPLICABLE TO S59 FFP. Notwithstanding the preceding
provisions of Section 12, neither Section 12.1 nor 12.2 shall apply to the S59
FFP Project. Cerus may, at any time, cease to pursue the S59 FFP Project, and
neither party will have any obligation under Section 12.2 to the other with
respect to the S59 FFP Project.

13.     REPORTS.

        13.1 QUARTERLY SALES REPORTS. Each quarterly payment made under Section
7 shall be accompanied by a full and accurate accounting of all Net Sales of
Systems by Baxter and Cerus, as the case may be, for the calendar quarter. Each
such report shall include at least the following information for each type of
System separately as to each of the following regions: U.S., Europe, Japan, rest
of world:

               (a) The number of stand-alone Inactivation Packages and
Integrated Inactivation Sets sold to third parties by Baxter or Cerus, as the
case may be;

               (b) The Net Sales, with a breakdown between Net Sales of
stand-alone Inactivation Packages and Integrated Inactivations Sets;

               (c) Cost of Goods/Base Revenue with a breakdown between
stand-alone Inactivation Packages and Integrated Inactivation Sets;

               (d) Computation of the Revenue Sharing Payment due to the other
party.

               (e) Customer published price lists for Systems; and

               (f) Any deductions from Revenue Sharing Payments.

Each report shall include the certification of the party making the report
attesting to the fact that the report is an accurate and complete accounting of
all information required hereunder.

To the extent Baxter is unable to provide any such information when due, Baxter
will provide to Cerus at such time Baxter's best estimates of such information,
and will provide actual information as soon as it is available, provided,
however, that Baxter will, in any event, provide reports when due of actual Net
Sales and Cost of Goods/Base Revenue.

        13.2 COST OF GOODS/BASE REVENUE. To the extent not provided under
Section 13.1 above, each party will furnish quarterly reports to the other party
on such party's Cost of Goods/Base Revenue for components supplied by such
party.

14.     BOOKS AND RECORDS.

        14.1 RECORDS. Baxter and Cerus shall keep full and accurate books of
account containing all particulars that may be necessary for the purpose of
calculating all amounts owing to either party. Books of account maintained by
the parties shall be kept at their principal place of business. All such reports
and data shall be open for inspection on a confidential basis at all reasonable
times and either party may conduct at its own expense, once every year during
normal business hours through an independent certified public accountant, an
examination of the accounts contemplated above. If any audit shall show that the
selling party underpaid amounts 


                                      39.


<PAGE>   46
due under this Agreement herein as to the period subject of the audit, then the
party which underpaid shall immediately pay to the other any such deficiency
with interest thereon in accordance with Section 14.3. If the underpayment shall
exceed ten percent (10%) of the amount owed for any calendar year, the party
underpaying shall also reimburse the other for costs related to such audit.

        14.2 RETENTION. Books and records required to be maintained by the
parties hereunder shall be retained for at least two (2) years from the date of
the payment to which they pertain.

        14.3 INTEREST. All payments due hereunder that are not paid when due and
payable hereunder shall bear interest at an annual rate equal to 4% (four
percent) above the U.S. dollar reference rate ("prime rate") charged from time
to time by Bank of America N.T. & S.A., or any successor thereto, from the date
due until paid or at such lower rate as shall be the maximum rate permitted by
law.

15.     TERM.

        This Agreement shall continue so long as any System is being developed
or marketed under this Agreement, unless terminated earlier pursuant to Section
16.1, and provided that Cooperative Development Work may be earlier terminated
pursuant to Section 12.1. Further, upon expiration of the agreement, except as
otherwise provided herein, no Party shall be obligated to provide materials,
disposables, Blood Pack Units(R), apheresis kits, delivery systems, Instruments
and chemicals to the other Party. Upon termination of any Project by the
Management Board or by mutual consent, all licenses hereunder (except those
licenses granted pursuant to Section 8.6) shall terminate with respect to the
subject matter of such Project (which shall not affect licenses with respect to
any other Project). In the event that either party hereunder ceases
participation, in the Cooperative Development Work for the Red Blood Cell
Project, other than pursuant to the proviso in the last sentence of Section
12.2, all licenses of such party under this Agreement shall terminate except
such licenses as may be necessary or useful in connection with other then
ongoing approved Projects. Any license under Sections 8.5 and 8.6 hereof,
however, shall survive any termination of this Agreement.

16.     BREACH.

        16.1 MATERIAL BREACH. Either party may terminate this Agreement for any
material breach by the other party sixty (60) days after providing the other
party with written details of the breach if the breach remains uncured at the
end of the sixty (60) day notice period. Notwithstanding the preceding sentence,
each party acknowledges that the ability of the other party to carry on the
Cooperative Development work will be substantially adversely affected in the
event that such party does not make payment when due to the other party.
Accordingly, in the event of the failure to make any payments that are due and
owing, or fund any equity purchase, a thirty (30) day notice period shall apply
in lieu of such sixty (60) day notice period in the preceding sentence.

        16.2 RIGHTS ON TERMINATION. In the event of termination by either party
as provided in Section 16.1, without limiting any other rights or remedies, such
party shall have the rights provided for under Section 12 of the Agreement as if
the other party had unilaterally ceased participation in the Cooperative
Development Work.


                                      40.


<PAGE>   47
17.     REPRESENTATIONS AND INDEMNITIES.

        17.1 CERUS REPRESENTATIONS. Cerus represents and warrants to Baxter as
of the Effective Date that:

               (a) It has granted no prior license or assignment of rights under
the Cerus Patents in the Field.

               (b) There are no foreign or United States administrative,
judicial or Patent and Trademark Office proceedings contesting the inventorship
or ownership of any Cerus Patent;

               (c) Neither the execution and delivery of this Agreement, nor the
performance of the obligations of Cerus hereunder shall result in a violation,
breach or event of default (or any event or condition which with notice or the
passage of time or both would constitute an event of default) of or with respect
to any agreement, mortgage, indenture or order of any court of competent
jurisdiction binding upon Cerus or upon the property of Cerus;

               (d) It is party to no contract materially adverse to the
obligations undertaken and rights granted in this Agreement;

               (e) The execution of this Agreement and delivery to Baxter does
not conflict with the terms of any agreement to which Cerus is bound.

               (f) The Technology Transfer Agreement and the License Agreement
between Cerus and HRI Research, Inc. each dated December 13, 1991 are in full
force and effect and are binding and enforceable in accordance with their terms.

               (g) That Cerus has advised Baxter of any knowledge of any third
party patent or Know-How that might be infringed by the incorporation of any
Cerus Patent or Cerus Know-How likely to be embodied or used in a System; and

               (h) Cerus has advised Baxter of any technology not licensed to
Baxter hereunder, that it believes would be necessary to optimally use the Cerus
Compound in a System.

        17.2 CERUS INDEMNIFICATION -- REPRESENTATIONS AND WARRANTIES. Cerus
shall indemnify Baxter for any losses sustained or expenses incurred by Baxter
as a result of a breach by Cerus of any of the foregoing representations and
warranties.

        17.3 CERUS INDEMNIFICATION -- PRODUCTS. Cerus shall indemnify, hold
harmless and defend Baxter from and against any and all claims, damages,
liability, suits, actions and expenses, including reasonable attorney's fees, by
reason of liability imposed by law upon Baxter resulting from the sale of
Systems to the extent any such liability, expressly including, but not limited
to products liability, arises from the failure to conform to specifications for
Cerus Compounds incorporated into Systems; provided that Baxter shall give Cerus
prompt written notice of such claim and Cerus shall have the right to defend
such claim (Baxter having the right to participate in any such defense at
Baxter's own expense).


                                      41.


<PAGE>   48
        17.4 INSURANCE. Cerus shall, at its own expense, establish and at all
times during the period from Market Launch until three (3) years after the last
delivery of a System under this Agreement products liability insurance in an
amount not less than $5,000,000 each occurrence combined single limit bodily
injury and property damage, provided that such insurance is available on
commercially reasonable terms. The insurance policy shall be endorsed to name
Baxter as an additional insured and to provide for written notification to
Baxter by the insurer not less than thirty (30) days prior to cancellation,
non-renewal or material change. A certificate of insurance evidencing compliance
with this section and referencing this Agreement shall be furnished to Baxter by
Cerus within ten (10) days of Market Launch.

        17.5 BAXTER REPRESENTATIONS. Baxter represents and warrants to Cerus as
of the Effective Date that:

               (a) It has granted no prior license or assignment of rights under
the Baxter Patents that would materially impair its ability to develop,
manufacture or sell Systems.

               (b) There are no foreign or United States administrative,
judicial or Patent and Trademark Office proceedings contesting the inventorship
or ownership of any Baxter Patent that is likely to be embodied or used in a
System.

               (c) neither the execution and deliver of this Agreement, nor the
performance of the obligations of Baxter hereunder shall result in a violation,
breach or event of default (or any event or condition which with notice or the
passage of time or both would constitute an event of default) of or with respect
to any agreement, mortgage, indenture, or order of any court of competent
jurisdiction binding upon Baxter or upon the property of Baxter.

               (d) it is party to no contract materially adverse to the
obligations undertaken in this Agreement.

               (e) The execution of this Agreement and delivery to Cerus does
not conflict with the terms of any agreement to which Baxter is bound.

               (f) Except as previously disclosed to Cerus, Baxter has no
current agreements with other parties for the development and commercialization
of systems for the inactivation of pathogens in the Approved Project Field.

               (g) Baxter has advised Cerus of any knowledge of any third party
patent or know-how that might be infringed by the incorporation by Baxter of any
Baxter Patent or Baxter Know-How likely to be embodied or used in a System.

               (h) Baxter has advised Cerus of any technology not licensed to
Baxter it believes would be necessary to optimally use the Baxter Patents or
Baxter Know-How in a System.

        17.6 BAXTER INDEMNIFICATION - REPRESENTATIONS AND WARRANTIES. Baxter
shall indemnify Cerus for losses sustained or expenses incurred by Cerus as a
result of a breach by Baxter of the foregoing representations and warranties.


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<PAGE>   49
        17.7 BAXTER INDEMNIFICATION - PRODUCTS. Baxter shall indemnify, hold
harmless and defend Cerus from and against any and all claims, damages,
liability, suits, actions and expenses, including reasonable attorney's fees, by
reason of liability imposed by law upon Cerus resulting from the sale of Systems
to the extent any such liability, including but not limited to product
liability, arises from the failure of components of Systems supplied by Baxter,
excluding Instruments if manufactured by a third party (provided that Baxter
shall contractually require any third-party manufacturer to indemnify Cerus to
the full extent that Baxter is indemnified by such manufacturer), to conform to
specifications; provided that Cerus shall give Baxter prompt written notice of
such claim and Baxter shall have the right to defend such claim (Cerus having
the right to participate in such defense at its own expense).

        17.8 BAXTER INSURANCE. In the event that the net worth of Baxter shall
at any time be reduced to less than $2 billion U.S., Baxter shall, at its own
expense, establish and at all times that such net worth is not maintained until
three (3) years after the last delivery of a System under this Agreement
maintain products liability insurance in an amount not less than $5,000,000 each
occurrence combined single limit bodily injury and property damage, provided
that such insurance is available on commercially reasonable terms. The insurance
policy shall be endorsed to name Cerus as an additional insured and to provide
for written notification to Cerus by the insurer not less than thirty (30) days
prior to cancellation, non-renewal or material change. A certificate of
insurance evidencing compliance with this section and referencing this Agreement
shall be furnished to Cerus by Baxter within ten (10) days of the date that
Baxter becomes obligated to establish such insurance.

18.     INFRINGEMENT.

        18.1 DEFENSE OF THIRD PARTY INFRINGEMENT SUITS. In the event that a
third party shall sue either party alleging that the manufacture, use or sale of
a System, or any part thereof, infringes a patent of such third party, then the
Management Board shall have the option to control the defense of such suit. The
parties shall provide reasonable cooperation in the defense of such suit and
furnish all evidence in their control. All attorneys' fees as well as any
judgments, settlements, or damages payable with respect to such suit shall be
subject to cost sharing pursuant to Section 3.5 and shall be added to the Final
Project Total Budget. Neither party shall enter into any settlement that
materially affects the other party's rights or interests without such other
party's prior written consent, which consent shall not be unreasonably withheld.

        18.2 SUITS FOR INFRINGEMENT BY OTHERS. In the event Baxter or Cerus
becomes aware of any actual or threatened infringement of the Cerus Patents or
the Cerus Know-How licensed hereunder, or the Baxter Patents or Baxter Know-How
licensed hereunder, that party shall promptly notify the Management Board and
the Management Board shall determine the most appropriate action to take. All
expenses for pursuing such suit shall be subject to cost sharing. Any award in
such suit shall be divided between the parties in proportion to the parties'
relative combined cash contributions and Noncash Contributions to the product or
process that is subject to the infringement.


                                      43.


<PAGE>   50
        In the event the accused product is not in competition with a System in
the Field,

               (a) Cerus alone may, in its sole discretion and at its expense,
initiate and conduct an infringement action relating to alleged infringement of
Cerus Patents or Cerus Know-How and keep any settlement or award which may be
obtained.

               (b) Baxter alone may, in its sole discretion and at its expense,
initiate and conduct an infringement action relating to alleged infringement of
Baxter Patents or Baxter Know-How and keep any settlement or award which may be
obtained.

19.     PREFERRED STOCK PURCHASE.

        Baxter will, upon Cerus' written request, purchase such amount of
Preferred Stock as Cerus shall request having an aggregate purchase price not
exceeding nine million five hundred thousand dollars ($9,500,000). The terms of
such Special Preferred Stock are set forth in a Series B Preferred Stock
Purchase Agreement being executed by the parties concurrently herewith.

20.     GENERAL.

        20.1 ENTIRE AGREEMENT. (1) This Agreement and Schedules, (2) the
attached Schedule E Confidentiality Agreement of even date, (3) each stock
purchase agreement pursuant to Section 4.1 hereof, and (4) the Plasma
Derivatives Letter contain the entire agreement between the parties relating to
the subject matter hereof and all prior understandings, representations and
warranties between the parties are superseded; provided, however, that this
Agreement does not limit any agreement restricting disclosure or use of
confidential or proprietary information previously entered into between the
parties. None of the terms of this Agreement shall be deemed to be waived or
amended by either party unless such a waiver or amendment specifically
references this Agreement and is in writing signed by the party to be bound.
Nothing in this Agreement is intended to amend or modify the Platelet Agreement,
except that this Agreement supersedes Sections 8.7 and 8.8 of such agreement,
which provisions shall cease to be effective upon the execution and delivery of
this Agreement.

        20.2 RELATIONSHIP OF PARTIES. Baxter acknowledges that it is not an
agent of Cerus and has no authority to speak for, represent, or obligate Cerus
in any way. Cerus acknowledges that it is not an agent of Baxter and has no
authority to speak for, represent, or obligate Baxter in any way. This Agreement
does not and shall not be deemed to create any relationship of a joint venture
or a partnership.

        20.3 SENIOR BAXTER CONTACT. The senior Baxter contact of the purpose of
administering this Agreement is President, Fenwal, One Baxter Parkway,
Deerfield, Illinois 60015. At present, Roberto Perez occupies this position.

        20.4 SENIOR CERUS CONTACT. The senior Cerus contact for the purpose of
administering this Agreement is the President of Cerus at the address first
above written. At present, Mr. Stephen T. Isaacs occupies this position.

        20.5 SEVERABILITY. The parties do not intend to violate any public
policy or statutory or common law. However, if any sentence, paragraph, clause
or combination of this Agreement is 


                                      44.


<PAGE>   51
in violation of any law or is found to be otherwise unenforceable by a court
from which there is no appeal, or no appeal is taken, such sentence, paragraph,
clause, or combination of the same shall be deleted and the remainder of this
Agreement shall remain binding, provided that such deletion does not alter the
basic structure of this Agreement. In such event, the parties shall renegotiate
this Agreement in good faith, but should such negotiations not result in a new
agreement with ninety (90) days of the initiation of such negotiations, then
this Agreement may be terminated by either party by thirty (30) days notice to
the other.

        20.6 FORCE MAJEURE. Any party shall be excused from the performance of
its obligations under this Agreement and shall not be liable for damages to the
other if such performance is prevented by circumstances beyond its effective
control. Such excuse from performance shall continue so long as the condition
responsible for such excuse continues and for a thirty (30) day period
thereafter. For the purposes of this Agreement, circumstances beyond the control
of a party which excuse that party from performance shall include, but shall not
be limited to, acts of God, acts, regulations or laws of any government
including currency controls, war, civil commotion, commandeer, destruction of
facility or materials by fire, earthquake, storm or other casualty, labor
disturbances, judgment or injunction of any court, epidemic, and failure of
public utilities or common carrier.

        20.7 NOTICES. All notices and demands required or permitted to be given
or made pursuant to this Agreement shall be in writing and shall be effective
when personally given or made or when placed in an envelope and deposited in the
United States mail postage prepaid, addressed as follows:

IF TO BAXTER:                           IF TO CERUS, IN CARE OF:

General Counsel                         President and Chief Executive Officer
Baxter Healthcare Corporation           Cerus Corporation
One Baxter Parkway                      2525 Stanwell Drive, Suite 300
Deerfield, Illinois  60015              Concord, California  94520

WITH A COPY TO:                         WITH A COPY TO:

President, Fenwal Division              Howard G. Ervin
Baxter Healthcare Corporation           Cooley Godward LLP
One Baxter Parkway                      One Maritime Plaza, 20th Floor
Deerfield, Illinois  60015              San Francisco, California  94111

or to such other address as to which either party may notify the other.

        20.8 BINDING. This Agreement shall be binding upon and inure to the
benefit of the parties, their successors and assigns. This Agreement shall be
assignable: (i) by either party without the consent of the other to any
Affiliate of the party (an Affiliate being defined as any entity in which the
party or its parent owns or controls directly or indirectly, forty percent (40%)
or more of the voting securities); (ii) by either party with the written consent
of the other; (iii) by either party without the consent of the other in
connection with the purchase or other acquisition of substantially all the
assets of its business to which this Agreement relates; or (iv) by either party
in connection with a reincorporation under the laws of another state. Any
attempted assignment which does not comply with the terms of this Section shall
be void.


                                      45.


<PAGE>   52
        20.9 GOVERNING LAW. This Agreement is deemed to have been executed in
and shall be governed by and construed according to the laws of the State of
Illinois.

        20.10 VENUE. In the event that Baxter files suit against Cerus, it shall
do so in, and hereby agrees to submit to, the jurisdiction of a court in U.S.
District Court, N.D. California. In the event that Cerus files suit against
Baxter, it shall do so in, and hereby agrees to submit to, the jurisdiction of
the U.S. District Court, N.D. Illinois.

        20.11 DISBURSEMENTS. Unless otherwise agreed between the parties, all
disbursements from one party to another under this Agreement shall be paid on or
before the due date by wire transfer to the bank account specified in writing by
the party receiving the disbursement.

        20.12 PUBLICITY. Neither Baxter, Cerus, nor any of their respective
representatives shall issue or cause the publication of any press release,
announcement, or public communication with respect to this Agreement, the Series
A Preferred Stock Purchase Agreement dated the First Amendment Effective Date,
the Series B Preferred Stock Purchase Agreement or the Memorandum of Agreement
between Baxter and Cerus of even date herewith, or the transactions contemplated
hereby or thereby, without the prior written consent of the other party, which
consent will not be unreasonably withheld or delayed. Cerus, however, will not
be restricted from making any public disclosure or filing with a regulatory
agency, if its counsel advises Cerus that such disclosure or filing is required
or advisable to comply with applicable legal requirements.

        20.13 SURVIVAL. Sections 3.1(e)(ii), 8.5, 8.6, 11.1, 16.2, 17.3 and
17.7, and Section 1 to the extent it defines terms in such sections, shall
survive the termination of this Agreement. Any payment obligations accruing
prior to termination shall survive termination until paid, and Section 14 hereof
shall survive termination for a period of two years.


                                      46.


<PAGE>   53
        IN WITNESS WHEREOF, this Agreement is signed by duly authorized
representatives of each party as of the Effective Date.

BAXTER HEALTHCARE CORPORATION                  CERUS CORPORATION




By:     /s/ Roberto Perez                      By:      /s/ Stephen T. Isaacs
        -------------------------------                -----------------------
        Roberto Perez                                  Stephen T. Isaacs
Title:  President, Fenwal Division             Title:  President


<PAGE>   54
                                  SCHEDULE A-1

                             INITIAL RED CELL BUDGET


<PAGE>   55
                                RED CELL PROGRAM

                                 REVISED BUDGET

                                FEBRUARY 28, 1996


<TABLE>
<CAPTION>
STERITECH            1996                 1997                 1998                 1999            
              -----------------    -----------------    ------------------    ------------------    
R & D                                                                                               
                FTE        $         FTE        $         FTE         $         FTE         $       
              -------   -------    -------   -------    -------    -------    -------    -------    
<S>           <C>       <C>        <C>       <C>        <C>        <C>        <C>        <C>        
Personnel     [.***.]   [.***.]    [.***.]   [.***.]    [.***.]    [.***.]    [.***.]    [.***.]    
Out of Pocket           [.***.]              [.***.]               [.***.]               [.***.]    
Instrument              [.***.]              [.***.]               [.***.]               [.***.]    
                                                                                                    
Baxter R & D                                                                                        
                                                                                                    
Personnel     [.***.]   [.***.]    [.***.]   [.***.]    [.***.]    [.***.]    [.***.]    [.***.]    
Out of Pocket           [.***.]              [.***.]               [.***.]               [.***.]    
Instrument              [.***.]              [.***.]               [.***.]               [.***.]    
                                                                                                    
Outside                                                                                             

[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]    
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]    
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]    
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]    
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]    

Total                   [.***.]              [.***.]               [.***.]               [.***.]    
</TABLE>

<TABLE>
<CAPTION>
STERITECH           2000                 2001
              -----------------   -----------------   Project
R & D                                                  Total
                FTE        $        FTE        $
              ------    -------   ------    -------   -------
<S>           <C>       <C>       <C>       <C>        <C>
Personnel     [.***.]   [.***.]   [.***.]   [.***.]    [.***.] 
Out of Pocket           [.***.]             [.***.]    [.***.] 
Instrument              [.***.]             [.***.]    [.***.] 
                                                     
Baxter R & D                                         
                                                     
Personnel     [.***.]   [.***.]   [.***.]   [.***.]    [.***.] 
Out of Pocket           [.***.]             [.***.]    [.***.] 
Instrument              [.***.]             [.***.]    [.***.] 
                                                     
Outside                                              

[.***.]                 [.***.]             [.***.]    [.***.]  
[.***.]                 [.***.]             [.***.]    [.***.]  
[.***.]                 [.***.]             [.***.]    [.***.]  
[.***.]                 [.***.]             [.***.]    [.***.]  
[.***.]                 [.***.]             [.***.]    [.***.]  

Total                   [.***.]             [.***.]    [.***.]  
</TABLE>                           


                 RED CELL BUDGET, 1996 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category                  Explanation                   FTE/$
- --------                  -----------                   -----
<S>                       <C>                         <C>
Out of Pocket              [.***.]                    $[.***.] 
[.***.]                    [.***.]                     [.***.] 
Instrument                 [.***.]                    $[.***.] 
[.***.]                    [.***.]                     [.***.] 
[.***.]                    [.***.]                     [.***.] 
[.***.]                    [.***.]                     [.***.] 
[.***.]                    [.***.]                     [.***.] 
Project Leader             [.***.]                     [.***.] 
                                                       [.***.] 
Total                                                 $[.***.] 
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -1-


<PAGE>   56
                  RED CELL BUDGET, 1996 PROJECTION: BAXTER R&D

<TABLE>
<CAPTION>
Category              Explanation                           FTE/$
- --------              -----------                           -----
<S>                   <C>                                   <C>
Out of Pocket                                                   $[...***...]
Instrument            [...***...]                                [...***...]
[...***...]           [...***...]                                [...***...]
[...***...]           [...***...]                                [...***...]
Project Coordinator                                              [...***...]
                                                                 [...***...]
Total                                                           $[...***...]
</TABLE>


               RED CELL BUDGET, 1996 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
CATEGORY                 Explanation                                 $
- --------                 -----------                                ----------
<S>                      <C>                                       <C>
[...***...]              [...***...]                               [...***...]
[...***...]              [...***...]                               [...***...]
[...***...]              [...***...]                               [...***...]
                                                                   [...***...]
Total
</TABLE>


                 RED CELL BUDGET, 1997 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category                    Explanation                           FTE/$
- --------                    -----------                           -----
<S>                         <C>                                   <C>
Out of Pocket                                                         $[...***...]
[...***...]                 [...***...]                                [...***...]
[...***...]                 [...***...]                                [...***...]
[...***...]                 [...***...]                                [...***...]
[...***...]                 [...***...]                                [...***...]
[...***...]                 [...***...]                                [...***...]
[...***...]                 [...***...]                                [...***...]
Project Leader                                                         [...***...]
                                                                       [...***...]
Total                                                                 $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -2-


<PAGE>   57
                  RED CELL BUDGET, 1997 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation                 FTE/$
- --------              -----------                 -----
<S>                   <C>                         <C>
Out of Pocket                                          [...***...]
Instrument            [...***...]                      [...***...]
[...***...]           [...***...]                      [...***...]
[...***...]           [...***...]                      [...***...]
Instrument            [...***...]                      [...***...]
[...***...]           [...***...]                      [...***...]
Other Technical                                        [...***...]
Project Leader                                         [...***...]
                                                       [...***...]
Total                                                 $[...***...]
</TABLE>


               RED CELL BUDGET, 1997 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category              Explanation                     $
- --------              -----------                   -----------
<S>                   <C>                           <C>
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
Total                                               [...***...]
</TABLE>




                 RED CELL BUDGET, 1998 PROJECTION: STERITECH R&D

<TABLE>
<CAPTION>
CATEGORY              Explanation              FTE/$
- --------              -----------              -----
<S>                   <C>                      <C>
Out of Pocket                                       [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
[...***...]           [...***...]                   [...***...]
Project Leader                                      [...***...]
                                                    [...***...]
Total                                              $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -3-


<PAGE>   58
                  RED CELL BUDGET, 1998 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
CATEGORY          Explanation                      FTE/$
- --------          -----------                      -----
<S>               <C>                              <C>
Out of Pocket                                           [...***...]
Instrument        [...***...]                           [...***...]
[...***...]       [...***...]                           [...***...]
Instrument        [...***...]                           [...***...]
[...***...]       [...***...]                           [...***...]
Other Technical                                         [...***...]
Project Leader                                          [...***...]
                                                        [...***...]
Total                                                  $[...***...]
</TABLE>


               RED CELL BUDGET, 1998 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
CATEGORY              Explanation                              $
- --------              -----------                            -----------
<S>                   <C>                                    <C>
[...***...]           [...***...]                            [...***...]
[...***...]           [...***...]                            [...***...]
[...***...]           [...***...]                            [...***...]
[...***...]           [...***...]                            [...***...]
Total                                                        [...***...]
</TABLE>


                 RED CELL BUDGET, 1999 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category              Explanation                   FTE/$
- --------              -----------                   -----
<S>                   <C>                           <C>
Out of Pocket                                            [...***...]
[...***...]           [...***...]                        [...***...]
[...***...]           [...***...]                        [...***...]
[...***...]           [...***...]                        [...***...]
[...***...]           [...***...]                        [...***...]
[...***...]           [...***...]                        [...***...]
Project Leader                                           [...***...]
                                                         [...***...]
Total                                                   $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -4-


<PAGE>   59
                  RED CELL BUDGET, 1999 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
CATEGORY                     Explanation                   FTE/$
- --------                     -----------                   -----
<S>                          <C>                           <C>
Out of Pocket                                                   [...***...]
Instrument                   [...***...]                        [...***...]
[...***...]                  [...***...]                        [...***...]
[...***...]                  [...***...]                        [...***...]
Project Leader                                                  [...***...]
                                                                [...***...]
Total                                                          $[...***...]
</TABLE>



               RED CELL BUDGET, 1999 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category                    Explanation                          $
- --------                    -----------                    -----------
<S>                         <C>                            <C>
[...***...]                 [...***...]                    [...***...]
[...***...]                 [...***...]                    [...***...]
[...***...]                 [...***...]                    [...***...]
[...***...]                 [...***...]                    [...***...]
Total                                                      [...***...]
</TABLE>



                 RED CELL BUDGET, 2000 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket                                        [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader                                       [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>



                  RED CELL BUDGET, 2000 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation                 $
- --------              -----------               ----------
<S>                   <C>                       <C>
Out of Pocket                                   [...***...]
[...***...]           [...***...]               [...***...]
[...***...]           [...***...]               [...***...]
                                                [...***...]
Total                                           [...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -5-


<PAGE>   60
               RED CELL BUDGET, 2000 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Total                                               $[...***...]
</TABLE>




                  RED CELL BUDGET, 2000 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation                 $
- --------              -----------               -----------
<S>                   <C>                       <C>
Out of Pocket                                   [...***...]
Instrument            [...***...]               [...***...]
Technical support     [...***...]               [...***...]
Total                                           [...***...]
                                                [...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -6-


<PAGE>   61
                                  SCHEDULE A-2

                    1998 RED CELL PROGRAM BUDGET DEVELOPMENT

                                  [...***...]



- --------
* CONFIDENTIAL TREATMENT REQUESTED




<PAGE>   62
                                   SCHEDULE B

                             INITIAL S59 FFP BUDGET


<PAGE>   63
                                   FFP PROGRAM

                                 REVISED BUDGET

                                FEBRUARY 28, 1996

<TABLE>
<CAPTION>
STERITECH            1996                 1997                 1998                 1999                  2000       
              -----------------    -----------------    ------------------    ------------------    -----------------    Project
R & D                                                                                                                     Total
                FTE        $         FTE        $         FTE         $         FTE         $         FTE        $
              -------   -------    -------   -------    -------    -------    -------    -------    ------    -------    -------
<S>           <C>       <C>        <C>       <C>        <C>        <C>        <C>        <C>        <C>       <C>        <C>
Personnel     [.***.]   [.***.]    [.***.]   [.***.]    [.***.]    [.***.]    [.***.]    [.***.]    [.***.]   [.***.]    [.***.] 
Out of Pocket           [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.] 
                                                                                                                         [.***.] 

Baxter R & D

Personnel     [.***.]   [.***.]    [.***.]   [.***.]    [.***.]    [.***.]    [.***.]    [.***.]    [.***.]   [.***.]    [.***.] 
Out of Pocket           [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.] 
Instrument              [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.] 

Outside
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.]  
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.]  
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.]  
[.***.]                 [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.]  

Total                   [.***.]              [.***.]               [.***.]               [.***.]              [.***.]    [.***.]  
</TABLE>



                   FFP BUDGET, 1996 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category                                Explanation                 FTE/$
- --------                                -----------                 -----
<S>                                     <C>                        <C>
Out of Pocket                            [.***.]                   $[.***.] 
[.***.]                                  [.***.]                    [.***.] 
[.***.]                                  [.***.]                   $[.***.] 
[.***.]                                  [.***.]                    [.***.] 
[.***.]                                  [.***.]                    [.***.] 
[.***.]                                  [.***.]                    [.***.] 
[.***.]                                  [.***.]                    [.***.] 
                                                                   -------
Total                                                               [.***.] 
                                                                   $[.***.] 
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                       -1-


<PAGE>   64
                     FFP BUDGET, 1996 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>


                  FFP BUDGET, 1996 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
CATEGORY              Explanation                    $
- --------              -----------               -----------
<S>                   <C>                       <C>
[...***...]           [...***...]               [...***...]
[...***...]           [...***...]               [...***...]
Total                                           [...***...]
</TABLE>


                   FFP BUDGET, 1997 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -2-


<PAGE>   65


                     FFP BUDGET, 1997 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket                                        [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
                                                     [...***...]
Project Leader        [...***...]                    [...***...]
Total                                                [...***...]
                                                    $[...***...]
</TABLE>


                  FFP BUDGET, 1997 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category              Explanation                    $
- --------              -----------               -----------
<S>                   <C>                       <C>
[...***...]           [...***...]               [...***...]
[...***...]           [...***...]               [...***...]
[...***...]           [...***...]               [...***...]
Total                                           [...***...]
</TABLE>


                   FFP BUDGET, 1998 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
CATEGORY              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -3-


<PAGE>   66
                        FFP, 1998 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
CATEGORY              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
                                                     [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>


                  FFP BUDGET, 1998 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
CATEGORY              Explanation                    $
- --------              -----------               -----------
<S>                   <C>                       <C>
[...***...]           [...***...]               [...***...]
[...***...]           [...***...]               [...***...]
Total                                           [...***...]
</TABLE>


                   FFP BUDGET, 1999 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>


                     FFP BUDGET, 1999 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
CATEGORY              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
Total                                                [...***...]
                                                    $[...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -4-


<PAGE>   67
                  FFP BUDGET, 1999 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category              Explanation                    $
- --------              -----------               -----------
<S>                   <C>                       <C>
[...***...]           [...***...]               [...***...]
Total                                           [...***...]
</TABLE>


                   FFP BUDGET, 2000 PROJECTION: STERITECH R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
Out of Pocket         [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>


                        FFP, 2000 PROJECTION: BAXTER R&D


<TABLE>
<CAPTION>
Category              Explanation               FTE/$
- --------              -----------               -----
<S>                   <C>                       <C>
[...***...]           [...***...]                    [...***...]
[...***...]           [...***...]                    [...***...]
Project Leader        [...***...]                    [...***...]
                                                     [...***...]
Total                                               $[...***...]
</TABLE>


                  FFP BUDGET, 2000 PROJECTION: OUTSIDE EXPENSES


<TABLE>
<CAPTION>
Category              Explanation               [...***...]
- --------              -----------               -----------
<S>                   <C>                       <C>
[...***...]           [...***...]               [...***...]
Total                                           [...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


                                      -5-


<PAGE>   68
                                   SCHEDULE C

                                 NO SCHEDULE C


<PAGE>   69
                                   SCHEDULE D

                           PLASMA DERIVATIVES LETTER


<PAGE>   70
[BAXTER LETTERHEAD]

January 18, 1996

Mr. Stephen T. Isaacs
President and CEO
Steritech, Inc.
2525 Stanwell Drive
Suite 300
Concord, CA  94520

Re:       [...***...]

Dear Steve:

Thank you for your letter of December 26, 1995 discussing the rescission of your
Notice dated November 10, 1995. As we discussed on several occasions, Baxter is
[...***...]. It has always been the position of Baxter that the Steritech
decontamination technology would be [...***...]. With this in mind, this letter
confirms the agreement of Baxter and Steritech that:

        (i) Steritech is entitled to negotiate and enter into agreements with
third parties for the development and/or licensing to such third parties of
[...***...], free of any rights of Baxter and without obligation to Baxter,
except as set forth in clause (ii) below.

        (ii) In those cases where Steritech licenses [...***...] other than
Baxter, Steritech shall, at Baxter's written request, license such Steritech
technology to Baxter for such product on terms no less favorable than the terms
received by such other manufacturer.

Steritech will notify Baxter of the names of the their-party manufacturers with
whom Steritech is negotiating for licenses to Steritech's [...***...].

This letter agreement supersedes [...***...] of the Development, Manufacturing
and Marketing Agreement between Steritech and Baxter, dated as of December 10,
1993, insofar as such section concerns [...***...]. (For the purposes of this
letter, the term [...***...] used in such section.)


- --------
* CONFIDENTIAL TREATMENT REQUESTED



                                      -1-
<PAGE>   71
Upon the execution and delivery by Steritech of this letter where indicated
below, the Notice dated November 10, 1996 is rescinded.

Sincerely,



/s/  Kim C. Bush
Kim C. Bush
President, Fenwal Division
Biotech Group


AGREED AS SET FORTH ABOVE
Steritech, Inc.


By:  /s/ Stephen T. Isaacs
   -------------------------------
          Stephen T. Isaacs
          President


                                      -2-


<PAGE>   72
                                   SCHEDULE E

                            CONFIDENTIALITY AGREEMENT


<PAGE>   73
                            CONFIDENTIALITY AGREEMENT



        THIS AGREEMENT, made in March 18, 1996 with respect to the Development,
Manufacturing and Marketing Agreement ("Agreement") between Baxter and Steritech
dated as of April 1, 1996 between STERITECH, INC. ("Steritech"), having a
principal place of business as 2525 Stanwell Drive, Concord, California and
BAXTER HEALTHCARE CORPORATION ("Baxter"), a corporation having a principal place
of business at One Baxter Parkway, Deerfield, Illinois 60015, to assure the
protection and preservation of Proprietary Information disclosed or to be
disclosed or made available to each other in connection with the Agreement.

        WHEREAS, the parties have entered into a development, manufacturing and
marketing collaboration pursuant to the Agreement;

        WHEREAS, the parties desire to assure the confidential status of the
information which may be disclosed to each other in connection with the
Agreement;

        NOW THEREFORE, in reliance upon and in consideration of the following
undertakings, the parties agree as follows:

        1. All information disclosed to the other party shall be deemed to be
"Proprietary Information." In particular, Proprietary Information shall be
deemed to include any information, process, technique, algorithm, program,
design, drawing, formula or test data relating to any research project work in
progress, future development, engineering, manufacturing, marketing, servicing,
financing or personnel matter relating to the disclosing party, its present or
future products, sales, suppliers, clients, customers, employees, investors, or
business. Any Proprietary Information outside the scope of the Agreement shall
be identified by the disclosing party in writing and marked "Confidential" or if
such Proprietary Information is disclosed orally, within 30 days after such
disclosure the Proprietary Information shall be reduced to writing and marked
"Confidential" by the disclosing party and such writing forwarded to the
receiving party.

        2. The term "Proprietary Information" shall not be deemed to include
information which: (i) is now, or hereafter becomes, through no act or failure
to act on the part of the receiving party, generally known or available; (ii) is
known by the receiving party at the time of receiving such information as
evidenced by its records; (iii) is furnished to the receiving party by a third
party whom the receiving party believes has a right to disclose such
information; (iv) is independently developed by the receiving party without any
breach of this Confidentiality Agreement; and (v) is the subject of a written
permission to disclose provided by the disclosing party.

        3. Each party shall maintain in trust and confidence and not disclose to
any third party or use for any unauthorized purpose any Proprietary Information
received from the other party. However, each party may disclose Proprietary
Information to its affiliates who are bound by this Agreement (affiliates
include: any company owning 40% or more of a party, or a subsidiary of the
party, or a subsidiary of a party owning 40% or more of the party). Each party
may use such Proprietary Information only to the extent required under the
Agreement.


                                      -1-


<PAGE>   74
        4. The responsibilities of the parties with respect to the Proprietary
Information are limited to using the same degree of care used to protect their
own Proprietary Information from unauthorized use or disclosure. Both parties
shall advise their employees or agents who might have access to such Proprietary
Information of the confidential nature thereof.

        5. This Confidentiality Agreement shall continue in full force and
effect for so long as the parties continue to exchange Proprietary Information
under the Agreement. The termination of the Agreement shall not relieve either
party of the obligations imposed by this Confidentiality Agreement with respect
to Proprietary Information disclosed prior to the effective date of such
termination, which obligations shall survive the termination of the Agreement
for a period of two (2) years from the date of disclosure.

        6. Each party hereby acknowledges and agrees that in the event of any
breach of this Confidentiality Agreement by the other party, including, without
limitation, the actual or threatened disclosure of a disclosing party's
Proprietary Information without the prior express written consent of the
disclosing party, the disclosing party will suffer an irreparable injury, such
that no remedy at law will afford it adequate protection against, or appropriate
compensation for such injury. Accordingly, each party hereby agrees that the
other party shall be entitled to any injunctive relief as may be granted by a
court of competent jurisdiction.



AGREED TO:                                 AGREED TO:

STERITECH, INC.                            BAXTER HEALTHCARE CORPORATION





By:       Stephen T. Isaacs                By:       Kim Bush
          President                                  President, Fenwal Division


                                      -2-


<PAGE>   75
                                   SCHEDULE F

                                  NO SCHEDULE F


<PAGE>   76
                                   SCHEDULE G

                            STOCK PURCHASE AGREEMENT




<PAGE>   77
                                   SCHEDULE H

                     EXAMPLE OF COST OF GOODS/BASE REVENUE


                                  [...***...]


- --------
* CONFIDENTIAL TREATMENT REQUESTED


<PAGE>   78
                                   SCHEDULE I

                             AMORTIZATION SCHEDULE


<PAGE>   79
                                   SCHEDULE I

                       MAXIMUM AMOUNT OF AMORTIZATION TO
                            REDUCE COMMITTED FUNDING


        Set forth below are the maximum amounts of amortization that may reduce
the minimum committed funding by Baxter under Section 3.3.


<TABLE>
<CAPTION>
                                   MAXIMUM
        YEAR                      REDUCTION
        ----                      ---------
<S>                              <C>
        1998                     [...***...]
        1999                     [...***...]
        2000                     [...***...]
        2001                     [...***...]
        2002                     [...***...]
        2003                     [...***...]
</TABLE>

- --------
* CONFIDENTIAL TREATMENT REQUESTED


<PAGE>   80
                                   SCHEDULE J

                     BAXTER NON-EMPLOYEE SECURITY AGREEMENT


<PAGE>   81
                                   SCHEDULE J



BAXTER HEALTH CORPORATION                         NONEMPLOYEE SECURITY AGREEMENT
DEERFIELD, ILLINOIS  60015

IN CONSIDERATION OF MY POTENTIAL OR CONTINUED BUSINESS RELATIONSHIP OR
ASSOCIATION WITH BAXTER HEALTHCARE CORPORATION OR ONE OF ITS AFFILIATED
COMPANIES, SUCCESSORS OR ASSIGNS, (TOGETHER "BAXTER")

I, ________________________________ INDIVIDUALLY, AND ON BEHALF OF MY EMPLOYER,
          (PRINTED NAME)
_______________________________________________________________________FOR WHICH
               (PRINT COMPANY NAME AND ADDRESS)

I AM AUTHORIZED TO SIGN THIS AGREEMENT AGREE TO THE FOLLOWING TERMS AND
CONDITIONS OF ASSOCIATION:

        (a)     I UNDERSTAND THAT DURING THE COURSE OF MY ASSOCIATION WITH
                BAXTER I MAY ACQUIRE OR HAVE ACCESS TO INFORMATION THAT IS
                CONFIDENTIAL AND OF GREAT VALUE TO BAXTER. THIS INFORMATION MAY
                INCLUDE THE NATURE OF RESEARCH AND/OR DEVELOPMENT PROJECTS AS
                WELL AS DATA RELATING TO THEM; IT MAY FURTHER INCLUDE, WITHOUT
                LIMITATION, PRODUCTS, CUSTOMERS, SUPPLIERS, PRICING, COSTS,
                KNOW-HOW, STRATEGIES, PROGRAMS, PROCESSES, AND PRACTICES.

        (b)     I AGREE TO USE BAXTER'S CONFIDENTIAL INFORMATION ONLY FOR THE
                DIRECT AND SOLE BENEFIT OF BAXTER, AND I WILL NOT DISCLOSE
                BAXTER'S CONFIDENTIAL INFORMATION TO OTHERS WITHOUT THE EXPRESS
                WRITTEN AUTHORIZATION OF BAXTER, PROVIDED, HOWEVER, THAT ANY
                INFORMATION RELATING TO pathogen inactivation TECHNOLOGY OR
                PROGRAMS MAY BE DISCLOSED TO CERUS CORPORATION ("CERUS") FOR USE
                CONSISTENT WITH THE TERMS OF AGREEMENTS IN AFFECT BETWEEN BAXTER
                AND CERUS (THE "COLLABORATION AGREEMENTS").

        (c)     I AGREE THAT THE FOREGOING RESTRICTIONS ON THE USE AND
                DISCLOSURE OF BAXTER'S CONFIDENTIAL INFORMATION SHALL CONTINUE
                for ten years following the DATE OF THIS AGREEMENT AND SHALL
                SURVIVE TERMINATION OF MY ASSOCIATION WITH BAXTER. I UNDERSTAND
                FURTHER THAT THE FOREGOING RESTRICTIONS DO NOT APPLY TO
                INFORMATION WHICH I CAN ESTABLISH BY MY WRITTEN RECORDS WAS IN
                MY POSSESSION PRIOR TO DISCLOSURE BY BAXTER TO ME, OR IS OR
                BECOMES PUBLIC KNOWLEDGE THROUGH NO FAULT OF MY OWN, OR WHICH I
                ACQUIRE FROM OTHERS NOT UNDER OBLIGATION OF SECRECY TO BAXTER.

I UNDERSTAND THAT DURING THE COURSE OF MY ASSOCIATION WITH BAXTER I MAY ALSO
ACQUIRE OR HAVE ACCESS TO INFORMATION THAT IS CONFIDENTIAL AND OF GREAT VALUE TO
THIRD PARTIES. I WILL COMPLY WITH THE TERMS OF ANY APPLICABLE CONFIDENTIALITY
AGREEMENT BETWEEN BAXTER AND A THIRD PARTY, AND WILL NOT USE OR DISCLOSE THIRD
PARTY CONFIDENTIAL INFORMATION IN VIOLATION OF AN APPLICABLE CONFIDENTIALITY
AGREEMENT.

I WILL NOT REMOVE FROM BAXTER'S PREMISES ANY DOCUMENTS, FILES, RECORDS,
CORRESPONDENCE, NOTES, OR OTHER PAPERS (INCLUDING COPIES) RELATING TO THE
BUSINESS OF BAXTER, EXCEPT AS OUR ASSOCIATION SHALL REQUIRE AND WITH PERMISSION
OF AN AUTHORIZED BAXTER REPRESENTATIVE, AND IN SUCH CASES I WILL PROMPTLY RETURN
SUCH ITEMS TO BAXTER UPON REQUEST OR UPON TERMINATION OF MY ASSOCIATION.

IF DURING MY ASSOCIATION WITH BAXTER I AM GIVEN, OR PREPARE OR PRODUCE, ANY
DRAWINGS, SAMPLES, PROTOTYPES, PRODUCTS OR EQUIPMENT ACCORDING TO BAXTER'S
SPECIFICATIONS, OR INCORPORATING ANY OF BAXTER'S IDEAS OR TECHNOLOGY, I AGREE
NOT TO SHOW OR DISPLAY TO ANY THIRD PARTY, NOR IN ANY MANNER PUBLICLY USE, OR
GIVE, DISTRIBUTE, TRANSFER OR SELL, TO ANY THIRD PARTY ANY OF THE AFORESAID
ITEMS WITHOUT FIRST OBTAINING THE EXPRESS WRITTEN PERMISSION OF BAXTER, EXCEPT
DISCLOSURE TO CERUS AND USE CONSISTENT WITH THE COLLABORATION AGREEMENT.

I UNDERSTAND THAT, EXCEPT FOR INFORMATION DISCLOSED PURSUANT TO THE
COLLABORATION AGREEMENTS, BAXTER IS NOT WILLING TO ACCEPT ON A CONFIDENTIAL
BASIS ANY INFORMATION, SUGGESTION OR IDEA BELONGING TO ME OR MY EMPLOYER. I
THEREFORE AGREE THAT IF I DO DISCLOSE SUCH INFORMATION, SUGGESTION OR IDEA TO
BAXTER, BAXTER SHALL HAVE NO LIABILITY TO ME OR MY EMPLOYER BECAUSE OF BAXTER'S
DISCLOSURE OR USE OF SUCH INFORMATION, SUGGESTION OR IDEA, EXCEPT LIABILITY FOR
INFRINGEMENT OF ANY VALID PATENT NOW OR HEREAFTER ISSUED THEREON.

DATED THIS _______ DAY OF _____________________

                   SIGNATURE:____________________________________________

                   TITLE:________________________________________________
ACCEPTED ON  _____________________

                   BAXTER HEALTHCARE CORPORATION

                   BY:___________________________________________________

                   TITLE:________________________________________________



<PAGE>   1
                                                                    Exhibit 99.1

BAXTER COMMITS TO $14.5 MILLION CERUS
FINANCING AND EARMARKS JOINT
DEVELOPMENT FUNDING

July 8, 1998 4:45 PM EDT

CONCORD, Calif., July 8/PRNewswire/ -- Cerus Corporation (Nasdaq: CERS)
announced today that Baxter Healthcare Corporation has committed to purchase up
to $14.5 million of Cerus preferred stock. In addition to this equity financing,
Baxter will provide a minimum of $60 million over the next several years to fund
cooperative development of pathogen inactivation systems for platelets and red
blood cells. The companies are collaborating on the development of pathogen
inactivation systems for platelets, plasma and red blood cells used for
transfusion.

These new commitments to Cerus are related to the modification of agreements
governing the companies' joint development of pathogen inactivation systems.
Under the amended agreements, Cerus will receive a larger share of profits for
platelet and plasma systems once the jointly developed products reach
commercialization, in exchange for funding an increased portion of development
expenses.

"This new equity investment and the commitment to future development funding
demonstrate Baxter's continuing commitment to the commercialization of our
pathogen inactivation technology," observed Stephen Isaacs, Chief Executive
Officer of Cerus. "While we will incur higher near-term expenses, we're excited
that the new agreement enables Cerus to share more fully in the financial
opportunity of pathogen inactivation."

"We are committed to providing our customers innovative technologies that
enhance the safety of blood transfusions," said Roberto Perez, President of
Baxter's Fenwal division. "Through these agreements, we have reaffirmed our role
as joint development, manufacturing and marketing partner with Cerus on all of
their pathogen inactivation systems."

Of the total $14.5 million commitment, Baxter has purchased $5 million of Series
A preferred stock. These shares are convertible into common stock upon
regulatory approval of Cerus' proprietary pathogen inactivation system for
platelets at a price equal to 120 percent of the market price at the time of
conversion. In addition, Cerus may, at its option, sell Baxter $9.5 million of
Series B preferred stock during the twelve-month period beginning October 1,
1998. Twelve months after issuance, the Series B preferred stock may be
converted, at Baxter's option, into common stock at the market price at the time
of issuance. Cerus has the right to redeem each preferred series prior to any
conversion. Proceeds will be used to fund development of pathogen inactivation
systems for platelets, plasma and red blood cells used for transfusion.

Under the terms of the amended platelet agreement, Cerus has increased its
revenue participation by purchasing an additional 5.3 percent of net revenues
from future sales of the platelet pathogen 


                                       1.


<PAGE>   2
inactivation system, bringing its total share to approximately 33.5 percent, for
which it will pay $8.3 million to Baxter in 1999. Separately, Cerus will
increase its 1998 development funding for the platelet pathogen inactivation
system in exchange for a future cash payment of an amount equal to the increased
development funding.

Cerus has also increased its share of operating profits derived from future
sales of plasma pathogen inactivation systems. Under the revised plasma
agreement, Cerus will now receive 75% of operating profit, up from 50%
previously, in exchange for funding the remaining development expenses for this
program through regulatory approval. In addition to continuing to participate in
product development, Baxter will manufacture, market, and distribute the systems
worldwide.

The Cerus pathogen inactivation system for platelets is in a Phase 2c patient
study in the United States. The company's pathogen inactivation system for
plasma intended for transfusion is currently in a U.S. Phase 2 clinical study in
healthy subjects. The company's pathogen inactivation systems for red blood
cells is currently in pre-clinical toxicology and tolerability studies.

Cerus Corporation is developing systems designed to enhance the safety of blood
transfusions by inactivating infectious pathogens in blood components
(platelets, plasma and red blood cells used for transfusion) and by inactivating
white blood cells, which are responsible for a variety of adverse transfusion
reactions. The company's platform technology, which prevents viral, bacterial
and cellular replication, has additional potential applications in the health
care field beyond pathogen inactivation in blood components.

Cerus Corporation is collaborating with the Fenwal Division of Baxter Healthcare
Corporation to develop, manufacture and market pathogen inactivation systems for
blood components used for transfusion. Baxter, a global medical products and
services company, focuses on critical therapies for life-threatening conditions.
Baxter is a leader in technologies related to blood and the circulatory system.
The Fenwal Division develops, manufactures and markets products and services for
the collection, separation, storage and transfusion of blood and its components.

This news release contains forward-looking statements that involve risks and
uncertainties. Actual results could differ materially from the above
forward-looking statements, particularly those regarding product approvals,
commercialization, revenues and profits, as a result of certain factors,
including the uncertainty of the timing and results of any trials, regulation by
the FDA, modifications of the agreements with Baxter, the uncertainty of market
acceptance of any products, competitive conditions, the uncertainty of future
financing and other factors discussed in the company's 1997 Annual Report on
Form 10-K. SOURCE Cerus Corporation

(C)PR Newswire.  All rights reserved.



                                       2.




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