<PAGE>
EXHIBIT 10.72
CURIS, INC.
2000 DIRECTOR STOCK OPTION PLAN
1. Purpose.
--------
The purpose of this 2000 Director Stock Option Plan (the "Plan") of Curis,
Inc. (the "Company") is to encourage ownership in the Company by non-employee
directors of the Company whose continued services are considered essential to
the Company's future progress and to provide them with a further incentive to
remain as directors of the Company.
2. Administration.
---------------
The Board of Directors (the "Board") shall supervise and administer the
Plan. All questions concerning interpretation of the Plan or any options
granted under it shall be resolved by the Board and such resolution shall be
final and binding upon all persons having an interest in the Plan. The Board
may, to the full extent permitted by or consistent with applicable laws or
regulations, delegate any or all of its powers under the Plan to a committee
appointed by the Board, and if a committee is so appointed, all references to
the Board in the Plan shall mean and relate to such committee.
3. Participation in the Plan.
--------------------------
Directors of the Company who are not employees of the Company or any
subsidiary of the Company ("non-employee directors") shall be eligible to
receive options under the Plan.
4. Stock Subject to the Plan.
--------------------------
(a) The maximum number of shares of the Company's common stock, par value
$0.01 per share ("Common Stock"), which may be issued under the Plan shall be
500,000 shares, subject to adjustment as provided in Section 7.
(b) If any outstanding option under the Plan for any reason expires or is
terminated without having been exercised in full, the shares covered by the
unexercised portion of such option shall again become available for issuance
pursuant to the Plan.
(c) All options granted under the Plan shall be non-statutory options not
entitled to special tax treatment under Section 422 of the Internal Revenue Code
of 1986, as amended (the "Code").
(d) Shares issued under the Plan may consist in whole or in part of
authorized but unissued shares or treasury shares.
<PAGE>
5. Terms, Conditions and Form of Options.
--------------------------------------
Each option granted under the Plan shall be evidenced by a written
agreement in such form as the Board shall from time to time approve, which
agreements shall comply with and be subject to the following terms and
conditions:
(a)(i) Automatic Option Grant Dates. Options shall automatically be
----------------------------
granted to all non-employee directors as follows:
(x) each person who first becomes a non-employee director after the
closing date (the "Closing Date") of the registration of the Company's Common
Stock pursuant to an effective registration statement under the Securities Act
of 1933, as amended, shall be granted an option to purchase 25,000 shares of
Common Stock on the date of his or her initial election to the Board; and
(y) each non-employee director shall be granted an option to
purchase 5,000 shares of Common Stock on the date of each Annual Meeting of
Stockholders of the Company following the Closing Date commencing with the 2001
Annual Meeting of Stockholders (other than a director who was initially elected
to the Board at any such Annual Meeting or, if previously, at any time after the
prior year's Annual Meeting of Stockholders), provided that he or she is serving
as a director immediately following the date of such Annual Meeting.
(ii) Periodic Grants of Options. Subject to execution by the non-
--------------------------
employee director of an appropriate option agreement, the Board may grant
additional options to purchase a number of shares to be determined by the Board
in recognition of services provided by a non-employee director in his or her
capacity as a director, provided that such grants are in compliance with the
requirements of Rule 16b-3, as promulgated under the Securities Exchange Act of
1934, as amended from time to time.
Each date of grant of an option pursuant to this Section 5(a) is hereinafter
referred to as an "Option Grant Date."
(b) Option Exercise Price. The option exercise price per share for
---------------------
each option granted under the Plan shall equal (i) the closing price on any
national securities exchange on which the Common Stock is listed, (ii) the
closing price of the Common Stock on the Nasdaq National Market or (iii) the
average of the closing bid and asked prices in the over-the-counter market,
whichever is applicable, as published in The Wall Street Journal, on the Option
-----------------------
Grant Date. If no sales of Common Stock were made on the Option Grant Date, the
price of the Common Stock for purposes of clauses (i) and (ii) above shall be
the reported price for the next preceding day on which sales were made.
(c) Transferability of Options. Except as the Board may otherwise
--------------------------
determine or provide in an option granted under the Plan, any option granted
under the Plan to an optionee shall not be transferable by the optionee other
than by will or the laws of descent and distribution or pursuant to a qualified
domestic relations order as defined by the Code or Title I of the Employee
Retirement Income Security Act, or the rules thereunder, and shall be
exercisable
-2-
<PAGE>
during the optionee's lifetime only by the optionee or the optionee's guardian
or legal representative. References to an optionee, to the extent relevant in
the context, shall include references to authorized transferees. Notwithstanding
the foregoing, options may be transferred by non-employee directors (i) to a
spouse, lineal ancestor or descendant, brother or sister of such Participant and
to any trust for the benefit of such persons and (ii) as gifts to charitable
organizations within the meaning of Section 501(c)(3) of the Code, so long as
any such transferee agrees to be bound by the terms of such written
instrument(s) as the Board shall determine.
(d) Vesting Period.
--------------
(i) General. Each option granted under the Plan pursuant to Section
-------
5(a)(i)(x) above shall become exercisable (vest) in four equal annual
installments beginning on earlier of (A) the first anniversary of such Option
Grant Date and (B) the day before the Annual Meeting of Stockholders of the
applicable anniversary year . Each option granted under the Plan pursuant to
Section 5(a)(i)(y) above shall become exercisable in full upon the Option Grant
Date. No further vesting shall occur with respect to an option granted pursuant
to Section 5(a)(i)(x) after the optionee ceases to be a non-employee director of
the Company. Each option granted under the Plan pursuant to Section 5(a)(ii)
above shall become exercisable on such terms as shall be determined by the Board
and set forth in the option agreement with the respective optionee.
(ii) Acceleration Upon Acquisition Event. Notwithstanding the
-----------------------------------
foregoing, each outstanding option granted under the Plan shall immediately
become exercisable in full immediately prior to the occurrence of an Acquisition
Event (as defined in Section 8) with respect to the Company.
(iii) Right to Receive Restricted Stock. Notwithstanding the provisions
---------------------------------
of Section 5(d)(i) above, the Board shall have the authority to grant options
(including options granted pursuant to Section 5(a)(i) above) which are
immediately exercisable subject to the Company's right to repurchase any
unvested shares of stock acquired by the optionee on exercise of an option in
the event such optionee's service as a director terminates for any reason.
(e) Termination. Each option shall terminate, and may no longer be
-----------
exercised, on the earlier of (i) the date ten years after the Option Grant Date
of such option or (ii) the first anniversary of the date on which the optionee
ceases to serve as a director of the Company; provided, however, that in the
event that a non-employee director has served as a director of the Company for
at least five years, each option held by such director shall terminate, and may
no longer be exercised, on the date ten years after the Option Grant Date of the
applicable option.
(f) Exercise Procedure. An option may be exercised only by written
------------------
notice to the Company at its principal office accompanied by (i) payment in cash
or by certified or bank check of the full consideration for the shares as to
which they are exercised, (ii) delivery of outstanding shares of Common Stock
(which have been outstanding for at least six months) having a fair market value
on the last business day preceding the date of exercise equal to the option
exercise price, (iii) an irrevocable undertaking by a creditworthy broker to
deliver promptly to the
-3-
<PAGE>
Company sufficient funds to pay the exercise price or delivery of irrevocable
instructions to a creditworthy broker to deliver promptly to the Company cash or
a check sufficient to pay the exercise price, (iv) delivery of a promissory note
to the Company on terms determined by the Board or (v) any combination of the
above permitted terms of payment.
(g) Exercise by Representative Following Death of Director. An optionee,
------------------------------------------------------
by written notice to the Company, may designate one or more persons (and from
time to time change such designation), including his or her legal
representative, who, by reason of the optionee's death, shall acquire the right
to exercise all or a portion of the option. If the person or persons so
designated wish to exercise any portion of the option, they must do so within
the term of the option as provided herein. Any exercise by a representative
shall be subject to the provisions of the Plan.
6. Limitation of Rights.
---------------------
(a) No Right to Continue as a Director. Neither the Plan, nor the
----------------------------------
granting of an option nor any other action taken pursuant to the Plan, shall
constitute or be evidence of any agreement or understanding, express or implied,
that the Company will retain the optionee as a director for any period of time.
(b) No Stockholders' Rights for Options. An optionee shall have no rights
-----------------------------------
as a stockholder with respect to the shares covered by his or her option until
the date of the issuance to him or her of a stock certificate therefor, and no
adjustment will be made for dividends or other rights (except as provided in
Section 7) for which the record date is prior to the date such certificate is
issued.
(c) Compliance with Securities Laws. Each option shall be subject to the
-------------------------------
requirement that if, at any time, counsel to the Company shall determine that
the listing, registration or qualification of the shares subject to such option
upon any securities exchange or under any state or federal law, or the consent
or approval of any governmental or regulatory body, or the disclosure of non-
public information or the satisfaction of any other condition is necessary as a
condition of, or in connection with, the issuance or purchase of shares
thereunder, such option may not be exercised, in whole or in part, unless such
listing, registration, qualification, consent or approval, or satisfaction of
such condition shall have been effected or obtained on conditions acceptable to
the Board. Nothing herein shall be deemed to require the Company to apply for
or to obtain such listing, registration or qualification, or to satisfy such
condition.
7. Adjustment Provisions for Mergers, Recapitalizations and Related
----------------------------------------------------------------
Transactions.
-------------
If, through or as a result of any merger, consolidation, reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split, or other similar transaction, (i) the outstanding shares of Common Stock
are exchanged for a different number or kind of securities of the Company or of
another entity, or (ii) additional shares or new or different shares or other
securities of the Company or of another entity are distributed with respect to
such shares of Common Stock, the Board shall make an appropriate and
proportionate adjustment in (x) the
-4-
<PAGE>
maximum number and kind of shares reserved for issuance under the Plan, (y) the
number and kind of shares or other securities subject to then outstanding
options under the Plan, and (z) the price for each share subject to any then
outstanding options under the Plan (without changing the aggregate purchase
price for such options), to the end that each option shall be exercisable, for
the same aggregate exercise price, for such securities as such option holder
would have held immediately following such event if he had exercised such option
immediately prior to such event. No fractional shares will be issued under the
Plan on account of any such adjustments.
8. Acquisition Event.
------------------
For purposes of the Plan, an "Acquisition Event" shall be deemed to have
occurred only if any of the following events occurs: (i) any merger or
consolidation which results in the voting securities of the Company outstanding
immediately prior thereto representing immediately thereafter (either by
remaining outstanding or by being converted into voting securities of the
surviving or acquiring entity) less than 50% of the combined voting power of the
voting securities of the Company or such surviving or acquiring entity
outstanding immediately after such merger or consolidation; (ii) any sale of all
or substantially all of the assets of the Company; or (iii) the complete
liquidation of the Company.
9. Termination and Amendment of the Plan.
--------------------------------------
The Board may suspend or terminate the Plan or amend it in any respect
whatsoever.
10. Notice.
-------
Any written notice to the Company required by any of the provisions of the
Plan shall be addressed to the Treasurer of the Company and shall become
effective when it is received.
11. Governing Law.
--------------
The Plan and all determinations made and actions taken pursuant hereto
shall be governed by the internal laws of the State of Delaware (without regard
to any applicable conflicts of laws or principles).
12. Effective Date.
---------------
The Plan shall take effect upon the Closing Date.
Adopted by the Board of Directors on
_________, 2000.
Approved by the Stockholders on
_________, 2000.
-5-