CYTOGEN CORP, S-3/A, 1998-02-26

CYTOGEN CORP
S-3/A, 1998-02-26
IN VITRO & IN VIVO DIAGNOSTIC SUBSTANCES

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As filed with the Securities and Exchange Commission on February 26, 1998

Registration No. 333-43809

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
------------------
AMENDMENT NO. 1
TO
FORM S-3
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
------------------

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

Delaware 22-2322400
(State or Other Jurisdiction of (I.R.S. Employer
Incorporation or Organization) Identification No.)

600 College Road East
Princeton, New Jersey 08540
(609) 987-8200
(Address, Including ZIP Code, and Telephone Number, Including Area
Code, of Registrant's Principal Executive Offices)
------------------

DONALD F. CRANE, JR., ESQ.
VICE PRESIDENT
GENERAL COUNSEL AND
CORPORATE SECRETARY
CYTOGEN CORPORATION
600 College Road East
Princeton, New Jersey 08540
(609) 987-8200
(Name, Address, Including ZIP Code, and Telephone Number,
Including Area Code, of Agent for Service)
------------------

Copy to:
FREDERICK W. KANNER, ESQ.
DEWEY BALLANTINE LLP
1301 Avenue of the Americas
New York, New York 10019-6092
(212) 259-8000
--------------------

<PAGE>

Approximate date of commencement of proposed sale to the public: From time
to time after the effective date of this Registration Statement.

If the only securities being registered on this form are being offered
pursuant to dividend or interest reinvestment plans, please check the
following box. [ ]

If any of the securities being registered on this form are to be offered
on a delayed or continuous basis pursuant to Rule 415 under the
Securities Act of 1933, other than Securities offered only in connection
with dividend or interest reinvestment plans, check the following box.
[ X ]

If this Form is filed to register additional Securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the
following box and list the Securities Act registration statement number
of the earlier effective registration statement for the same offering.
[ ]

If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the
Securities Act registration statement number of the earlier effective
registration statement for the same offering. [ ]

If delivery of the prospectus is expected to be made pursuant to Rule
434, please check the following box. [ ]

CALCULATION OF REGISTRATION FEE
-------------------------------

Title of Shares to Proposed Maximum Proposed Amount of
be Registered Amount Aggregate Price Per Maximum Registration
Common Registered Share (1) Aggregate Fee
stock,par 6,000,000 (2) $1.61 Offering $1,884
value $.01 Price
per share $9,660,000

(1) Estimated solely for purposes of computing the registration fee
pursuant to Rule 457(c).

(2) Pursuant to Rule 416 under the Securities Act of 1933, any
additional shares of Common Stock issued as a result of the anti-dilution
provisions of the Certificate of Designation relating to the
Preferred Stock pursuant to which the Common Stock will be issued are
deemed to be registered herewith.

The Registrant hereby amends this Registration Statement on such date
or dates as may be necessary to delay its effective date until the
Registrant shall file a further amendment which specifically states
that this Registration Statement shall thereafter become effective in
accordance with Section 8(a) of the Securities Act of 1933 or until
the Registration Statement shall become effective on such date as the
Commission, acting pursuant to said Section 8(a), may determine.

2
<PAGE>

SUBJECT TO COMPLETION, DATED FEBRUARY 24, 1998

6,000,000 Shares

CYTOGEN CORPORATION

COMMON STOCK

This Prospectus relates to up to 6,000,000 shares of Common Stock,
par value $.01 per share (the "Common Stock"), of CYTOGEN Corporation
("CYTOGEN" or the "Company"), which have been registered for sale from
time to time by the selling stockholders named herein or their permitted
transferees or successors (the "Selling Stockholders"). Any or all of
the Common Stock being registered hereby may be sold from time to time
to purchasers directly by the Selling Stockholders. Alternatively, the
Selling Stockholders may from time to time offer the Common Stock
through underwriters, dealers or agents who may receive compensation in
the form of underwriting discounts, concessions or commissions from the
Selling Stockholders and/or the purchasers of Common Stock for whom they
may act as agent. To the extent required, the names of the Selling
Stockholders, the number of shares of Common Stock to be sold, purchase
price, public offering price, the name of any agent, dealer or
underwriter and any applicable commission or discount or other items
constituting compensation or indemnification arrangements with respect
to a particular offering will be set forth in an accompanying Prospectus
Supplement. The Company will receive no proceeds from sales by the
Selling Stockholders of the Common Stock offered hereby. The shares of
Common Stock to which this Prospectus relates are issuable to the
Selling Stockholders from time to time upon conversion of or as
dividends on certain securities received in the Private Placement (as
defined herein). All Registration Expenses (as defined herein) incurred
in connection with the registration of the Common Stock to which this
Prospectus relates will be borne by the Company. The Company has agreed
to indemnify the Selling Stockholders against certain liabilities,
including certain liabilities under the Securities Act of 1933, as
amended (the "Securities Act"), or to contribute to payments which the
Selling Stockholders may be required to make in respect thereof. See
"Plan of Distribution."

The Common Stock is traded on the Nasdaq National Market under the
symbol "CYTO." The last reported sale price of the Common Stock as
reported by the Nasdaq National Market on January 5, 1998 was $1.91 per
share.

The Common Stock offered hereby involves a high degree of risk. See
"Risk Factors" beginning on page 5 for a discussion of certain factors
that should be considered by prospective investors.

---------------------
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION
PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY
REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
----------------------

<PAGE>

The date of this Prospectus is February , 1998.

Information contained herein is subject to completion or amendment.
A registration statement relating to these Securities has been filed
with the Securities and Exchange Commission. These Securities may not
be sold nor may offers to buy be accepted prior to the time the
registration statement becomes effective. This prospectus shall not
constitute an offer to sell or the solicitation of an offer to buy nor
shall there be any sale of these Securities in any State in which such
offer, solicitation or sale would be unlawful prior to registration or
qualification under the Securities laws of any such state.

AVAILABLE INFORMATION
---------------------

The Company is subject to the informational requirements of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), and
in accordance therewith files reports, proxy statements and other
information with the Securities and Exchange Commission (the
"Commission"). The Company has filed a Registration Statement on Form
S-3 with the Commission under the Securities Act with respect to the
Common Stock offered hereby. As permitted by the rules and regulations
of the Commission, this Prospectus omits certain information contained
in the Registration Statement. For further information, reference is
made to the Registration Statement, including the financial schedules
and exhibits incorporated therein by reference or filed as a part
thereof. Such reports, proxy statements and other information can be
inspected and copied at the public reference facilities maintained by
the Commission at 450 Fifth Street, N.W., Judiciary Plaza, Room 1024,
Washington, D.C. 20549, and at the Commission's following Regional
Offices: Citicorp Center, 500 West Madison Street, Suite 1400, Chicago,
Illinois 60661-2511; and Seven World Trade Center, 13th Floor, New York,
New York 10048. Copies of such material can be obtained at prescribed
rates from the Public Reference Section of the Commission at 450 Fifth
Street, N.W., Judiciary Plaza, Washington, D.C. 20549. Reports, proxy
statements and other information filed electronically by the Company
with the Commission are available at the Commission's world wide web
site at http://www.sec.gov. The Company's Common Stock is traded on the
Nasdaq National Market under the symbol "CYTO," and reports, proxy
statements and other information concerning the Company also may be
inspected at the offices of the National Association of Securities
Dealers, Inc., 1735 K Street, N.W., Washington, D.C. 20006. Statements
made in this Prospectus as to the contents of any contract, agreement
or other document referred to are not necessarily complete, and, in each
instance, reference is made to the copy of such document filed as an
exhibit to the Registration Statement or otherwise filed with the
Commission. Each such statement shall be deemed qualified in its
entirety by such reference. The Company maintains a world wide web site
at http://www.cytogen.com.

<PAGE>

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
-----------------------------------------------

The following documents have been filed with the Commission by the
Company and are incorporated herein by reference in this Prospectus and
made a part hereof: (i) the Company's Annual Report on Form 10-K for
the year ended December 31, 1996; (ii) the Company's Quarterly Reports
on Form 10-Q for the quarters ended March 31, 1997, June 30, 1997 and
September 30, 1997; and (iii) the Company's Current Reports on Form 8-K
dated July 8, 1997 and December 22, 1997; and (iv) all documents filed
by the Company pursuant to Section 13(a), 13(c), 14 or 15(d) of the
Exchange Act after the date of this Prospectus and prior to the
termination of the offering of the Common Stock shall be deemed to be
incorporated by reference in this Prospectus and to be a part hereof
from the date of filing such documents. Any statement contained in a
document incorporated or deemed to be incorporated by reference herein
shall be deemed to be modified or superseded for purposes of this
Prospectus to the extent that a statement contained herein or in any
other subsequently filed document which also is or is deemed to be
incorporated by reference herein modifies or supersedes such statement.
Any statement so modified or superseded shall not be deemed, except as
so modified or superseded, to constitute a part of this Prospectus.
The Company will provide without charge to each person to whom this
Prospectus is delivered, upon the request of such person, a copy of any
or all of the foregoing documents incorporated herein by reference,
other than exhibits to such documents (unless such exhibits are
specifically incorporated by reference into such documents). Requests
for such documents should be submitted in writing to Cytogen
Corporation, Attention: Investor Relations, 600 College Road East, CN
5308, Princeton, New Jersey 08540-5308, Telephone: (609) 987-8200.
--------------------

No person has been authorized in connection with the offering made
hereby to give any information or make any representation not contained
in this Prospectus and, if given or made, such information or
representation must not be relied upon as having been authorized by the
Company or any other person. This Prospectus does not constitute an
offer to sell or solicitation of any offer to buy any of the Securities
offered hereby in any jurisdiction in which it is unlawful to make such
offer or solicitation. Neither the delivery of this Prospectus nor any
sale made hereunder shall, under any circumstances, create any
implication that the information contained herein is correct as of any
date subsequent to the date hereof.

RISK FACTORS
------------

Prospective investors in the Common Stock offered hereby should
carefully consider the following risk factors, in addition to the other
information contained in this Prospectus and the documents incorporated
herein. This Prospectus contains forward-looking statements which
involve risks and uncertainties. The Company's actual results could
differ materially from those anticipated in these forward-looking
statements as a result of certain factors, including those set forth in
the following risk factors and elsewhere in this Prospectus and the
documents incorporated herein by reference.

<PAGE>

History of Operating Losses; Accumulated Deficit; Uncertainty of
- ----------------------------------------------------------------
Profitability; Fluctuating Results of Operations
- ------------------------------------------------
The Company has incurred substantial operating losses since
inception and, as of September 30, 1997, had an accumulated deficit of
approximately $278 million. During 1996 and the nine months ended
September 30, 1997, the Company incurred net losses of $23,766,000 and
$26,092,000 respectively and operating losses of $24,862,000 and
$26,647,000, respectively. Such losses have resulted principally from
expenses incurred in the Company's research and development activities,
including, without limitation, the acquisition of complementary products
and technologies, seeking regulatory approvals, related preclinical and
clinical studies and the preparation of submissions to the United States
Food and Drug Administration (the "FDA"), development of sales,
marketing, manufacturing and distribution channels, development of
internal manufacturing capabilities relating to ProstaScint, and general
and administrative expenses. The Company expects to incur significant
operating losses in the future primarily due to the Company's continued
research and product development efforts, costs associated with the
acquisition of complementary products and technologies and their related
development and commercialization expenses, and the further expansion
of the Company's sales, marketing, manufacturing and distribution
activities. The Company's ability to achieve and maintain profitability
is highly dependent upon the successful commercialization of its
products, including Quadramet and ProstaScint, and the successful
completion of the research and development of, the obtaining of
regulatory approvals for, and the successful commercialization of, its
product candidates, including Autologous Lymphocyte Therapy ("ALT").
Further, the markets targeted by the Company are heavily regulated and
are characterized by an increasing number of entrants, intense
competition and a high rate of failure. There can be no assurance that
the Company will ever be able to successfully commercialize its products
or that profitability will ever be achieved. The Company's results of
operations have fluctuated in the past on an annual and quarterly basis
and may fluctuate significantly from period to period in the future,
depending upon a number of factors, including, without limitation, the
degree of market acceptance of the Company's products, the timing of
regulatory approvals and other regulatory announcements, variations in
the Company's sales, marketing, manufacturing and distribution channels,
the timing and successful integration of acquired complementary products
and technologies, the timing of new product announcements and
introductions by the Company and its competitors, product obsolescence
resulting from new product introductions and other factors, many of
which are outside the Company's control. Due to one or more of the
aforementioned factors, in one or more future quarters the Company's
results of operations may fall below the expectations of securities
analysts and investors. In that event, the market price of the
Company's Common Stock could be materially and adversely affected.

Future Capital Needs; Uncertainty of Additional Financing
- ---------------------------------------------------------
The Company has incurred negative cash flows from operations since
its inception, and has expended, and expects to continue to expend in
the future, substantial funds to complete its planned product
development efforts, including acquisition of products and complementary
technologies, research and development, clinical studies and regulatory
activities, and to further expand its marketing, sales, manufacturing
and distribution activities. The Company expects that its existing
capital resources will be adequate to fund the Company's operations
through at least mid-1998. No assurance can be given that the Company
will not consume a significant amount of its available resources before
that time. In addition, the Company expects that it will have
additional requirements for debt or equity capital, irrespective of
whether and when it reaches profitability, for further development of
products, product and technology acquisition costs, and working capital.
The Company's future capital requirements and the adequacy of available
funds will depend on numerous factors, including the successful

<PAGE>

commercialization of its products, the costs associated with the
acquisition of complementary products and technologies, progress in its
product development efforts, the magnitude and scope of such efforts,
progress with preclinical studies and clinical trials, progress with
regulatory affairs activities, the cost of filing, prosecuting,
defending and enforcing patent claims and other intellectual property
rights, competing technological and market developments, and the
expansion of strategic alliances for the sales, marketing, manufacturing
and distribution of its products. To the extent that funds generated
from the Company's product-related sales and license and contract
revenues, together with its existing capital resources are insufficient
to meet current or planned operating requirements, the Company will be
required to obtain additional funds through equity or debt financing,
strategic alliances with corporate partners and others, or through other
sources. The Company has a commitment pursuant to which it may issue
up to $12.5 million in additional series of convertible preferred stock,
under certain conditions, however, there can be no assurance that such
conditions will be met. If adequate funds are not available, the Company
may be required to delay, scale back or eliminate certain aspects of its
operations or attempt to obtain funds through arrangements with
collaborative partners or others that may require the Company to
relinquish rights to certain of its technologies, product candidates,
products or potential markets. If adequate funds are not available, the
Company's business, financial condition and results of operations will
be materially and adversely effected.

Dependence on Quadramet and ProstaScint
- ---------------------------------------
No significant history of revenues exists with respect to any of
the Company's products. Quadramet and ProstaScint were introduced to the
market during the first half of 1997 and are expected to account for a
significant percentage of the Company's product related revenues for the
foreseeable future. For the quarter ended September 30, 1997, revenues
related to Quadramet and ProstaScint accounted for over 89% of the
Company's product related revenues. There can be no assurance that
Quadramet and ProstaScint will achieve market acceptance. The Company's
success will be dependent upon the acceptance of Quadramet and
ProstaScint by the medical community (including health care providers
such as hospitals and physicians), and third-party payors (including
Medicare, Medicaid, private insurance carriers and health maintenance
organizations) as safe, effective and cost efficient alternatives to
other available treatment and diagnostic protocols. DuPont Merck is
responsible for marketing Quadramet to managed care organizations ("MCOs"),
while CYTOGEN and BARD market ProstaScint to the MCOs. CYTOGEN's focus is
to increase the MCOs awareness of and to obtain coverage for ProstaScint
while BARD is working with the MCOs to incorporate ProstaScint in the MCOs'
patient practice guidelines. The Company believes that marketing
efforts to hospitals and physicians have been well received. There can be
no assurance that Quadramet or ProstaScint will achieve market acceptance
on a timely basis, or at all. The failure of Quadramet or ProstaScint to
achieve market acceptance would have a material adverse effect on the
Company's business, financial condition and results of operations.
Furthermore, the use of certain of the Company's products requires varying
degrees of training by physicians, technicians and other health care
professionals prior to usage for diagnosis or therapy. In particular, the
approved indication for ProstaScint requires the medical imaging community,
including technologists and physicians, to successfully complete the Company's
Partner's in Excellence Program ("PIE" Program), a proprietary training
program which is designed to ensure appropriate acquisition and
interpretation of ProstaScint images. The successful completion of such
program generally takes up to one month, requires annual maintenance
certification and has an enrollment backlog of approximately eight
months. The backlog for enrollment may have had and may continue to
have an impact on sales, although the Company cannot quantify the amount
of sales which could have been or could be obtained without the backlog.
The Company incurs the costs of training physicians in the
administration of and diagnosis using ProstaScint. The failure of such
health care professionals to devote adequate time or resources for such
education or training could delay the market acceptance of such
products, particularly ProstaScint, and could have a material adverse

<PAGE>

effect on the Company's business, financial condition and results of
operations. The Company has licensed the rights to Quadramet from Dow
Chemical pursuant to a license agreement expiring on the later or May
13, 2013 or upon the expiration of patents covering Quadramet. Such
rights are currently limited to North, South and Central America. There
can be no assurance that Quadramet or ProstaScint will be accepted in
any markets outside the United States due to the influence of
established medical practices, and other social and economic factors
beyond the Company's control.

Dependence on Receipt of Regulatory Approvals for, and Successful
- -----------------------------------------------------------------
Commercialization of, ALT
- -------------------------
The Company has recently completed Phase III clinical trials
relating to ALT and intends to file a Biologics License Application
("BLA") with the FDA during early 1998. The Company's success will be
dependent upon its ability to receive timely approval from the FDA for
the marketing of ALT for its proposed indications. The FDA approval
process is unpredictable and uncertain, and no assurance can be given
that the necessary approvals or clearances for ALT will be granted in
a timely manner, or at all. Delays in the receipt of, of a failure to
receive, such approvals or clearances for ALT could have a material
adverse effect on the Company's business, financial condition and
results of operations. Further, if approved by the FDA, there can be
no assurance that ALT will achieve market acceptance by the medical
community, including health care providers, such as hospitals and
physicians, and third-party payors, as a safe, effective and cost
efficient alternative to other available treatment protocols. The
failure of ALT to receive timely approval for its proposed indications
and to thereafter be successfully commercialized would have a material
adverse effect on the Company's business, financial condition and
results of operations.

Dependence on Collaborative Partners
- ------------------------------------
The Company has entered into collaborative and licensing
arrangements with large pharmaceutical companies, licensees and third
parties with respect to the manufacture, sales, marketing and
distribution of certain of the Company's products and product candidates
and technologies. In particular, the Company has entered into a sub-license
with The DuPont Merck Pharmaceutical Company ("DuPont Merck")
relating to the Quadramet technology the Company licensed from Dow
Chemical under the sub-license. DuPont Merck is responsible for
manufacturing, marketing, selling and distributing Quadramet in its
oncological applications in the United States. Under the sub-license,
the Company may promote Quadramet to nuclear medicine specialists,
although it has not engaged in such co-promotion to date. This sub-license
expires on the later of December 20, 2014 or upon the expiration
of the patents covering Quadramet. In addition, the Company is party
to a co-promotion agreement with C.R. BARD, Inc. ("BARD"), pursuant to
which BARD's Urological Division has the exclusive right to market
ProstaScint to urologists. As a result, these aspects of the Company's
sales, marketing, manufacturing and distribution activities will be
outside the direct control of the Company. There can be no assurance
that DuPont Merck or BARD will perform all of their obligations under
their arrangements with the Company. In addition, there can be no
assurance that any such arrangements will be renewed or any new
arrangements will be available on acceptable terms, if at all, or that
any such arrangements, if entered into, will be successful. In the
event that DuPont Merck or BARD do not successfully sell, market,
manufacture and distribute Quadramet and ProstaScint, respectively, or
breach their obligations to the Company, the successful
commercialization of Quadramet and ProstaScint would be delayed, which
could have a material adverse effect on the Company's business,
financial condition and results of operations. Accordingly, the
Company's success with respect to Quadramet and ProstaScint will depend,
in significant part, upon the subsequent success of the efforts of
DuPont Merck and BARD. Further, the Company is dependent upon the
efforts of Elan Corporation, plc ("Elan") in connection with the
development of product candidates, including a collaboration with

<PAGE>

respect to a synthetic peptide developed with the Company's proprietary
Genetic Diversity Library ("GDL") technology and as to various products
in development by Targon Corporation ("Targon"), a subsidiary of the
Company which is managed and funded jointly by the Company and Elan.
(See "Business of the Company" for a further description of GDL
technology.) The failure by Elan to perform its obligations under
agreements with the Company would delay or preclude the development of
certain of the Company's product candidates, which could have a material
adverse effect on the Company's business, financial condition and
results of operations.

There can be no assurance that the Company will be able to maintain
its existing collaborative arrangements or enter into collaborative and
license arrangements in the future on acceptable terms, if at all, that
such arrangements will be successful, that the parties with which the
Company has or may establish arrangements will perform their obligations
under such arrangements, or that potential collaborators will not
compete with the Company by seeking alternative means of developing
products for the indications targeted by the Company. There can also
be no assurance that the Company's existing or any future arrangements
will lead to the development of product candidates or technologies with
commercial potential, that the Company will be able to obtain
proprietary rights or licenses for the proprietary rights with respect
to any product candidates or technologies developed in connection with
these arrangements, or that the Company will be able to ensure the
confidentiality of any proprietary rights and information developed in
such arrangements or prevent the public disclosure thereof.

Limited Sales, Marketing and Distribution Capabilities
- ------------------------------------------------------
The Company has limited internal sales, marketing and distribution
capabilities. With respect to the sales, marketing and distribution of
Quadramet and ProstaScint, the Company is substantially dependent on the
efforts of DuPont Merck and BARD, respectively. Failure to successfully
establish and maintain significant sales, marketing and distribution
efforts, either internally or through arrangements with third parties,
would have a material adverse effect on the Company's business,
financial condition and results of operations.

Limited Marketing History
- -------------------------
The Company has a limited marketing history for its principal
commercial products, ProstaScint and Quadramet. ProstaScint was
approved for marketing by the FDA in October, 1996, and commercially
launched in February, 1997. Quadramet was approved for marketing by the
FDA in March 1997 and launched by DuPont Merck in June, 1997.
ProstaScint sales have experienced continued growth since product
launch, with sales increases during each successive quarter. However,
there can be no assurance that such growth will continue indefinitely.
Quadramet sales during the period from its initial launch have been
below the levels of minimum royalty payments. Growth during early
months was limited by the need for hospitals to obtain license
amendments under federal and state law to receive and handle this new
radioactive product. In addition, initial marketing efforts by the
Company's commercial partner, DuPont Merck, were directed to nuclear
medicine physicians who directly administer the product to patients.
While management believes this additional sales effort was necessary to
generate product awareness, the Company believes that marketing to
oncologists and urologists, the primary caregivers for likely candidates
for treatment with Quadramet, is necessary for extensive penetration
into the market. The failure of ProstaScint and Quadramet to achieve
commercial success could have a material adverse effect on the Company's
business and results of operations. In addition, the Company's ALT and
GDL products have not yet received marketing approval by the FDA. The
failure of ALT and GDL to receive marketing approval by the FDA could
have a material adverse effect on the Company's results of operations.

<PAGE>

Risks Associated with Manufacturing; Third-Party Manufacturers'
- ---------------------------------------------------------------
Dependence on Single Source Suppliers
- -------------------------------------
The Company's products must be manufactured either internally or
through third-party manufacturers in compliance with regulatory
requirements and at commercially acceptable costs. Quadramet is
manufactured by DuPont Merck pursuant to an agreement with CYTOGEN.
While the Company believes that its manufacturing operations currently
address the Company's needs for its other products, there can be no
assurance that the Company will be able to continue to manufacture such
products on a commercially reasonable basis, that the Company will have
the capacity to manufacture additional products and product candidates
or successfully outsource such manufacturing needs. The failure of the
Company to successfully manufacture or arrange for the manufacture of
its products and product candidates would have a material adverse effect
on the Company's business, financial condition and results of
operations.

In addition, certain components of Quadramet, particularly
Samarium-153 ("Sm-153") and EDTMP, are provided to DuPont Merck by sole
source suppliers. Due to its radiochemical properties, Sm-153 must be
produced on a weekly basis by its supplier in order to meet DuPont
Merck's manufacturing requirements. On one occasion, DuPont Merck was
unable to manufacture Quadramet on a timely basis due to the failure of
the sole source supplier to provide an adequate supply of Sm-153. In the
event that DuPont Merck is unable to obtain sufficient quantities of
such components on commercially reasonable terms, or in a timely manner,
DuPont Merck would be unable to manufacture Quadramet on a timely and
cost-competitive basis which could have a material adverse effect on the
Company's business, financial condition and results of operations. In
addition, alternative sources for certain of these components may not
be readily available. Thus, the loss by DuPont Merck of its sources for
such components could result in an interruption of supply and could have
a material adverse effect on the Company's business, financial condition
and results of operations.

The Company and its third party manufacturers are required to
adhere to FDA regulations setting forth requirements for current Good
Manufacturing Practices ("cGMP") and similar regulations in other
countries, which include extensive testing, control and documentation
requirements. Ongoing compliance with cGMP, labeling and other
applicable regulatory requirements is monitored through periodic
inspections and market surveillance by state and federal agencies,
including the FDA, and by comparable agencies in other countries.
Failure of the Company and its third-party manufacturers to comply with
applicable regulations could result in sanctions being imposed on the
Company, including fines, injunctions, civil penalties, failure of the
government to grant premarket clearance or premarket approval of drugs,
delays, suspension or withdrawal of approvals, seizures or recalls of
products, operating restrictions and criminal prosecutions.

Risks Associated with Reimbursement by Third-Party Payors
- ---------------------------------------------------------
The business, financial condition and results of operations of
biotechnology and pharmaceutical companies, including CYTOGEN, will
continue to be affected by the efforts of governments and other third-party
payors to contain or reduce the costs of healthcare through
various means. There have been, and the Company expects that there will
continue to be, a number of federal and state proposals to implement
government control of pricing and profitability of therapeutic and
diagnostic imaging agents. In addition, an increasing emphasis on
managed care has and will continue to increase the pressure on pricing
of these products. While the Company cannot predict whether such
legislative or regulatory proposals will be adopted or the effects such
proposals or managed care efforts may have on its business, the

<PAGE>

announcement of such proposals and the adoption of such proposals or
efforts could have a material adverse effect on the Company's business,
financial condition and results of operations. Further, to the extent
such proposals or efforts have a material adverse effect on other
companies that are prospective corporate partners for the Company, the
Company's ability to establish strategic alliances may be materially and
adversely affected. In addition, sales of the Company's products will
be dependent, in part, on the availability of reimbursement to the
consumer from third-party payors, including Medicare, Medicaid, and
private health insurance plans. Third-party payors are increasingly
challenging the prices charged for medical products and services. There
can be no assurance that the Company's products will be considered
cost-effective and that reimbursement to consumers will be available, will
continue to be available, or will be sufficient to allow the Company to
sell its products on a competitive basis. Reimbursement by a third-party
payor may depend on a number of factors, including the payor's
determination that the use of the Company's products are clinically
useful and cost-effective, medically necessary and not experimental or
investigational. Since reimbursement approval is required from each
payor individually, seeking such approvals can be a time consuming and
costly process which could require the Company to provide supporting
scientific, clinical and cost-effectiveness data for the use of the
Company's products to each payor separately. Failure of the Company to
secure adequate third party reimbursement for its products would have
a material adverse effect on its business, financial condition and
results of operations. ALT and GDL technology are, at present,
experimental. The GDL technology may or may not itself be subject of
an application for FDA approval, and may be used for the development of
products for which approval is sought. None of the Company's FDA
approved products are experimental.

Competition
- -----------
The biotechnology and pharmaceutical industries are subject to
intense competition, including competition from large pharmaceutical
companies, biotechnology companies and other companies, universities and
research institutions. Competition with the Company's existing
therapeutic products is posed by a wide variety of other firms,
including firms which provide products used in more traditional
treatments or therapies, such as external beam radiation, chemotherapy
agents, narcotic analgesics and radiopharmaceuticals. In addition, the
Company's existing and potential competitors may be able to develop
technologies that are as effective as, or more effective than those
offered by the Company, which would render the Company's products
noncompetitive or obsolete. Moreover, many of the Company's existing
and potential competitors have substantially greater financial,
marketing, sales, manufacturing, distribution and technological
resources than the Company. Such existing and potential competitors may
be in the process of seeking FDA or foreign regulatory approval for
their respective products or may also enjoy substantial advantages over
the Company in terms of research and development expertise, experience
in conducting clinical trials, experience in regulatory matters,
manufacturing efficiency, name recognition, sales and marketing
expertise and distribution channels. In addition, many of these
companies may have more experience in establishing third-party
reimbursement for their products. Accordingly, there can be no
assurance that the Company will be able to compete effectively against
such existing or potential competitors or that competition will not have
a material adverse effect on the Company's business, financial condition
and results of operations.

Uncertainty Relating to Licenses, Patents and Proprietary Rights
- ----------------------------------------------------------------
The Company is highly dependent upon its proprietary technology and
seeks to protect such technology through a combination of patents,
licenses and trade secrets. The Company has applied for and obtained
patent protection and has licensed other patents for certain proprietary
aspects of its technology and processes in the U.S. and in other
countries. In particular, the Company is dependent upon the

<PAGE>

enforceability of its license with Dow with respect to the technology
underlying its Quadramet product. There can be no assurance that the
Company's owned and licensed patents will prove to be enforceable or
that additional patents will be issued. Neither can assurance be given
that the technologies used by the Company do not infringe upon the
proprietary rights of others, although the Company is not aware of any
such infringement or any adverse claim. The Company could incur
substantial costs in seeking enforcement of its patents against
infringement or the unauthorized use of its trade secrets by others or
in defending itself against patent infringement claims by others.
Insofar as the Company also relies in part on trade secrets and
unpatented know-how to maintain its competitive position, there can be
no assurance that others will not independently develop similar or
superior technologies or that the Company's trade secrets and know-how
will not become known to others.

The Company's success will depend, in part, on its ability, and the
ability of its collaborators or licensors, to obtain protection for its
products and technologies under United States and foreign patent laws,
to preserve its trade secrets, and to operate without infringing the
proprietary rights of third parties. Because of the substantial length
of time and expense associated with bringing new products through
development to the marketplace, the biopharmaceutical industry places
considerable importance on obtaining, and maintaining, patent and trade
secret protection for new technologies, products and processes. The
Company has obtained rights to certain patents and patent applications
and may, in the future, obtain, or seek rights from third parties to
additional patents and patent applications. There can be no assurance
that patent applications relating to the Company's products or
technologies will result in patents being issued, that any issued
patents will afford adequate protection to the Company, or that such
patents will not be challenged, invalidated, infringed or circumvented.
Furthermore, there can be no assurance that others have not developed,
or will not develop, similar products or technologies that will compete
with those of the Company without infringing upon the Company's
intellectual property rights.

Legal standards relating to the scope of claims and the validity
of patents in the biopharmaceutical industry are uncertain and still
evolving, and no assurance can be given as to the degree of protection
that will be afforded any patents issued to, or licensed by, the
Company. There can be no assurance that, if challenged by others in
litigation, any patents assigned to or licensed by the Company will not
be found invalid. Furthermore, there can be no assurance that the
Company's activities would not infringe patents owned by others.
Defense and prosecution of patent matters can be expensive and
time-consuming and, regardless of whether the outcome is favorable to
the Company, can result in the diversion of substantial financial,
management and other resources. An adverse outcome could subject the
Company to significant liability to third parties, require the Company
to obtain licenses from third parties, or require the Company to cease
any related research and development activities and product sales. No
assurance can be given that any licenses required under any such patents
or proprietary rights would be made available on terms acceptable to the
Company, if at all. Moreover, the laws of certain countries may not
protect the Company's proprietary rights to the same extent as United
States law.

The Company's success also is dependent upon the skill, knowledge,
and experience of its scientific and technical personnel. To help
protect its rights, the Company requires all employees, consultants,
advisors and collaborators to enter into confidentiality agreements that
prohibit the disclosure of confidential information to anyone outside
the Company and require disclosure, and in most cases, assignment to the
Company, of their ideas, developments, discoveries and inventions.
There can be no assurance, however, that these agreements will provide

<PAGE>

adequate protection for the Company's trade secrets, know-how or other
proprietary information in the event of any unauthorized use or
disclosure.

Uncertainties Relating to Product Development
- ---------------------------------------------
Product development involves a high degree of risk. There can be
no assurance that the Company's product candidates will prove to be safe
and effective, will receive the necessary regulatory approvals or will
ultimately achieve market acceptance. These product candidates will
require substantial additional investment, laboratory development,
clinical testing and regulatory approvals prior to their
commercialization. There can be no assurance that the Company will not
experience difficulties that could delay or prevent the successful
development, introduction and marketing of new products. The Company's
inability to successfully develop and commercialize products on a timely
basis or at all, or achieve market acceptance of such products, could
have a material adverse effect on the Company's business, financial
condition and results of operations.

Before obtaining regulatory approvals for the commercial sale of
any of its products under development, the Company must demonstrate
through preclinical studies and clinical trials that the product is safe
and efficacious for use in each target indication. The results from
preclinical studies and early clinical trials may not be predictive of
results that will be obtained in large-scale testing, and there can be
no assurance that the Company's clinical trials will demonstrate the
safety and efficacy of any products or will result in marketable
products. A number of companies in the biotechnology industry have
suffered significant setbacks in advanced clinical trials, even after
promising results in earlier trials. In addition, there can be no
assurance that product issues will not arise following successful
clinical trials and FDA approval.

The rate of completion of the Company's clinical trials is
dependent upon, among other factors, the rate of patient enrollment.
Patient enrollment is a function of many factors, including the size of
the patient population, the nature of the protocol, the proximity of
patients to clinical sites and the eligibility criteria for the study.
Delays in planned patient enrollment may result in increased costs and
delays, which could have a material adverse effect on the Company.

Government Regulation
- ---------------------
Any products tested, manufactured or distributed by the Company or
on the Company's behalf pursuant to FDA clearances or approvals are
subject to pervasive and continuing regulation by numerous regulatory
authorities, including primarily the FDA. Changes in existing
requirements or adoption of new requirements or policies could adversely
affect the ability of the Company to comply with regulatory
requirements. Failure to comply with regulatory requirements could have
a material adverse effect on the Company's business, financial condition
and results of operations. There can be no assurance that the Company
will not be required to incur significant costs to comply with laws and
regulations in the future or that laws or regulations will not have a
material adverse effect upon the Company's business, financial condition
and results of operations.

The preclinical testing, clinical trials, manufacture and promotion
of any compounds developed by the Company or its collaborative partners
and the manufacturing and marketing of any drugs resulting therefrom are
subject to regulation by numerous federal, state and local governmental
authorities in the United States, principally the FDA, and by similar
agencies in other countries in which drugs developed by the Company or
its collaborative partners may be tested and marketed (each of such
federal, state, local and other authorities and agencies, a "Regulatory

<PAGE>

Agency"). The drug development and regulatory approval process is
lengthy, expensive, uncertain and subject to delays. In all
circumstances, approval of the use of previously unapproved
radioisotopes in certain of the Company's products requires approval of
either the Nuclear Regulatory Commission or equivalent state regulatory
agencies. A radioisotope is an unstable form of an element which
undergoes radioactive decay, thereby emitting radiation which may be
used, for example, to image or destroy harmful growths or tissue. There
can be no assurance that such approvals will be obtained on a timely
basis, or at all. Any compound developed by the Company or its
collaborative partners must receive Regulatory Agency approval before
it may be marketed as a drug in a particular country. The regulatory
process, which includes preclinical testing and clinical trials of each
compound in order to establish its safety and efficacy, varies from
country to country, can take many years and requires the expenditure of
substantial resources. Data obtained from preclinical and clinical
activities are susceptible to varying interpretations which could delay,
limit or prevent Regulatory Agency approval. In addition, delays or
rejections may be encountered based upon changes in Regulatory Agency
policy during the period of drug development and/or the period of review
of any application for Regulatory Agency approval for a compound.
Delays in obtaining Regulatory Agency approvals could adversely affect
the marketing of any products developed by the Company or its
collaborative partners, impose costly procedures upon the Company's and
its collaborative partners' activities, diminish any competitive
advantages that the Company or its collaborative partners may attain and
adversely affect the Company's ability to receive royalties.

There can be no assurance that, even after such time and
expenditures, Regulatory Agency approvals will be obtained for any
compounds developed by or in collaboration with the Company. Moreover,
if Regulatory Agency approval for a drug is granted, such approval may
entail limitations on the indicated uses for which it may be marketed
that could limit the potential market for any such drug. Furthermore,
if and when such approval is obtained, the marketing, manufacture,
labeling, storage and record keeping related to the Company's products
would remain subject to extensive regulatory requirements. Discovery
of previously unknown problems with a drug, its manufacture, or its
manufacturer may result in restrictions on such drug, manufacture or
manufacturer, including withdrawal of the drug from the market. Failure
to comply with regulatory requirements could, among other things, result
in fines, suspension of regulatory approvals, operating restrictions and
criminal prosecution.

Further, the U. S. Food, Drug and Cosmetics Act requires that the
Company's products be manufactured in FDA registered facilities subject
to inspection. The manufacturer must be in compliance with cGMP which
imposes certain procedural and documentation requirements upon the
Company and its manufacturing partners with respect to manufacturing and
quality assurance activities. Noncompliance with cGMP can result in,
among other things, fines, injunctions, civil penalties, recalls or
seizures of products, total or partial suspension of production, failure
of the government to grant premarket clearance or premarket approval for
drugs, withdrawal of marketing approvals and criminal prosecution. Any
failure by the Company or its manufacturing partners to comply with the
requirements of cGMP could have a material adverse effect on the
Company's business, financial condition and results of operations.

Attraction and Retention of Key Personnel
- -----------------------------------------
The Company is highly dependent on the principal members of its
scientific and management staff, the loss of whose services might
significantly delay or prevent the achievement of research, development
or strategic objectives. The Company's success will depend on its

<PAGE>

ability to retain key employees and to attract additional qualified
employees. Competition for such personnel is intense, and there can be
no assurance that the Company will be able to retain existing personnel
and to attract, assimilate or retain additional highly qualified
employees in the future. None of the Company's key personnel have
employment agreements with the Company. If the Company is unable to
hire and retain personnel in key positions, such inability would have
a material adverse effect on the Company's business, financial condition
and results of operations.

Management Succession
- ---------------------
The Company has recently announced that Dr. John E. Bagalay, a
member of the Board of Directors, has been elected to serve as President
and Chief Executive Officer on an interim basis pending recruitment of
a candidate for the Chief Executive Officer position. Dr. Thomas J.
McKearn, the Company's previous Chairman, President and Chief Executive
Officer resigned that position and returned to a scientific role in the
Company. Mr. William C. Mills III was elected Chairman of the Board of
Directors, a role previously occupied from January, 1995 to May, 1996.
The Board of Directors of the Company (the "Board of Directors") is
currently engaged in a search for a Chief Executive Officer. No
assurance can be given as to the Company's ability to locate or secure
the employment of a suitably qualified candidate on a timely basis, or
at all. In addition, Dr. Bagalay is also serving as Chief Financial
Officer on an interim basis. The Board of Directors plans to conduct
a search for a permanent Chief Financial Officer following selection of
a new Chief Executive Officer, although no assurance can be given as to
the Company's ability to locate a suitable candidate for this position
on a timely basis, or at all.

Potential Inadequacy of Product Liability Insurance
- ---------------------------------------------------
The Company's business is subject to product liability risks
inherent in the testing, manufacturing and marketing of its products.
There can be no assurance that product liability claims will not be
asserted against the Company, its collaborators or licensees. While the
Company currently maintains product liability insurance in amounts it
believes are adequate, there can be no assurance that such coverage will
be adequate to protect the Company against future product liability
claims or that product liability insurance will be available to the
Company in the future on commercially reasonable terms, if at all.
Furthermore, there can be no assurance that the Company will be able to
avoid significant product liability claims and adverse publicity.
Consequently, a product liability claim or other claim with respect to
uninsured or underinsured liabilities could have a material adverse
effect on the Company's business, financial condition and results of
operations.

Environmental Regulation
- ------------------------
The Company is subject to a variety of local, state and federal
government regulations relating to the storage, discharge, handling,
emission, generation, manufacture and disposal of toxic, infectious or
other hazardous substances used to manufacture the Company's products.
Any failure by the Company to control the use, disposal, removal or
storage of hazardous chemicals or toxic substances could subject the
Company to significant liabilities, which could have a material adverse
effect on the Company's business, financial condition and results of
operations.

Volatility of Stock Price
- -------------------------
The market prices for securities of biotechnology and
pharmaceutical companies have historically been highly volatile, and the
market has from time to time experienced significant price and volume
fluctuations that are unrelated to the operating performance of
particular companies. The market price of the Company's Common Stock has
fluctuated over a wide range and may continue to fluctuate.

<PAGE>

Announcements concerning the Company or its competitors, including the
results of clinical trials, technological innovations or new commercial
products, changes in governmental regulation or the status of the
Company's regulatory approvals or applications, changes in earnings,
changes in health care policies and practices, developments or disputes
concerning proprietary rights, litigation or public concern as to safety
of the Company's potential products as well as changes in general market
conditions may have a significant effect on the market price of the
Company's Common Stock. Fluctuations or decreases in the trading price
of the Common Stock may adversely affect the Company's ability to raise
capital through future equity financings.

Anti-takeover Considerations
- ----------------------------
The Board of Directors has the authority, without further action
by the holders of Common Stock, to issue from time to time, up to
5,398,250 additional shares of preferred stock (after giving effect to
the issuance of the Series B Convertible Preferred Stock pursuant to the
Private Placement) in one or more classes or series, and to fix the
rights and preferences of such preferred stock. The Company is subject
to provisions of Delaware corporate law which, subject to certain
exceptions, will prohibit the Company from engaging in any "business
combination" with a person who, together with affiliates and associates,
owns 15% or more of the Company's Common Stock (an "Interested
Stockholder") for a period of three years following the date that such
person became an Interested Stockholder, unless the business combination
is approved in a prescribed manner. These provisions of the Company's
Certificate of Incorporation and of Delaware law may have the effect of
delaying, deterring or preventing a change in control of the Company,
may discourage bids for the Common Stock at a premium over market price
and may adversely affect the market price, and the voting and other
rights of the holders, of the Common Stock.

No Dividends
- ------------
The Company has never paid any cash dividends on the Common Stock
and anticipates that, for the foreseeable future, it will continue to
retain any earnings for use in the operation of its business and does
not intend to pay dividends on the Common Stock. Further, the payment
of dividends on the Common Stock will be subordinate to the rights of
the holders of the Company's outstanding Series B Convertible Preferred
Stock (the "Series B Preferred Stock") to receive payment of any unpaid
and accrued dividends.

BUSINESS OF THE COMPANY
-----------------------

CYTOGEN licenses, discovers and develops site-specific
biopharmaceutical products for the treatment and diagnosis of cancer and
other diseases. The Company's product Quadramet has been approved by
the FDA and is marketed for the treatment of bone pain arising from the
spread of cancer to the bone ("bone metastasis"). The Company's product
ProstaScint has been approved and is marketed as a diagnostic imaging
agent for prostate cancer. In addition, the Company has completed Phase
III clinical trials for ALT for the treatment of metastatic renal cell
carcinoma (kidney cancer that has spread to other parts of the body) and
expects to file a BLA during 1998. The Company has formed a
collaborative arrangement with Elan pursuant to which the parties intend
to focus on the rapid, cost-efficient identification and development of
therapeutic and supportive care products for patients with cancer.
CYTOGEN is also conducting research and development relating to the use
of its proprietary GDL technology, a peptide research and development
program with broad potential applications in drug delivery and drug
discovery.

<PAGE>

Quadramet received FDA approval in March 1997 for relief of bone
pain in patients with confirmed osteoblastic bone lesions that image on
conventional bone scan. Quadramet is licensed in North America and
Latin America on an exclusive basis from Dow Chemical ("Dow").
Historically, treatments for such severe bone pain have included
external beam radiation therapy, narcotic analgesics and other
radiopharmaceuticals. The Company believes that Quadramet will be
competitive with these alternatives based on its safety, efficacy and
ease of administration. The Company intends to expand the use of
Quadramet within the currently approved indication and to perform
clinical trials and seek regulatory approval to extend its use to new
indications such as high-dose therapy for cancer patients, and for use
in refractory rheumatoid arthritis patients. The Company has entered
into an exclusive agreement with DuPont Merck for the manufacture and
marketing of Quadramet in North, South and Central America. CYTOGEN
currently receives royalty revenue from DuPont Merck based on a
percentage of sales of Quadramet or guaranteed minimum payments,
whichever is greater.

ProstaScint has been approved by the FDA for use in identification
of prostate cancer metastases for both newly diagnosed patients at high
risk of metastases and for patients with suspected disease recurrence
following the failure of initial therapy. In order to ensure appropriate
acquisition and interpretation of ProstaScint images, the FDA approval
for ProstaScint requires medical imaging community members to
successfully complete the Company's PIE training and certification
program. Further, to facilitate market acceptance of ProstaScint with
urologists, the Company has entered into a co-promotion agreement with
BARD.

ALT is a proprietary cellular therapy under development by Cellcor,
Inc. ("Cellcor"), a subsidiary of the Company, for the treatment of
mRCC, a life threatening kidney cancer for which adequate therapies do
not exist. Cellcor has completed pivotal Phase III clinical trials of
ALT in mRCC patients and intends to file a BLA during 1998. Targon, a
majority-owned subsidiary of CYTOGEN, was created in September 1996 by
CYTOGEN and Elan. The two companies jointly manage Targon to leverage
certain of their core competencies. Targon draws upon Elan's expertise
in drug delivery and enhanced formulation and CYTOGEN's strength in the
development and registration of cancer products. Targon has entered
into an agreement with Duke University under which Targon will provide
up to $3.75 million over a three year period to support research and
testing with respect to anti-cancer drugs. In exchange, Targon will
receive an option to license products from funded programs and a right
to first review as to licenses for certain other inventions in the field
of cancer during the three year term of the agreement. Funding for
contributions during 1998 will be made from Targon's restricted cash
reserve, and are not expected to have any impact on Cytogen's capital
needs or liquidity during 1998. Although the Company believes that
Targon can meet its funding commitments in the period following 1998
from revenues from ongoing operations and other sources, there can be
no assurance that Targon will, in fact, be able to do so. The Company
believes that this agreement provides a potential source of new products
from one of the nation's leading cancer centers.

CYTOGEN's GDL program consists of research on long peptides that
fold to form complex three-dimensional structures, some of which mimic
important biological structures, and may therefore mediate important
biological functions. A peptide is a small protein or a piece of a
protein, which is made up of a chain of amino acids. Proteins make up
cells, cellular structures and living matter. Proteins have a variety
of functions important to life processes and physiology, including
disease. Synthetic peptides are made by laboratory procedures that
assemble amino acids in sequences, which may or may not occur naturally.
Synthetic peptides can be used to decipher and manipulate the chemical
communication that occurs at the molecular level in cells, thereby

<PAGE>

providing the opportunity to understand and develop products or
processes which, for example, may interfere with the disease process.
The Company believes that the ability of these compounds to bind to
predetermined sites may mediate certain therapeutic or diagnostic
effects more effectively than other existing products. The Company has
entered into a number of collaborative arrangements for the research,
development and commercialization of various aspects of this technology.

The Company has not paid cash dividends on its Common Stock. The
Company currently intends to retain earnings for use in the development
and expansion of its business and, therefore, does not anticipate paying
cash dividends on its Common Stock in the future.

USE OF PROCEEDS
---------------

The Company will not receive any of the proceeds from the sale of
Common Stock being offered by this Prospectus.

<PAGE>

SELLING STOCKHOLDERS
--------------------

The following table sets forth certain information regarding the
beneficial ownership of Common Stock by the Selling Stockholders as of
January 5, 1998, and the number of shares of Common Stock covered by
this Prospectus.

Number of Shares of Number of Shares of
Common Stock Beneficially Number of Shares of Common Stock Beneficially
Name and Address Owned Common Stock Offered Owned Following the
Stockholder Prior to the Offering (1) Hereby (2) Offering (3)
- ---------- ------------------------- ---------- ------------

# of Shares % of Class # of Shares % of Class
----------- ---------- ----------- ----------

<S> <C> <C> <C> <C> <C>
Southbrook International Investments, Ltd. 1,981,424 3.53 2,400,000 4.20 0
c/o Trippoak Advisors, Inc.
630 Fifth Avenue, Suite 2000
New York, NY 10111

Westover Investments L.P. 792,569 1.41 960,000 1.68 0
777 Main Street, Suite 2750
Fort Worth, TX 76102

Montrose Investments L.P. 1,188,854 2.12 1,440,000 2.52 0
777 Main Street, Suite 2750
Fort Worth, TX 76102

Heracles Fund 330,237 .59 400,000 .70 0
Bank of Bermuda (Cayman) Limited
P.O. Box 513
3rd Floor, British American Center
Dr. Roy's Drive
Georgetown, Grand Cayman
Cayman Islands, BWI

Themis Partners, L.P. 330,237 .59 400,000 .70 0
c/o Promethean Investment Group L.L.C.
40 West 57th Street, Suite 1520
New York, NY 10019

Brown Simpson Strategic Growth Fund, L.P. 132,095 .24 160,000 .28 0
152 West 57th Street, 40th Floor
New York, NY 10019

Brown Simpson Strategic Growth Fund, Ltd. 198,143 .35 240,000 .42 0
152 West 57th Street, 40th Floor
New York, NY 10019

</TABLE>
--------------------------

<PAGE>

(1) Includes (i) the number of shares of Common Stock issuable upon
conversion of shares of the Company's Series B Convertible
Preferred Stock, assuming conversion at the formula price in effect
on January 5, 1998 (which price will fluctuate from time to time
based on changes in the market price of the Common Stock and
provisions in the formula for determining the conversion price).
The Series B Preferred Stock was issued by the Company to the
Selling Stockholders in December 1997 in a transaction exempt from
the registration requirements of the Securities Act of 1933
pursuant to Regulation D thereunder in December 1997 (the "Private
Placement").

(2) In order to provide for (i) fluctuations in the market price of the
Common Stock, (ii) provisions in the formula for determining the
conversion price of the Series B Preferred Stock provided for in
the terms thereof (see "Description of Series B Convertible
Preferred Stock") and (iii) shares of Common Stock which may be
issued in payment of dividends on the Series B Preferred Stock, the
aggregate number of shares of Common Stock registered hereby
exceeds the aggregate number of such shares issuable upon
conversion of shares of the Series B Preferred Stock at the
conversion price in effect on the date hereof. For each Selling
Stockholder, the number in this column represents (i) such Selling
Stockholder's pro rata portion of the aggregate number of shares
of Common Stock registered hereby. No Selling Stockholder may
acquire more than 4.99% of the Common Stock unless they give the
Company at least 15 days notice of the waiver of such restrictions.

(3) Assumes sale of all shares offered hereby.

PLAN OF DISTRIBUTION
--------------------

The Selling Stockholders may, from time to time, sell all or a
portion of the shares of Common Stock (the "Shares") on the Nasdaq
National Market, in privately negotiated transactions or otherwise, at
fixed prices that may be changed, at market prices prevailing at the
time of sale, at prices related to such market prices or at negotiated
prices. The Shares may be sold by the Selling Stockholders by one or
more of the following methods, without limitation: (a) block trades in
which the broker or dealer so engaged will attempt to sell the Shares
as agent but may position and resell a portion of the block as principal
to facilitate the transaction, (b) purchases by a broker or dealer as
principal and resale by such broker or dealer for its account pursuant
to this Prospectus, (c) an exchange distribution in accordance with the
rules of such exchange, (d) ordinary brokerage transactions and
transactions in which the broker solicits purchasers, (e) privately
negotiated transactions, (f) short sales and (g) a combination of any
such methods of sale. In effecting sales, brokers and dealers engaged
by the Selling Stockholders may arrange for other brokers or dealers to
participate. Brokers or dealers may receive commissions or discounts
from the Selling Stockholders (or, if any such broker-dealer acts as
agent for the purchasers of such shares, from such purchaser) in amounts
to be negotiated which are not expected to exceed those customary in the
types of transactions involved. Broker-dealers may agree with the
Selling Stockholders to sell a specified number of such Shares at a
stipulated price per share, and, to the extent such broker-dealer is
unable to do so acting as agent for a Selling Stockholder, to purchase
as principal any unsold Shares at the price required to fulfill the
broker-dealer commitment to the Selling Stockholders. Broker-dealers
who acquire Shares as principal may thereafter resell such Shares from
time to time in transactions (which may involve block transactions and
sales to and through other broker-dealers, including transactions of the
nature described above) in the over-the-counter market or otherwise at

<PAGE>

prices and on terms then prevailing at the time of sale, at prices then
related to the then-current market price or in negotiated transactions
and, in connection with such resales, may pay to or receive from the
purchasers of such Shares commissions as described above. The Selling
Stockholders may also sell the Shares in accordance with Rule 144 under
the Securities Act, rather than pursuant to this Prospectus.

The Selling Stockholders and any broker-dealers or agents that
participate with the Selling Stockholders in sales of the Shares may be
deemed to be "underwriters" within the meaning of the Securities Act in
connection with such sales. In such event, any commissions received by
such broker-dealers or agents and any profit on the resale of the Shares
purchased by them may be deemed to be underwriting commissions or
discounts under the Securities Act.

From time to time the Selling Stockholders may engage in short
sales, short sales against the box, puts and calls and other
transactions in securities of the Company or derivatives thereof, and
may sell and deliver the Shares in connection therewith or in settlement
of securities loans. If the Selling Stockholders engage in such
transactions, the Conversion Price may be affected. From time to time
the Selling Stockholders may pledge their Shares pursuant to the margin
provision of its customer agreements with their brokers. Upon a default
by the Selling Stockholders, the broker may offer and sell the pledged
Shares from time to time.

The Company is required to pay all fees and expenses incident to
the registration of the Shares, including fees and disbursements (not
to exceed an aggregate of $10,000) of counsel to the Selling
Stockholders. The Company has agreed to indemnify the Selling
Stockholders against certain losses, claims, damages and liabilities,
including liabilities under the Securities Act.

DESCRIPTION OF CAPITAL STOCK
----------------------------

As of the date of this Prospectus, the Company's authorized capital
stock consists of 89,600,000 shares of Common Stock, par value $0.01 per
share, and 5,400,000 shares of preferred stock, $0.01 per share.
Pursuant to the Certificates of Designation for the Series A Preferred
Stock (as defined below) and for the Series B Preferred Stock, 1,000
shares of Series A Preferred Stock and 750 shares of Series B Preferred
Stock, respectively, have been authorized for issuance. The description
below is a summary of all material provisions of the Company's Common
Stock and preferred stock.

Common Stock
- ------------
The holders of Common Stock are entitled to one vote per share on
all matters voted on by the stockholders, including elections of
directors. Except as otherwise required by law or as provided in any
resolutions adopted by the Board with respect to the preferred stock of
the Company, the holders of shares of Common Stock will exclusively
possess all voting power. Subject to the preferential rights, if any,
of holders of any then outstanding preferred stock, the holders of
Common Stock are entitled to receive dividends when, as and if declared
by the Board of Directors of the Company out of funds legally available
therefor. The terms of the Common Stock do not grant to the holders
thereof any preemptive, subscription, redemption, conversion or sinking
fund rights. Subject to the preferential rights of holders of any then
outstanding preferred stock, the holders of Common Stock are entitled
to share ratably in the assets of the Company legally available for

<PAGE>

distribution to stockholders in the event of the liquidation,
dissolution or winding up of the Company.

As of November 6, 1997, 51,169,605 shares of Common Stock were
issued and outstanding, and 1,260,000 shares of Common Stock were
reserved for issuance upon the exercise of certain outstanding warrants
and approximately 6,230,102 shares were reserved for issuance pursuant
to stock option plans and Employee Stock Purchase Plans. The Company
has issued to Dow and Elan, warrants to purchase an aggregate of
1,260,000 shares of Common Stock at prices ranging from $8.40 to $14.00
per share. In connection with the Company's acquisition of an exclusive
license from Dow, CYTOGEN issued to Dow two warrants to purchase an
aggregate of 260,000 shares of Common Stock at $12.50 per share. The
remaining warrant is held by Elan. See "Description of Capital Stock
- --Preferred Stock" for a description of the Elan warrant. In addition,
CYTOGEN has reserved up to 1,785,715 shares of Common Stock issuable in
the event of conversion of the 1,000 shares of Series A Preferred Stock
held by Elan. In the event Elan does not elect conversion but elects
to exchange the Series A Preferred Stock for an interest in Targon, the
Company will eliminate the 1,785,715 reserve. The warrant held by Elan
for 1,000,000 shares of Common stock will then become exercisable. The
warrant is void if Elan elects conversion of its shares of Series A
Preferred Stock into Common Stock.

The Certificate of Incorporation and Bylaws of the Company contain
certain provisions which may have the effect of delaying, deferring, or
preventing a change of control of the Company. See "Risk Factors Anti-takeover
Considerations". In addition, the Board generally has the
authority, without further action by stockholders, to fix the relative
powers, preferences, and rights of the unissued shares of preferred
stock of the Company. Provisions which could discourage an unsolicited
tender offer or takeover proposal, such as extraordinary voting,
dividend, redemption, or conversion rights, could be included in such
preferred stock. For a description of certain rights which may also
affect a change-in-control transaction, see "Description of Capital
Stock--Preferred Stock."

Preferred Stock
- ---------------
Pursuant to the Certificate of Incorporation, the Company has the
authority to issue up to 5,400,000 shares of preferred stock, $0.01 par
value per share, in one or more series as determined by the Board of
Directors of the Company. The Board of Directors of the Company may,
without further action by the stockholders of the Company, issue one or
more series of preferred stock and fix the rights and preferences of
such shares, including the dividend rights, dividend rates, conversion
rights, exchange rights, voting rights, terms of redemption, redemption
price or prices, liquidation preferences and the number of shares
constituting any series or the designation of such series. Shares of
any series of preferred stock of the Company may be represented by
depositary shares evidenced by depositary receipts, each representing
a fractional interest in a share of preferred stock of such series and
deposited with a depository. The use of this mechanism could increase
the number of interests in preferred stock issued by the Company. The
rights of the holders of Common Stock will be subject to, and may be
adversely affected by, the rights of holders of preferred stock issued
by the Company in the future. In addition, the issuance of preferred
stock could have the effect of making it more difficult for a third
party to acquire, or of discouraging a third party from attempting to
acquire, control of the Company.

Series A Preferred Stock
- ------------------------
Pursuant to the Certificate of Designations, Powers, Preferences
and Rights of the Series A Convertible and Exchangeable Preferred Stock
(the "Series A Certificate of Designation"), 1,000 shares of Series A
Preferred Stock (the "Series A Preferred Stock"), with a liquidation
preference of $5,000 per share, have been authorized for issuance. Of
these authorized shares, all have been issued and are outstanding. All
of the 1,000 shares of Series A Preferred Stock were purchased by Elan

<PAGE>

for $15.0 million in September 1996. The proceeds from the sale of the
Series A Preferred Stock, along with $5.0 million in proceeds from the
sale of Common Stock to Elan were used to fund the formation of Targon
Corporation, a majority-owned (99.75%) subsidiary of the Company, and
the acquisition of certain technology from Elan. Targon focuses
exclusively on the rapid development, registration, manufacturing and
commercialization of oncology products.

The Series A Preferred Stock held by Elan may, at Elan's option be
either (i) exchanged for a portion of the Company's interest in Targon
which declines from 50% to 35%, depending on the time of the exchange,
which exchange may not occur later than September 30, 2001 or (ii)
converted into shares of Common Stock of CYTOGEN. If Elan elects to
exchange the Series A Preferred Stock for a portion of the Company's
interest in Targon, then Elan will be entitled through March 31, 2003
to exercise a warrant to purchase up to 1 million shares of CYTOGEN
Common Stock, at an exercise price per share which escalates from $8.40
to $14 over the life of the warrant. If Elan elects to convert the
Series A Preferred Stock into CYTOGEN Common Stock, it will receive a
number of shares which declines from 1,785,715 shares to 1,071,429
shares, depending on the time of conversion. If Elan exercises its
conversion right, then the Company will retain its ownership interest
in Targon. Elan must elect to exchange its Series A Preferred Stock no
later than September 30, 2001. Any shares of Series A Preferred Stock
not exchanged or converted by March 31, 2003 will be automatically
converted into CYTOGEN Common Stock on that date.

The Series A Preferred Stock has no special dividend rights,
however, if dividends are declared on the CYTOGEN Common Stock, the
holders of Series A Preferred Stock will be entitled to such dividends
as they would have received had they converted their shares of Series
A Preferred Stock into Common Stock immediately prior to the dividend.
The Series A Preferred Stock has no voting rights with respect to
general corporate matters, except as provided by law or as set forth in
the Series A Certificate of Designation. The Series A Certificate of
Designation provides that the Company will not amend or repeal any
provision of, or add any provision to, the Certificate of Incorporation
or the Bylaws if such action would adversely affect the preferences,
rights, privileges or powers of the Series A Preferred Stock, or
increase or decrease the number of authorized shares of Series A
Preferred Stock, without the consent of 50% of the holders of the
outstanding shares of the Series A Preferred Stock.

Description of Series B Convertible Preferred Stock
- ---------------------------------------------------
The 750 outstanding shares of Series B Preferred Stock were issued
by the Company to the holders of Series B Preferred Stock (the "Series
B Holders") in the Private Placement. Each share of Series B Preferred
Stock has a par value of $.01 per share and a stated value of $10,000
per share (the "Stated Value").

Pursuant to the Certificate of Designation relating to the Series
B Preferred Stock (the "Series B Certificate of Designation") the
Series B Holders are entitled to receive, when, as and if declared by
the Board of Directors of the Company (the "Board of Directors"), out
of funds legally available therefor, cumulative dividends at a rate of
6% of the Stated Value per share per annum, payable, at the option of
the Company, in cash or shares of Common Stock (subject to certain
limitations). Dividends on the Series B Preferred Stock shall be deemed
to accrue from the date of original issue of the Series B Preferred
Stock, whether or not earned or declared and whether or not there are
profits, surplus or other funds of the Company legally available for the
payment of dividends. Accrued dividends on the Series B Preferred Stock
shall be paid on the date such Series B Preferred Stock is converted,
but the Company shall have the option to pay dividends in cash or shares

<PAGE>

of Common Stock and more frequently as and when declared by the Board
of Directors. The Series B Certificate of Designation does not provide
for a sinking fund.

The Series B Certificate of Designation prohibits the repurchase
by the Company of, or the payment or declaration of any dividends with
respect to, any securities of the Company junior to or pari passu with
the Series B Preferred Stock (with certain exceptions).

Except as may be required by law and except with respect to certain
actions which may adversely affect the Series B Holders, the Series B
Holders are not entitled to vote on any matter submitted to a vote of
stockholders of the Company.

The Series B Preferred Stock ranks senior with respect to rights
on liquidation, winding-up and dissolution of the Company to the
Company's Common Stock. Upon any voluntary or involuntary liquidation,
dissolution or winding-up of the Company, holders of Series B Preferred
Stock will be entitled to receive $10,000 per share, plus accrued and
unpaid dividends, before any distribution is made on the common stock
or any preferred stock of the Company ranking junior as to liquidation
rights to the Series B Preferred Stock.

The Series B Holders have the right to convert shares of Series
B Preferred Stock into common stock at a conversion price (the "Initial
Conversion Price") equal to the lesser of (a) $3.4575 and (b) at a
discount of up to 85% of the average of four closing bid prices chosen
by the Series B Holders during the twenty-five trading days prior to
notice of conversion, which discount is initially 95% and shall increase
by 5% on the first day of the two months subsequent to the Original
Issue Date of the Series B Preferred Stock. If, however, the average
per share market value for the five day trading period immediately
preceding the conversion date exceeds the Initial Conversion Price by
180%, then the conversion price otherwise applicable to such conversion
shall be increased by an amount equal to 50% of the difference between
the average per share market value for the five day trading period
immediately preceding the conversion date and the Initial Conversion
Price.

The Conversion Price may be adjusted under certain circumstances,
including the failure by the Company to file a registration statement
with the Securities and Exchange Commission (the "Commission") for the
underlying shares into which the Series B Preferred Stock is
convertible, the failure of such registration statement to be declared
effective by the Commission within certain time periods, suspension of
trading of the Company's common stock or upon the occurrence of certain
other events. If on the date of conversion, the conversion price then
in effect would result in the number of shares issuable in connection
with such conversion (including the conversion shares issued in respect
of payment of dividends) equalling or exceeding 20% of the number of
shares of Common Stock outstanding on the Original Issue Date, the
Company is, under certain circumstances, required to obtain the approval
of a majority of shareholders to authorize such issuance. If such
approval is not obtained certain penalties may apply. The Series B
Holders have agreed that in no event shall any such Series B Holder be
entitled to convert any shares of Series B Preferred Stock if the
issuance of shares of Common Stock upon a proposed conversion, when the
shares to be so issued are counted together with other shares of common
stock beneficially owned by such Series B Holder would result in a
Series B Holder beneficially owning more than 4.999% of the outstanding
shares of Common Stock.

The Series B Preferred Stock is convertible at the option of the
Company three years from the Original Issue Date. All outstanding and
unconverted shares of Series B Preferred Stock are redeemable on the

<PAGE>

third anniversary of the Original Issue Date at a price per share equal
to the product of (1) the average per share market value for the five
trading days immediately preceding (i) the third anniversary of the
original issue date or (ii) the date of payment in full by the Company
of the redemption price, whichever is greater, and (2) the Stated Value
plus accrued but unpaid dividends not paid in Common Stock divided by
the Conversion Price for the Series B Preferred Stock calculated on the
third anniversary of the Original Issue Date.

Transfer Agent and Registrar
- ----------------------------
Chase Mellon Shareholder Services, L.L.C. is the transfer agent and
registrar for the Common Stock.

LEGAL OPINIONS
--------------

The validity of the shares of Common Stock to which this Prospectus
relates has been passed upon for the Company by Dewey Ballantine LLP,
New York, New York.

EXPERTS
-------

The financial statements of CYTOGEN incorporated by reference in
this Prospectus and elsewhere in the Registration Statement, to the
extent and for the periods indicated in their report, have been audited
by Arthur Andersen LLP, independent public accountants, as indicated in
their report with respect thereto, and are incorporated by reference
herein in reliance upon the authority of said firm as experts in giving
said report.

<PAGE>

No dealer, salesman or other
person has been authorized to give any
information or to make representations
other than those contained in
this Prospectus, and, if given or 6,000,000 Shares
made, such information or representa-
tions must not be relied upon as having CYTOGEN Corporation
been authorized by the Company or the
Selling Stockholders. Neither the Common Stock
delivery of this Prospectus nor any
sale made hereunder shall, under any
circumstances, create an implication
that the information herein is correct
as of any time subsequent to its date. __________
This Prospectus does not constitute an
offer or solicitation by anyone in any PROSPECTUS
jurisdiction in which such offer __________
or solicitation is not authorized or in
which the person making such offer or
solicitation is not qualified to do so
or to anyone to whom it is unlawful to
make such offer or solicitation.

TABLE OF CONTENTS Page
Available Information . . . . . . . . . . . . . . . . . . . . . 4
Information Incorporated
by Reference. . . . . . . . . . . . . . . . . . . . . . . . . 5
Risk Factors. . . . . . . . . . . . . . . . . . . . . . . . . . 5
Business of the Company . . . . . . . . . . . . . . . . . . . . 16
Use of Proceeds . . . . . . . . . . . . . . . . . . . . . . . . 18
Selling Stockholders. . . . . . . . . . . . . . . . . . . . . . 19
Plan of Distribution. . . . . . . . . . . . . . . . . . . . . . 20
Description of Capital Stock. . . . . . . . . . . . . . . . . . 21
Description of Series A
Convertible Preferred Stock . . . . . . . . . . . . . . . . . 22
Description of Series B
Convertible Preferred Stock . . . . . . . . . . . . . . . . . 23

Legal Opinions. . . . . . . . . . . . . . . . . . . . . . . . . 25
Experts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
February , 1998

<PAGE>

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS
--------------------------------------

Item 14. Other Expenses of Issuance and Distribution

The estimated expenses in connection with this offering are as follows:

Amount
to be Paid

SEC registration fee $ 1,884
Nasdaq registration fee 17,500
Legal fees and expenses (including
Blue Sky fees and expenses) 25,000
Accounting fees and expenses 2,000
Miscellaneous 3,616
----------
Total $50,000

Item 15. Indemnification of Directors and Officers

The Delaware General Corporation Law (the "DGCL") provides for
indemnification of directors, officers, employees and agents, subject
to certain limitations (Delaware Code, Title 8 Section 145). Article VII
of the Company's By-laws provides that expenses incurred by an officer
or director of the Company in defending a civil or criminal action, suit
or proceeding shall be paid by the Company in advance of a final
disposition of the action, suit or proceeding upon receipt by the
Company of an undertaking by the officer or director that he or she will
repay such expenses if it is ultimately determined that he or she is not
entitled to indemnification under the DGCL.

As permitted by Section 102 of the DGCL, the Company's Certificate
of Incorporation contains provisions eliminating a director's personal
liability for monetary damages to the Company and its stockholders
arising from a breach of a director's fiduciary duty except for
liability under Section 174 of the DGCL or liability for any breach of
the director's duty of loyalty to the Company or its stockholders, for
acts or omissions not in good faith or which involve intentional
misconduct or a knowing violation of law or for any transaction by which
the director derived an improper personal benefit. The Company has also
entered into indemnification agreements with its directors and officers
providing for indemnification and advancements of expenses to the
fullest extent permitted under Delaware law.

<PAGE>

Item 16. Exhibits and Financial Statement Schedules

No.
- ---

4.1 Certificate of Designation of 6% Convertible Preferred Stock,
Series B (1)

5.1 Opinion of Dewey Ballantine LLP.

10.1 Convertible Preferred Stock Purchase Agreement by and between
Cytogen Corporation and Southbrook International Investments, Ltd.,
Westover Investments, L.P., Montrose Investments, L.P., Heracles
Fund, Themis Partners, L.P., and Brown Simpson Strategic Growth
Fund, Ltd. (1)

10.2 Registration Rights Agreement by and between Cytogen Corporation
and Southbrook International Investments, Ltd., Westover
Investments, L.P., Montrose Investments, L.P., Heracles Fund,
Themis Partners, L.P., and Brown Simpson Strategic Growth Fund,
Ltd. (1)

23.1 Consent of Arthur Andersen LLP.

23.2 Consent of Dewey Ballantine LLP (included in Exhibit 5.1)

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

(1) Incorporated by reference to the Company's current report on Form
8-K filed on December 22, 1997.

Item 17. Undertakings

The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being
made, a post-effective amendment to this registration statement:

(i) To include any prospectus required by Section 10(a)(3)
of the Securities Act of 1933;

(ii) To reflect in the prospectus any facts or events
arising after the effective date of the registration
statement (or the most recent post-effective amendment
thereof) which, individually or in the aggregate, represent
a fundamental change in the information set forth in the
registration statement;

(iii) To include any material information with respect to the
plan of distribution not previously disclosed in the
registration statement or any material change to such
information in the registration statement;

<PAGE>

Provided, however, that paragraphs (1)(i) and (1)(ii) do not
apply if the registration statement is on Form S-3 or Form S-8,
and the information required to be included in the post-effective
amendment by those paragraphs is contained in periodic
reports filed by the registrant pursuant to Section 13 or
Section 15(d) of the Securities Exchange Act of 1934 that are
incorporated by reference in the registration statement.

(2) That, for the purpose of determining any liability under the
Securities Act of 1933, each post-effective amendment shall be
deemed to be a new registration statement relating to the
securities offered herein, and the offering of such securities
at that time shall be deemed to be the initial bona fide
offering thereof.

(3) To remove from registration by means of a post-effective
amendment any of the securities being registered which remain
unsold at the termination of the offering.

The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing
of the registrant's annual report pursuant to Section 13(a) or Section
15(d) of the Securities Exchange Act of 1934 that is incorporated by
reference in the registration statement shall be deemed to be a new
registration statement relating to the securities offered herein, and
the offering of such securities at that time shall be deemed to be the
initial bona fide offering thereof.

Insofar as indemnification for liabilities arising under the
Securities Act of 1933 may be permitted to directors, officers and
controlling persons of the registrant pursuant to the foregoing
provisions, or otherwise, the registrant has been advised that in the
opinion of the Securities and Exchange Commission such indemnification
is against public policy as expressed in the Securities Act of 1933 and
is, therefore, unenforceable. In the event that a claim for
indemnification against such liabilities (other than the payment by the
registrant of expenses incurred or paid by a director, officer or
controlling person of the registrant in the successful defense of any
action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered,
the registrant will, unless in the opinion of counsel the matter has
been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by it is against
public policy as expressed in the Securities Act of 1933 and will be
governed by the final adjudication of such issue.

The undersigned registrant hereby undertakes to deliver or cause
to be delivered with the prospectus, to each person to whom the
prospectus is sent or given, the latest annual report to security
holders that is incorporated by reference in the prospectus and
furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule
14c-3 under the Securities Exchange Act of 1934; and, where interim
financial information required to be presented by Article 3 of
Regulation S-X is not set forth in the prospectus, to deliver, or cause
to be delivered to each person to whom the prospectus is sent or given,
the latest quarterly report that is specifically incorporated by
reference in the pospectus to provide such interim financial
information.

<PAGE>

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the
registrant certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-3 and has duly caused
this Amendment No. 1 to registration statement to be signed on its
behalf by the undersigned, thereunto duly authorized, in the City of
Princeton, State of New Jersey, on February 26, 1998.

CYTOGEN CORPORATION

By: /s/ John E. Bagalay, Jr.

Name: John E. Bagalay, Jr.
President and Chief
Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this
Amendment No. 1 to Registration Statement has been signed below by the
following persons on behalf of the registrant and in the capacities and
on the dates indicated.

Signature Title Date
- --------- ----- ----
<C> <C> <C>
s/ * Chairman of the Board February 26, 1998
- ------------------------
William C. Mills III

/s/ John E. Bagalay, Jr. President and Chief Executive Officer,
- ------------------------ Chief Financial Officer and Director February 26, 1998
John E. Bagalay, Jr.

/s/ Jane M. Maida Chief Accounting Officer February 26, 1998
- ------------------------
Jane M. Maida

/s/ * Director February 26, 1998
- ------------------------
Charles E. Austin

/s/ * Director February 26, 1998
- ------------------------
Ronald J. Brenner

/s/ * Director February 26, 1998
- ------------------------
James A. Grigsby

/s/ * Director February 26, 1998
- ------------------------
Robert F. Hendrickson

/s/ * Director February 26, 1998
- ------------------------
Thomas J. McKearn

/s/ * Director February 26, 1998
- -------------------------
Donald E. O'Neill

<PAGE>

* /s/ Donald F. Crane, Jr.
- ---------------------------
Attorney-in-fact

<PAGE>

EXHIBIT INDEX
- -------------

Exhibit
Number Description Page #
- ------ ----------- ------
5.1 Opinion of Dewey Ballantine LLP 33

23.1 Consent of Arthur Andersen LLP 34

23.2 Consent of Dewey Ballantine LLP (included in Exhibit 5.1) 33

24.1 Power of Attorney (included on the signature page hereto) 30

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

</TABLE>

Exhibit 5.1
-----------

January 6, 1998

Cytogen Corporation
600 College Road East
Princeton, New Jersey 08540

Ladies and Gentlemen:

We have acted as counsel to Cytogen Corporation, a
Delaware corporation (the "Company"), in connection with the
preparation and filing by the Company of a Registration
Statement on Form S-3 (the "Registration Statement") under the
Securities Act of 1933, as amended (the "Act"), for the
registration of 6,000,000 shares of common stock, $.01 par
value per share (the "Common Stock"), of the Company which may
be issued upon the conversion of the Company's 6% Convertible
Preferred Stock, Series B (the "Series B Preferred Stock"),
plus such additional indeterminate number of shares of Common
Stock as may become issuable either as a result of the
anti-dilution provisions of the Certificate of Designation
of the Series B Preferred Stock (the "Certificate
of Designation")pursuant to which the Common Stock will
be issued, or by reason of a reduction in the conversion price
of the Series B Preferred Stock in accordance with the provisions
of the Certificate of Designation.

We have examined and are familiar with originals or
copies, certified or otherwise identified to our satisfaction,
of such documents, corporate records, certificates of public
officials and officers of the Company and such other
instruments as we have deemed necessary or appropriate as a
basis for the opinions expressed below, including the
Registration Statement, the Restated Certificate of
Incorporation of the Company and the By-laws of the Company.

Based on the foregoing, we are of the opinion that
the Common Stock issuable upon conversion of the Series B
Preferred Stock (including those shares of Series B Preferred
Stock issued as dividends, if any) has been duly authorized and
reserved for issuance and, when duly issued and delivered upon
conversion of the Series B Preferred Stock in accordance with
the terms of the Convertible Preferred Stock Purchase Agreement
dated December 9, 1997 and the Certificate of Designation, will
be validly issued, fully paid and nonassessable.

We hereby consent to the filing of this opinion as
Exhibit 5.1 to the Registration Statement. In giving such
consent, we do not thereby admit that we come within the
category of persons whose consent is required under Section 7
of the Act or the rules and regulations of the Securities and
Exchange Commission thereunder.

We express no opinion as to the laws of any
jurisdiction other than the laws of the State of New York, the
general corporate laws of the State of Delaware and the federal
law of the United States of America. The foregoing opinion is
rendered as of the date hereof, and we assume no obligation to
update such opinion to reflect any facts or circumstances which
may hereafter come to our attention or any changes in the law
which may hereafter occur.

Very truly yours,

/s/ DEWEY BALLANTINE LLP

DEWEY BALLANTINE LLP

EXHIBIT 23.1
------------

CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS

As independent public accountants, we hereby consent to the
incorporation by reference in this Form S-3 Registration
Statement of our report dated January 24, 1997 included in
CYTOGEN Corporation's Form 10-K for the year ended December 31,
1996, and to all references to our Firm included in this
Registration Statement.

ARTHUR ANDERSEN LLP

Philadelphia, PA
January 6, 1998