COMMONWEALTH OF MASSACHUSETTS

SUFFOLK, SS.                                   SUPERIOR COURT DEPARTMENT
                                               BUSINESS LITIGATION SESSION
- ------------------------------------
                                    )
CYTOGEN CORPORATION,                )
                                    )
                   Plaintiff,       )
                                    )          CIVIL ACTION NO. 06-0313
v.                                  )
                                    )
 ADVANCED MAGNETICS, INC.           )
                                    )
                   Defendant.       )
- ------------------------------------)



                            COMPLAINT AND JURY DEMAND
                            -------------------------


     Plaintiff Cytogen  Corporation  ("Cytogen"),  for its complaint against the
defendant Advanced Magnetics,  Inc. ("AVM"), alleges as follows:

     1.  Cytogen is a Delaware corporation  with its principal place of business
in  Princeton,  New  Jersey.  Cytogen is a  biopharmaceutical  company  engaged,
primarily,  in the business of developing and  commercializing  oncology-focused
pharmaceutical compounds.

     2.  AVM is a Delaware corporation  with its principal  place of business in
Cambridge,   Massachusetts.  AVM  is  engaged  in  the  business  of  developing
microscopic  iron oxide particles  ("nanoparticles")  for use in  pharmaceutical
products.  Its resident  agent is CT  Corporation  System,  101 Federal  Street,
Boston, Massachusetts 02110.

     3.  Venue is  proper in  the  Business Litigation  Session of  the Superior
Court because this case involves a complex  business dispute and AVM's principal
place of business is located approximately six miles from this Court in a county
under the reach of the Business Litigation Session.





                                      FACTS
                                      -----

     4.  On or about  December 21, 1999,  AVM  submitted a new drug  application
("NDA")  to the United  States  Food and Drug  Administration  ("FDA") to obtain
approval  for the  marketing  and  sale of a  pharmaceutical  compound  known as
Combidex.  Combidex is an  investigational  functional  molecular  imaging agent
consisting of iron oxide  nanoparticles,  which is being  developed to assist in
the  detection  of  cancerous  lymph nodes by aiding in the  differentiation  of
cancerous from  non-cancerous  lymph nodes during the magnetic resonance imaging
(also known as MRI) process.

     5.  In or  about  June  2000, the  FDA  issued  an  approvable  letter  for
Combidex,  indicating  that Combidex could be approved for sale and marketing if
AVM followed certain  instructions and met certain  conditions  contained in the
letter. The approvable letter,  among other things,  directed AVM to conduct and
submit  to the FDA at least  one  additional  robust  study in an  appropriately
defined clinical setting in order to obtain regulatory approval.

     6.  On or about August 25, 2000, AVM and Cytogen entered into a License and
Marketing  Agreement (the  "Agreement"),  pursuant to which AVM granted  Cytogen
"the exclusive right and license to distribute,  market,  offer to sell and sell
Combidex" for all  applications  in the  territorial  United States.  A true and
correct  copy of the  Agreement  is attached to this  Complaint.  The  Agreement
provided  the same  rights  and  license  for  another  pharmaceutical  compound
referred to as Code 7228 (now known as  ferumoxytol)  in the field of diagnostic
imaging for oncology. In exchange,  Cytogen provided AVM with a specified number
of shares of Cytogen  common stock valued at  approximately  $13,000,000  on the
date of payment and agreed to pay AVM a royalty on future sales of Combidex once
the FDA approved Combidex for sale.


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     7.  Pursuant to the  Agreement, AVM is required to  perform all of the work
and bear all of the out-of-pocket costs necessary to obtain FDA approval for the
commercial  marketing and sale of Combidex in the United  States,  including all
studies,  human clinical trials and other work upon which the FDA's approval was
conditioned.

     8.  During  the negotiation  of  the  Agreement,   AVM   also  specifically
represented  that  it  would  meet  the  requirements  of the  FDA's  June  2000
approvable  letter and undertake the necessary  steps to obtain FDA approval for
Cytogen  to  market  and  sell  Combidex  in  the  United  States.  Since  those
negotiations, AVM has maintained and repeated those representations.

     9.  The Agreement  will  expire in  August  2010,  unless  renewed  by  the
parties.

     10. Under  Paragraph 13 of the Agreement, both parties  promised to "comply
with all laws and regulations  applicable to such rights and obligations  [under
the Agreement]."

     11. Although  AVM  made  certain  attempts  to respond to the  requirements
contained  in the  FDA's  June  2000  approvable  letter,  AVM did not  submit a
response to the FDA's June 2000  approvable  letter  until  September  2004.  In
addition,  AVM's response did not contain  information  and data required by the
FDA,  including an additional robust study in an appropriately  defined clinical
setting as required by the FDA's June 2000 approvable letter.

     12. On March 3, 2005, the FDA's Oncologic Drugs Advisory Committee ("ODAC")
voted to not recommend approval of the proposed indication for Combidex.

     13. The ODAC also  informed  AVM that it wanted AVM to "come back with more
data."

     14. Then, on or about March 24, 2005, the FDA sent AVM a second  approvable
letter,  again indicating that before AVM's application  could be approved,  AVM
would  be  required  to  address  several  specific   clinical  and  statistical
deficiencies.  Among other


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instructions,  the approvable  letter  directed AVM to "provide  additional data
from adequate and well-controlled  clinical investigations" that demonstrate the
efficacy of Combidex.

     15. Notwithstanding the  specific instructions contained in the FDA's March
2005  approvable  letter,  AVM  has  not  undertaken   additional  adequate  and
well-controlled  clinical investigations for Combidex and has publicly announced
that it has no current intention to do so.

     16. AVM has also failed to commit adequate  staff,  resources and expertise
and to take  other  reasonable  steps  necessary  to  satisfy  the  requirements
contained in the FDA's March 2005  approvable  letter and to obtain FDA approval
of Combidex.

     17. Without additional adequate and well-controlled clinical investigations
and the  additional  data and  information  requested  in the FDA's  March  2005
approvable  letter,  AVM cannot  meet the  requirements  of the FDA's March 2005
approvable  letter or obtain FDA approval for the marketing and sale of Combidex
in the United States.

     18. Rather  than  perform   the  adequate  and   well-controlled   clinical
investigations  requested by the FDA or take other reasonable steps necessary to
obtain timely FDA approval of Combidex, AVM has devoted substantial resources to
the rapid development of another AVM product,  ferumoxytol (formerly Code 7228),
in a field in which AVM was  unwilling  to permit  Cytogen to market or sell the
product.

     19. In  contrast,  AVM has  failed to take  reasonable  steps to obtain FDA
approval for Combidex. In fact, on or about December 15, 2005, Jerome Goldstein,
AVM's Chief  Executive  Officer,  informed  Cytogen of his belief that:  (i) AVM
would not obtain  FDA  approval  for  Combidex  for a number of years;  (ii) the
Agreement would expire shortly after such approval; (iii) because there would be
only a short time for  Cytogen to market  Combidex,  Cytogen  could not  justify
making the investment necessary to fulfill its obligation under the Agreement to


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market and sell Combidex; and (iv) AVM would claim a default under the Agreement
and seek to  terminate  the  license  if  Cytogen  did not  make the  investment
necessary  to fulfill  its  obligation  under the  Agreement  to market and sell
Combidex.  Mr.  Goldstein's  beliefs,  if true,  would  deprive  Cytogen  of the
opportunity  to  realize  any  financial  gain  from  the  marketing  or sale of
Combidex.  Mr. Goldstein urged Cytogen to simply relinquish its rights under the
Agreement.

     20. On or about November 2004, AVM unilaterally rejected Cytogen's proposal
made under Section 2 of the Agreement to conduct additional clinical studies for
Combidex,  including:  (i)  clinical  outcomes  studies  required to support the
commercial  introduction of Combidex for lymph node imaging;  (ii)  non-oncology
imaging applications,  such as those being pursued by AVM's European partner for
Combidex; and (iii) a potential therapeutic indication for Combidex.

     21. AVM has continued to invest in  ferumoxytol  (formerly Code 7228) for a
therapeutic  indication  outside of the field of use licensed to Cytogen  (e.g.,
diagnostic  imaging  applications  in oncology) and has not  initiated  clinical
studies of  ferumoxytol  (formerly  Code 7228) in oncology  imaging  despite the
protracted regulatory process for Combidex.

                                CAUSES OF ACTION
                                ----------------

                                     COUNT I
                                     -------
                               BREACH OF CONTRACT

     22. Cytogen repeats and incorporates by reference the allegations contained
in  Paragraphs  1 through  21 above as  though  fully  stated  herein.

     23. The Agreement constitutes a contract.

     24. AVM has  breached the terms of the  Agreement by failing to  reasonably
pursue FDA approval  for the  commercial  marketing  and sale of Combidex in the
United  States,  including,  but not  limited  to,  AVM's  failure to follow the
instructions and satisfy the conditions


                                       5



set forth in the FDA's June 2000 and March  2005  approvable  letters  and AVM's
failure to commit  adequate  resources and otherwise  take  reasonable  steps to
obtain FDA approval of Combidex.

     25. As  a direct  and  proximate  result  of AVM's  breaches,  Cytogen  has
suffered damages.

                                    COUNT II
                                    --------
                BREACH OF COVENANT OF GOOD FAITH AND FAIR DEALING

     26. Cytogen repeats and incorporates by reference the allegations contained
in Paragraphs 1 through 25 above as though fully stated herein.

     27. The Agreement  carried with it implied covenants of good faith and fair
dealing  running  from  AVM to  Cytogen.  The  conduct  of AVM  described  above
constitutes a breach of the implied covenant of good faith and fair dealing.

     28. AVM breached the covenant of good faith and fair dealing implied in the
Agreement  by  failing  to  provide  information  and  data  from  adequate  and
well-controlled  clinical  investigations,  as  directed  by the  FDA.

     29. AVM  breached the covenant of good faith and fair dealing by failing to
commit and maintain  adequate  resources and  expertise  and to take  reasonable
steps necessary to timely secure FDA approval of Combidex.

     30. AVM's  failure  to  reasonably  pursue  FDA   approval  while  devoting
substantial  resources to the  development of another  product and attempting to
obtain a waiver of Cytogen's rights under the Agreement  constitutes a breach of
the covenant of good faith and fair dealing  implied in the Agreement.

     31. As a result of AVM's  breach of the implied  covenant of good faith and
fair dealing, Cytogen has suffered damages.


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                                   COUNT III
                                   ---------
                          FRAUDULENT MISREPRESENTATION

     32. Cytogen repeats and incorporates by reference the allegations contained
in Paragraphs 1 through 31 above as though fully stated herein.

     33. AVM  represented,   and   has  maintained,   that  it  would  meet  the
requirements of the FDA's approvable letters and take reasonable steps to secure
timely FDA approval for  Combidex.

     34. These representations were material to Cytogen's decision to enter into
the Agreement and to its continued performance under the Agreement.

     35. AVM knew or  reasonably  should  have known that these  representations
were false.

     36. Cytogen relied on these  representations  to its detriment and has been
damaged as a result.

                                    COUNT IV
                                    --------
                                UNJUST ENRICHMENT

     37. Cytogen repeats and incorporates by reference the allegations contained
in Paragraphs 1 through 36 above as though fully stated herein.

     38. Because  AVM has not taken  reasonable  steps to secure FDA approval of
Combidex as it agreed,  the  compound has not been  approved and Cytogen  cannot
market it.

     39. Cytogen  provided  AVM  with  shares  of its  common  stock,  valued at
approximately  $13,000,000  on the  date of  payment,  in  consideration  of the
Agreement and in exchange for the exclusive right to market Combidex.


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     40. AVM has not returned the common stock and has been unjustly enriched as
a result.

                                     COUNT V
                                     -------
                            VIOLATION OF G.L. C. 93A

     41. Cytogen repeats and incorporates by reference the allegations contained
in Paragraphs 1 through 40 above as though fully stated herein,

     42. At all relevant times,  AVM was engaged in trade or commerce within the
Commonwealth of Massachusetts.

     43. AVM knew, or reasonably  should have known,  that its actions would not
be adequate to secure timely FDA approval to market and sell Combidex.


     44. The acts of AVM set forth  above,  including,  but not  limited to, its
failure to meet the  requirements  of the  approvable  letters and to take other
reasonable steps to secure FDA approval,  despite its promises,  representations
and  affirmations  that it would do so, are unfair and deceptive acts under G.L.
c. 93A ss.ss. 2, 11.

     45. AVM's  violations  of G.L.  c. 93A   described  herein  were  performed
willfully and knowingly.

     46. As a result of AVM's unfair and deceptive acts,  Cytogen has suffered a
loss of money and property.

                                RELIEF REQUESTED
                                ----------------

     WHEREFORE,  Cytogen respectfully requests that this Court enter judgment in
its favor on all Counts of the Complaint and grant the following relief:

     1.  Under Counts I through IV, award compensatory and exemplary  damages in
an amount to be determined at trial;


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     2.  Under Count V, find that AVM has committed  willful violations of Mass.
Gen. L. ch. 93A ss.ss.  2, 11 and award Cytogen  treble  damages and  attorneys'
fees;

     3.  Order specific performance in the form of an order that requires AVM to
comply  with the  directions  of the June  2000 and  March  2005 FDA  approvable
letters,  and directs AVM to take all reasonable steps to secure FDA approval of
Combidex;

     4.  Award  Cytogen  their  reasonable  costs,  including  attorneys'  fees,
incurred in connection with this case; and

     5.  Grant such further relief as the Court deems just and equitable.

     THE PLAINTIFF DEMANDS A TRIAL BY JURY ON ALL ISSUES SO TRIABLE.


                                          Respectfully submitted,

                                          CYTOGEN CORPORATION
                                          By Its Attorneys,



                                          /s/ Jeffrey W. Moss
                                          --------------------------------------
                                          Jeffrey W. Moss, BBO# 552421
                                          Morgan, Lewis & Bockius LLP
                                          225 Franklin Street, Suite 1705
                                          Boston, Massachusetts   02110
                                          Tel:     617.451.9700

                                          Frank C. Testa (Pro Hac Vice, pending)
                                          Daniel E. Orr (Pro Hac Vice, pending)
                                          Morgan, Lewis & Bockius LLP
                                          502 Carnegie Center
                                          Princeton, New Jersey  08540
                                          Tel.   609.919.6600

Dated:  January 25, 2006


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