CONFIDENTIAL MATERIALS OMITTED AND FILED SEPARATELY
                  WITH THE SECURITIES AND EXCHANGE COMMISSION.
                           ASTERISKS DENOTE OMISSIONS.

                                                                    EXHIBIT 10.4



                       MANUFACTURING AND SUPPLY AGREEMENT

         THIS  AGREEMENT  made  effective  as of January 1, 1999,  among  DuPont
Pharmaceuticals  Company,  a  Delaware  general  partnership,  having a place of
business  at 331  Treble  Cove  Road,  North  Billerica,  MA 01862  (hereinafter
"DuPont"),  Berlex  Laboratories,  Inc. a Delaware corporation having offices at
300  Fairfield  Road,  Wayne,  NJ  07470  (hereinafter   "Berlex")  and  Cytogen
Corporation,  a Delaware corporation,  having its principal place of business at
600 College Road East, Princeton, NJ 08540 (hereinafter "Cytogen").

         WHEREAS,   Cytogen   owns  or  holds   licenses  to   patents,   patent
applications,  manufacturing and marketing  authorizations and know-how relating
to the Product, and has exclusively licensed same to Berlex;

         WHEREAS, Berlex desires DuPont to manufacture and distribute Product as
directed by Berlex;

         WHEREAS,  DuPont is capable of manufacturing,  processing and packaging
Product,  and possesses the requisite plant,  equipment and personnel to produce
Product  in  accordance  with  necessary  governmental   authorizations  and  in
accordance with the Specifications; and

         WHEREAS,  the parties agree that DuPont will undertake the manufacture,
distribution,  order  processing  and customer  service  relating to the Product
specified  under  this  Agreement  solely  for  the  account  of  Berlex  and in
accordance with all of the terms and conditions specified below.

         NOW  THEREFORE,  IN  CONSIDERATION  of the  rights  conferred  and  the
obligations  assumed  herein,  and  intending to be legally  bound,  the parties
hereby agree as follows:

1.0      DEFINITIONS

The  following  terms shall,  unless the context  otherwise  requires,  have the
following meanings, respectively:

1.01     "ACTIVE PHARMACEUTICAL INGREDIENT" or "API" means the chemical compound
         samarium-153  complexed with ethylene  diamineteiramethylene-phosphonic
         acid ("EDTMP").

1.02     "AFFILIATE"  means any corporation or other entity which  controls,  is
         controlled  by,  or is  under  common  control  with a  party  to  this
         Agreement.  A  corporation  or other  entity  shall be  regarded  as in
         control  of another  corporation  or entity if it owns or  directly  or
         indirectly  controls  more than fifty percent (50%) of the voting stock
         or other ownership interest of the other corporation or entity, or bias
         the power to elect or  appoint  more than  fifty  percent  (50%) of the
         members of the governing body of the corporation or other entity.

                                      -1-

<PAGE>

1.03     "CHANGE" shall have the meaning set forth in Section 2.8(a).

1.04     "COMPONENTS" means EDTMP, all labeling material,  packaging   material,
         starting material and  intermediates  and  excipients  required for the
         manufacture of Product.

1.05     "CONFIDENTIAL INFORMATION" means a party's technology,  data, know-how,
         or information  whether  written or oral,  technical or  ton-technical,
         including financial statements,  reports,  prig, trade secrets,  secret
         processes,  formulas, customer data (including customer lists), and the
         like, that relates to the manufacture,  packaging,  order processing or
         distribution of the Product, and that is disclosed to the other party.

1.06     "COST OF MANUFACTURE OR COM" means Dupont's cost of manufacture as
         described on Exhibit A.

1.07     "COST OF SUPPORT SERVICES OR COSS" means DuPont's cost of customer
         support services as described on Exhibit A.

1.08     "FDA" means the United States Food and Drug Administration.

1.09     "INVENTORY"  means all  inventories of Components  and  work-in-process
         produced  or held by or on  behalf of  DuPont  in  connection  with the
         manufacture of the Product in accordance  with the  Specifications  and
         contract  requirements,  but, for greater certainty,  shall not include
         the API.

1.10     "KNOW-HOW"  means the  trade-secrets,  know-how,  processes,  formulae,
         techniques,  procedures, test data and other technical information owed
         by a party hereto relating to the Product.

1.11     "SPECIFICATIONS"  means the  Product,  synthesis,  formula,  processing
         specifications,  packaging  specifications,  quality control provisions
         and quality assurance  provisions contained within the NDA for Product,
         EDTMP,  API,  samarium  chloride,  all  forms  of  samarium  oxide  and
         Components.  Specifications  shall not be changed by font  without  the
         prior written approval of Cytogen and Berlex.

1.12     "PRODUCT"  means a formulation  containing API  manufactured  according
          to the  Specifications  and in finished dosage form.

1.13     "BATCH" means one manufacturing  process run within the validated scale
         (as defined in the NDA) within DuPont's usual range of actual yield.

1.14     "EFFECTIVE DATE" means the date first shown above.

1.15     "NDA" means the approved New Drug Application for Product, as it may be
         supplemented  or amended from time to time, and documents  incorporated
         therein by reference.

1.16     EXHIBITS.  The following exhibits are attached hereto and  incorporated
         in and are deemed to be an integral part of this Agreement:

                                      -2-
<PAGE>

                  Exhibit A         -       Prices

2.0      MANUFACTURE AND SUPPLY OF PRODUCTS

2.1      Manufacture.  Berlex appoints  DuPont its  manufacturer of the Product,
         and DuPont accepts such appointment.  DuPont will manufacture on behalf
         of Berlex, one Batch of Product per week for such weeks that Berlex and
         its customers submit orders.  Notwithstanding anything to the contrary,
         Berlex may qualify  others for the  manufacture  and supply of Product,
         and may qualify  itself to  manufacture  Product.  DuPont will  provide
         reasonable  assistance,  at  Berlex's  cost,  in  support  of any  such
         qualification.

2.2      Scheduling.  In consultation with Berlex, and in accordance with orders
         submitted for the Product,  DuPont will  determine  scheduling of Batch
         runs and shipment of Product.

2.3      Packaging.  DuPont will package Product in the packaging containers and
         with labels,  package  inserts and other  labeling that are approved by
         Berlex. Berlex may propose changes to labels, Product inserts and other
         labeling for the Product,  which  changes shall be submitted by the NDA
         holder to all applicable  governmental agencies and other third parties
         responsible for the approval of the Product, if required, provided that
         DuPont will submit to the Commonwealth of Massachusetts. Berlex will be
         responsible  for any and all  costs  relating  to any and all  labeling
         changes,  except for regulatory  activities  conducted by Cytogen,  the
         costs of which shall be borne by Cytogen.

2.4      Quality Control and Assurance.

         (a)      DuPont shall  manufacture and supply the Product in accordance
                  with the Specifications.

         (b)      DuPont  shall   perform  such  quality   control  and  quality
                  assurance testing as is required by the Specifications.

         (c)      DuPont shall  perform the approved  stability  program for the
                  Product.

         (d)      DuPont will  promptly  notify  Berlex and Cytogen in the event
                  any  test  reveals  contamination,   lack  of  sterility,   or
                  degradation  beyond  Specifications  in any Back Cytogen will,
                  with the concurrence of Berlex,  fide any reports  required by
                  the applicable regulations.

2.5      Primary   Representatives.   Each   party   shall   appoint  a  primary
         representative  ("Primary  Representative")  who shall  coordinate work
         carried  out  hereunder  with the  other  party's  representative.  The
         Primary  Representatives  shall be the day-to-day  contacts between the
         parties hereto and shall receive  copies of all written  correspondence
         exchanged  between the parties with respect to the designated  work. In
         the event either party identifies an issue relating to the manufacture,
         quality,  delivery,  customer  service,  or the like  with  respect  to
         Product, the Primary  Representatives  shall promptly confer to resolve
         such issue. If a Primary  Representative  leaves the employ of a party,
         an equally competent, mutually acceptable, Primary Representative shall
         be assigned by such party.

                                      -3-
<PAGE>

2.6      Firm Order.

         (a) Berlex  hereby firmly orders front DuPont a maximum of one Batch of
         Product per week as needed to fill orders  received  during the term of
         this Agreement.

         (b) In the event DuPont  determines based on a lack of orders that in a
         particular  week Berlex will not require  manufacture of a Batch,  then
         DuPont shall promptly so inform Berlex.  After  receiving  confirmation
         from Berlex,  DuPont will use reasonable  efforts to minimize  variable
         cost  expenditures.  In such  circumstances  Berlex shall pay DuPont as
         required under Section 3.1(b).

2.7      Raw Materials. DuPont will be responsible for purchasing all Components
         and the API.

2.8      Change in Specifications

          (a)  Except as provided below,  DuPont will not be responsible for any
               cost increases  associated with  implementation  of any change in
               the  Specifications,  Components,  API or  manufacturing  process
               ("Change"),  regardless of the reason for the change. Any and all
               such cost  increases will be borne by Berlex (except that Cytogen
               shall  be  responsible  for  costs   associated  with  regulatory
               activities  relating to Changes that are carried out by Cytogen),
               and  shall  be paid to  DuPont  prior  to  implementation  of any
               change.  Moreover, after the first year, any increase in cost per
               Batch  associated  with  implementation  of any  Change  shall be
               passed  directly  to  Berlex.   The  price  change  shall  become
               effective  only with respect to those orders of Product which are
               manufactured  in  accordance  with  the  revised  Specifications.
               Berlex  shall not be  responsible  for the cost of  changes  made
               solely for the convenience of DuPont.

          (b)  Notwithstanding  any Change  implemented  in accordance  with the
               terms  of  (a)  above,   Berlex   agrees  to   purchase   Product
               manufactured by DuPont based upon any "old" Specifications at the
               then-current price for that Product.  In addition,  Berlex agrees
               to purchase,  at DuPont's  cost,  all Inventory  and  Components,
               utilized  under  the  "Old"   Specifications   and  purchased  or
               maintained by DuPont in order to fill firm written orders, to the
               extent that such  Inventory  and/or  Components  can to longer be
               utilized under the revised  Specifications and cannot be utilized
               in any other  products  of DuPont and cannot be  returned  to the
               supplier.  Open purchase orders for Components no longer required
               under any revised Specifications which were placed by DuPont with
               suppliers in order to fill firm written orders shall be cancelled
               where  possible,  and  where  such  orders  are  not  subject  to
               cancellation without penalty,  shall be assigned to and satisfied
               by Berlex.  This section  2.8(b) shall not be  applicable  to any
               Change made solely for the convenience of DuPont.

2.9      Shipments.  DuPont shall ship and deliver the Product  C.I.P.  DuPont's
         shipping point to such locations as are specified in orders received by
         DuPont  pursuant to INCOTERMS  1990. The common carrier used and method
         of shipment  shall be agreed with  Berlex.  After  1999,  Berlex  shall

                                      -4-
<PAGE>

         either pay the common  carrier  directly  or  reimburse  DuPont for the
         shipping cost, as evidenced by invoices of common carriers.

2.10     Invoices.  DuPont shall   promptly  notify  Berlex of each  shipment of
         Product  hereunder.  Berlex  will  be  responsible  for  invoicing  the
         customer.

2.11     Other DuPont Obligations. In addition to manufacture of Product, DuPont
         will provide certain  additional  services relating to customer support
         and technical  support.  DuPont will take Product orders  directly from
         Berlex's  customers;  ship ordered  Product to Berlex's  customers  (as
         provided in Section 2.9);  carry out license  verification of customers
         and common carriers; provide technical support; and provide Berlex with
         a written or electronic,  if within the  capabilities  of DuPont and at
         the option of Berlex,  report  detailing  names of  customers  ordering
         Product and  quantities  ordered.  Within the  capabilities  of DuPont,
         DuPont will provide such  additional  information  relating to ordering
         and shipping of Products as Berlex may reasonably  request from time to
         time.

2.12     Waste. The parties acknowledge and agree that DuPont shall not have any
         responsibility for waste generated after Product is shipped from font's
         site,  except  as  provided  in  Section  4.8 and 4.9.  Notwithstanding
         anything  to the  contrary,  Berlex will be  responsible  for all costs
         associated  with  clean-up and removal of unused  Product  and/or waste
         related to Product and/or waste arising from use of Product, other than
         waste at DuPont's  manufacturing  site, which is the  responsibility of
         DuPont.

2.13     Back-Up  Manufacturer.  In the event that DuPont is unable to supply or
         distribute  the  quantities of Product  ordered,  Berlex shall have the
         right to arrange for supply of Product by a third party. At the request
         of Berlex,  DuPont agrees to take reasonable steps to assist Berlex, at
         Berlex's expense (reimbursement to be limited to DuPont's out of pocket
         expenses),   in  qualifying  a  third  party   selected  by  Berlex  to
         manufacture and distribute the Product during the period that DuPont is
         unable to do so.

2.14     International  Supply.  The  parties  recognize  that  the  Product  is
         presently  approved for marketing in the United States and Canada,  and
         that  Berlex  will be  marketing  the  Product in Canada as well as the
         United  States.  In addition,  Berlex  intends to market the Product in
         other  countries  of North  America  and  South  America  as  marketing
         approvals  are obtained in such  countries.  DuPont agrees to cooperate
         with  Berlex  and  Cytogen as is  reasonable  in the  circumstances  in
         respect to  packaging  and  labeling  the Product for  distribution  in
         countries other than the United States. DuPont, Berlex and Cytogen will
         cooperate  in   providing   documentation   required  by   governmental
         authorities  relating  to the  export of the  Product  from the  United
         States  and the import of the  Product  into  countries  other than the
         United States.  Berlex shall promptly  reimburse DuPont for any and all
         incremental costs incurred by DuPont under this Section 2.14.

3.0      PRICE, PAYMENT AND COST

3.1      Payment.

                                      -5-
<PAGE>

          (a)  As consideration  for DuPont's  manufacture and supply of Product
               and the provision of customer  service and support,  as described
               in Section  2.0,  Berlex  shall pay DuPont the  amounts  shown on
               Exhibit A. Such payments  shall be due and payable  within thirty
               (30) days following the end of each month.

          (b)  The parties  acknowledge that in the first year of this Agreement
               Berlex is  obligated  to pay the fixed  monthly fee  described in
               Exhibit A,  regardless of whether  DuPont  actually  manufactures
               Product.  In the years following the first year of this Agreement
               Berlex  will pay  DuPont an amount  equal to COM plus COSS plus a
               certain  margin,  as described in Exhibit A. In those later years
               the parties  still intend that DuPont  receive  payments  even in
               those weeks when Berlex does not require  manufacture of Product.
               Therefore,  in the event  that  DuPont  receives  no  orders  for
               Product  during a particular  week,  then Berlex shall pay DuPont
               the full  amount  otherwise  due under  Section  3.1(a)  less any
               amount DuPont is able to save on variable cost. As an example, if
               in the fifth year of this Agreement (i) DuPont receives no orders
               for a particular  week and (ii) DuPont is able to avoid  purchase
               of certain raw  materials for such week and (iii) DuPont does not
               manufacture a Batch in that week, then Berlex would pay DuPont as
               follows:  (COM +  [**]%)  plus  (COSS + [**]%)  less any  savings
               DuPont realized by avoiding purchases the certain raw materials.

          (c)  After the first year of this  Agreement,  in the event  DuPont is
               unable to  manufacture  Batches  for a period  grater than thirty
               (30) days,  then following such thirty (30) day period,  Berlex's
               obligation to pay DuPont under Section  3.1(a) shall be suspended
               until such time as DuPont resumes  manufacture of Batches.  Also,
               after the first  year  Berlex  shall  have no  obligation  to pay
               DuPont for Batches that do not meet Specifications.

3.2      Additional Batches. The manufacture of Batches beyond the commitment of
         DuPont set forth in Section 2.1 (each an  "Additional  Batch") shall be
         undertaken only with the agreement of DuPont. In the first year of this
         Agreement,  Berlex  shall pay DuPont an amount  equal to $[**] for each
         Additional  Batch  manufactured at Berlex's  request.  In the following
         years, Berlex shall pay DuPont an amount per Batch based on the monthly
         costs as set forth on Exhibit A. Payments  under this Section 3.2 shall
         be due and payable  within  thirty (30) days  following  the end of the
         month during which the Additional Batch was manufactured.

4.0      RECORDS, AUDITS, ADERS, RECALLS, RETURNS

4.1      Records and  Accounting  by DuPont.  DuPont  shall keep  records of the
         manufacture,  testing  and  shipping of the Product as required by law,
         including  those required by the FDA, the NRC and the  Commonwealth  of
         Massachusetts.  Copies  of  such  records  and  samples  shall  be made
         available  to  Berlex  and/or  Cytogem  upon its  request  and shall be
         retained by DuPont and be  available to Cytogen and Berlex for a period
         of one (1) year  following  the date of  product  expity,  or longer if
         required by law.

                                      -6-
<PAGE>

4.2      Regulatory Inspections.  DuPont will inform Berlex and Cytogen promptly
         of any inspection or audit by any  governmental  agency,  including the
         FDA,  related to the Product.  Moreover,  DuPont will inform Berlex and
         Cytogen of the result of any such audit or  inspection  within 24 hours
         of the  conclusion  of such audit or  inspection.  DuPont will promptly
         provide  Berlex  and  Cytogen  with  copies  of  any  government-issued
         inspection  observation  reports,  including FDA form 483s, and related
         correspondence, that affect the Product DuPont, Cytogen and Berlex will
         cooperate in resolving any concerns with the FDA or other  governmental
         agency.

4.3      Inspections.  Berlex and Cytogen will each have the right, no more than
         once in each  year (or more  frequently  if  agreed  to by the  parties
         hereto  such  agreement  not  to  be  unreasonably  withheld.)  and  on
         reasonable prior notice, to inspect those DuPont facilities used in the
         manufacturing,  packaging,  storage,  testing, shipping or receiving of
         Product Such inspections may include GMP inspections and system audits,
         including  observation  of the  actual  process of  manufacture  of the
         Product.  Representatives of Berlex and Cytogen will have access during
         audits  to all  Product  related  documents,  records,  reports,  data,
         procedures,  facilities,  and  all  other  information  required  to be
         maintained by FDA regulations or the requirements of other governmental
         agencies.

4.4      Coordination  of Safety and Complaint  Reporting.  The parties agree to
         comply  with  all  legal  obligations  imposed  in  the  United  States
         concerning the collection, investigation, and governmental reporting of
         adverse  reactions and  complaints  relating to the Product,  including
         without  limitation with respect to the United States 21 CFR 312.32 and
         21 CFR 314.80(a).  Promptly following the Effective Date the respective
         departments of the parties  responsible for handling  adverse  reaction
         monitoring and complaints will jointly  develop a written  procedure to
         govern their communication  concerning such matters,  such that each of
         the parties will have the ability to comply with its legal  obligations
         and contractual undertakings.

4.5      Recall  Action.  Only the NDA holder,  and Berlex if Cytogen is the NDA
         holder,  may  initiate a recall  action.  DuPont  shall  inform the NDA
         holder and Berlex if DuPont  determines  it is  necessary to initiate a
         recall,  withdrawal or field  correction.  If Berlex or Cytogen  should
         decide to initiate a Product  recall,  withdrawal  or field  correction
         because  of supply by DuPont of  Product  that does not  conform to the
         Specifications,  it will notify  DuPont and the other party and provide
         DuPont  and the  other  party  a copy of its  recall  letter  prior  to
         initiation  of the recall.  DuPont  will  assist  Berlex and Cytogen in
         their  investigation  to determine the cause and extent of the problem.
         All FDA contacts and coordination of any recall activities will handled
         by  Berlex.  Notwithstanding  anything  to the  contrary,  in the event
         DuPont recommends initiating a recall, but Cytogen and/or Berlex do not
         agree to commence  such recall,  then DuPont shall bear  absolutely  no
         liability  whatsoever with respect to any Batch of Product that was the
         subject of DuPont's recall recommendation, and Section 7.1(b) shall not
         apply to such Batch of Product.

4.6      Recall  Expenses.  If a  recall,  withdrawal  or  field  correction  is
         required because of Product that did not conform to the  Specifications
         at time of shipment  from  DuPont,  then  DuPont  shall pay for its own
         out-of-pocket expenses for such recall, withdrawal or field correction.
         DuPont also shall be responsible for Berlex's and Cytogen's  reasonable
         out of pocket expenses  occasioned by such recall,  withdrawal or field

                                      -7-
<PAGE>

         correction.  DuPont shall also be responsible  for the  manufacture and
         distribution of replacement Product. The NDA holder will be responsible
         for any and all costs  associated  with a recall,  withdrawal  or field
         correction for any other reason,  including DuPont's  reasonable out of
         pocket expenses.

4.7      Records.  DuPont will maintain  complete and accurate  records for such
         periods as may be required by  applicable  law or  regulation,  but not
         less than 1 year, of all Product supplied under this Agreement.

4.8      Product  Returns.  DuPont  will have the  responsibility  for  handling
         customer  returns of the Product in  accordance  with a procedure to be
         agreed with  Berlex.  Customer  credit for returns  will be at the sole
         discretion of Berlex.

4.9      Waste. In its  performance of this Agreement,  DuPont shall comply with
         all  laws  and  regulations  applicable  to  the  generation,  storage,
         shipment and disposal of waste generated in the manufacture of Product.

5.0      TERM, RENEWAL AND TERMINATION

5.1      Term.  Unless  terminated early in accordance with any of Sections 5.1,
         5.2,  5.3, or 5.5, this  Agreement  will be in effect and will continue
         for a period of five (5) years. This Agreement will automatically renew
         for two (2) year periods unless  terminated by DuPont on two (2) years'
         written  notice or terminated  in accordance  with any of Sections 5.2,
         5.3, or 5.5.  Berlex  shall have the farther  right to  terminate  this
         Agreement at any time on two (2) years written  notice to DuPont.  This
         agreement may be  terminated  at any time with the mutual  agreement of
         the parties.

5.2      Breach.  Either  Berlex or DuPont may terminate  this  Agreement at any
         time on written  notice if another  party  breaches a material  term of
         this  Agreement  and fails to remedy the breach  within sixty (60) days
         after receiving written notice of the breach.

5.3      Insolvency.  DuPont or Berlex may terminate this Agreement  immediately
         in its  entirety  if Berlex (in the vase of  termination  by DuPont) or
         DuPont  (in the case of  termination  by Berlex)  files a  petition  of
         bankruptcy,  is adjudged  bankrupt,  takes  advantage of any insolvency
         act, or executes a bill of sale,  deed of trust,  or assignment for the
         benefit of creditors.

5.4      Survival.  The rights and  obligations  contained in sections  covering
         warranties,    indemnification   and   confidentiality   will   survive
         termination of this  Agreement,  as will any rights to payment or other
         rights or obligations  that have accrued under this Agreement  prior to
         termination.  Termination will not affect a Party's liability by reason
         of any act, default, or occurrence prior to termination.

5.5      Berlex's  Further  Right to  Terminate.  Berlex  shall have the further
         right to terminate this Agreement with respect to Berlex's  obligations
         on sixty  (60) days  notice to DuPont  and  Cytogen  in the event  that

                                      -8-
<PAGE>

         Berlex's license agreement with Cytogen for Product is terminated.

5.6      Repurchase at  Termination.  If this  Agreement is  terminated,  Berlex
         shall  purchase,  at DuPont's out of pocket cost, the Inventory and the
         API  applicable  to the  Product  which  were  purchased,  produced  or
         maintained by DuPont in  contemplation  of filing firm written  orders,
         prior to notice of termination being given.

6.0      REPRESENTATIONS AND WARRANTIES

6.1      Authority.  Each party  represents  and  warrants  that it has the full
         right and  authority to enter into this  Agreement,  and that it is not
         aware of any  impediment  that would inhibit its ability to perform its
         obligations  hereunder.  Each  party  further  warrants  that it  shall
         perform   hereunder  in  accordance   with  all   applicable   law  and
         regulations.

6.2      Manufacturing  Warranty  DuPont  warrants  that  each  lot  of  Product
         supplied  to  Berlex  will  be  manufactured  in  accordance  with  the
         Specifications.

6.3      ALL WARRANTIES  GRANTED BY DUPONT  HEREUNDER ARE IN LIEU OF AND EXCLUDE
         ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, ARISING BY OPERATION OF LAW
         OR OTHERWISE,  INCLUDING WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
         PARTICULAR PURPOSE.

7.0      INDEMNITY

7.1      (a) BY BERLEX AND CYTOGEN.  Berlex and Cytogen shall each indemnify and
         hold harmless DuPont,  its officers,  agents,  and employees,  from and
         against  any and all  loss,  damage,  claim,  injury,  cost or  expense
         including  reasonable   attorneys'  fees  and  expenses  of  litigation
         ("Claims"),  which result from any sale, use or disposition of Product,
         including  Claims  arising  in  connection  with  patent  infringement,
         trademark  infringement,  product liability theories, or any illness or
         personal injury, including death or property damage.

         (b) BY DUPONT. DuPont shall indemnify and hold harmless Berlex, Cytogen
         and each of their respective officers,  agents, and employees, from and
         against any and all Claims  relating to the manufacture or distribution
         of  Product  that  result  solely  from  the  material  breach  of this
         Agreement by DuPont or the gross  negligence  or willful  misconduct of
         DuPont.

         (c) SHARED  LIABILITY.  In the event that a Claim involves  allegations
         that the negligent (gross negligent or material breach,  in the case of
         DuPont)  reckless  (in the  case  of  Berlex  or  Cytogen)  or  willful
         misconduct of each of Berlex, Cytogen, and DuPont contribute materially
         to any such liability, cost, loss or expense stemming from the Product,
         then Cytogen,  Berlex,  and DuPont each shall be  responsible  for that
         portion  of  said  liability,  cost,  loss or  expense  to  which  such
         misconduct contributed.

                                      -9-
<PAGE>

7.2      (a) INDEMNIFICATION  PROCEDURES.  Each indemnified party agrees to give
         the indemnifying  party prompt written notice of any Claim or discovery
         of fact upon which such indemnified party intends to base a request for
         indemnification under Section 7.1. Each party shall furnish promptly to
         the other,  copies of all papers and  official  documents  received  in
         respect of any Claim.  With respect to any Claim relating solely to the
         payment of money  damages and which will not result in the  indemnified
         party  becoming  subject to  injunctive  or other  relief or  otherwise
         adversely  affecting  the  business  of the  indemnified  party  in any
         manner,  and as to which the indemnifying party shall have acknowledged
         in writing the obligation to indemnify the indemnified party hereunder,
         the indemnifying  party shall have the sole right to defend,  settle or
         otherwise  dispose of such  Claim,  on such  terms as the  indemnifying
         party, in its sole discretion, shall deem appropriate. The indemnifying
         party shall obtain the written consent of the indemnified  party, which
         shall  not be  unreasonably  withheld,  prior  to  ceasing  to  defend,
         settling or otherwise disposing of any Claim if as a result thereof the
         indemnified Party would become subject to injunctive or other equitable
         relief or any remedy  other than the  payment of money,  which  payment
         would be the responsibility of the indemnifying party. The indemnifying
         party shall not be liable for any settlement or other  disposition of a
         Claim by the indemnified  party which is reached without the consent of
         the indemnifying  party. Except as provided above, the reasonable costs
         and expenses,  including  reasonable fees and  disbursements of counsel
         incurred by any indemnified  party in connection with any Claim,  shall
         be reimbursed on a quarterly basis by the indemnifying  party,  without
         prejudice to the indemnifying  party's right to contest the indemnified
         party's right to indemnification and subject to refund in the event the
         Indemnifying  party is ultimately held not to be obligated to indemnify
         the indemnified party.

         (b) SHARED  LIABILITY  PROCEDURE.  In the event  that a claim  involves
         allegations of shared liability pursuant to Section 7.1(c), the parties
         will  insofar  as  possible   endeavor  to  coordinate   their  defense
         strategies  (including  a joint  defense  agreement if warranted by the
         circumstances).  Expenses shall be allocated  between the parties based
         on the proportion of the loss  attributable to each. If the parties $re
         unable to agree on the division of expenses  during the pendency of the
         Claim;  then  each  party  shall  bear  its own  expenses,  subject  to
         reimbursement by or of the party following the conclusion of the Claim.

8.0      CONFIDENTIALITY

8.1      Disclosure to DuPont  Promptly  attar the Effective  Date,  Cytogen and
         Berlex  will  provide  to DuPont any and all  Confidential  Information
         necessary for DuPont to perform hereunder.

8.2      Restrictions  on Disclosure and Use by Both Parties.  No party will use
         the Confidential Information provided by the other party or disclose it
         to any  third  party  except  as  necessary  to carry  out the  party's
         obligations  under this Agreement If either party finds it necessary to
         disclose such Confidential  Information to a third patty, they will not
         do so without first  obtaining  written  consent of the other party and
         entering  into an agreement  with the third party which binds the third
         party to the same  obligations  of restricted use and disclosure as are

                                      -10-
<PAGE>

         undertaken by the parties in this Agreement.  Section 8.2 shall survive
         termination of this Agreement.

8.3      Exceptions.  The  obligations  of  Section  8.2 will  not  apply to any
         information  which (a) is in the  possession of the receiving  party at
         the time of receipt  from the  disclosing  party,  as shown by existing
         records,  (b) is or becomes available to the public through no fault of
         the receiving party, (c) is disclosed to the receiving party by a third
         party entitled to disclose it, or (d) is independently developed by the
         receiving  party  without  reliance  on  information  supplied  by  the
         disclosing  party, as evidenced by the records of the receiving  party,
         or (e) is required by law or judicial  order to be disclosed,  in which
         case the party  required to make the  disclosure  shall provide as much
         advance notice as possible to the disclosing party, shall to the extent
         possible allow the  disclosing  party to seek a protective  order,  and
         shall to the extent possible minimize the information to be disclosed.

9.0      MISCELLANEOUS

9.1      Compliance  with Laws.  Each party,  in connection with its performance
         under this  Agreement,  shall comply with all applicable  laws,  rules,
         regulations, orders and guidelines.

9.2      Permit,  Licenses.  The NDA holder shall promptly  reimburse DuPont for
         all expenses  relating to DuPont's  obtaining and maintaining  licenses
         and permits specifically required for the manufacture of Product.

9.3      Trademarks. Each party hereby acknowledges that no party has, nor shall
         it acquire,  any  interest in any of the other  party's  trademarks  or
         trade  names  unless  otherwise  expressly  agreed to in  writing.  The
         parties  agree  not to use any  trademark  or trade  name of the  other
         party, except as specifically authorized by the other party.

9.4      Reports.  DuPont will supply the NDA holder on an annual basis, product
         data,  including  release test results,  complaint  test  results,  all
         investigations (in manufacturing,  testing and storage),  and the like,
         which are  reasonably  required in order to complete the Annual Product
         Review  report and the NDA annual  report that are required to be filed
         by the NDA holder with the FDA or any other  report that is required to
         be filed with any other  government  agency. A copy of any such report'
         will be contemporaneously disclosed to the party to thus Agreement that
         is not the NDA holder.

9.5      Independent Contractors.  The parties shall be deemed to be independent
         contractors,  and this  Agreement  shall  not be  construed  to  create
         between DuPont and Cytogen and Berlex any other  relationship  such as,
         by way of example only,  that of  employer-employee,  principal  agent,
         joint venturer,  co-partners or any similar relationship, the existence
         of which is expressly denied by the parties hereto.

9.6      No Waiver.  A party's  failure to require  another party to comply with
         any provision of this  Agreement shall  not be deemed a waiver of such
         provision or any other provision of this Agreement.

                                      -11-
<PAGE>

9.7      Assignment.  Neither  party may  assign  this  Agreement  or any of its
         rights or obligations  hereunder  except with the prior written consent
         of the other  parties,  except  that Berlex and Cytogen may assign this
         Agreement  to each other or their  respective  Affiliates  without  the
         consent of DuPont.  Assignment by DuPont shall require only the consent
         of Berlex.

9.8      Force Majeure.  No party shall be liable for the failure to perform its
         obligations  under this  Agreement if such failure is  occasioned  by a
         contingency beyond such party's reasonable control,  including, but not
         limited to, strikes or other labor disturbances, lockouts, riots, wars,
         fires,  floods or storms. For the purposes of this Section 9.8, failure
         of a vendor to supply DuPont with  Components or raw materials shall be
         considered a force majeure  event.  A party claiming a right to excused
         performance under this Section 9.8 shall  immediately  notify the other
         party in writing  of the  extent of its  inability  to  perform,  which
         notice shall specify the occurrence beyond its reasonable  control that
         prevents such  performance and an estimate of the time the inability to
         perform is anticipated to last.

9.9      Notices.   Any  notice,   approval,   instruction   or  other   written
         communication  requited or permitted  hereunder  shall be sufficient if
         made or given to the other party by personal delivery or by sending the
         same by first class mail,  postage  prepaid to the mailing  address set
         forth below:

         If to DuPont:

         DuPont Pharmaceuticals Company
         Medical Imaging Division
         331 Treble Cove Road
         North Billerica, MA
         Attn: Vice President, Manufacturing

         If to Berlex:

         All notices to Berlex other than routine correspondence relating to and
         including orders,  revisions,  routine  customer-related  matters,  and
         invoicing shall be addressed to:

         Attention:                 Vice President, Corporate Development
                                    Berlex Laboratories, Inc.
                                    340 Changebridge Road
                                    Montville, NJ 07045-1000

         Address for express delivery:
                                    340 Changebridge Road
                                    Pine Brook, NJ 07050-9714

         With a copy addressed to:
         Attention:                 General Counsel
                                    Berlex Laboratories, Inc.
                                    300 Fairfield Road
                                    Wayne, NJ 07470-7358

                                      -12-
<PAGE>

         Routine  correspondence  addressed to Berlex  relating to and including
         orders,  revisions,  customer-related  matters and  invoicing  shall be
         addressed to:

         Attention:                 Director, Customer Services
                                    Berlex Laboratories, Inc.
                                    300 Fairield Road
                                    Wayne; NJ 07470-7358

         If to Cytogen:

         Attention:                 Chief Executive Officer
                                    Cytogen Corporation
                                    600 College Road East - CN 5308
                                    Princeton, New Jersey 08540-5309

         or to such other  addresses  provided to the other party in  accordance
         with the terms of this Section 9.9.  Notices  hereunder shall be deemed
         to have been sufficiently made or given when delivered.

9.10     Entire Agreement.  This Agreement constitutes the full, complete, final
         and integrated  Agreement  between the parties  hereto  relating to the
         subject  matter  hereof and  supersedes  all  previous  written or oral
         negotiations,  commitments,  agreements, transactions or understandings
         with respect to the subject matter hereof. Any modification,  amendment
         or  supplement  to this  Agreement  must be in  writing  and  signed by
         authorized representatives of both parties.

9.11     Headings.  The titles  and headings herein are for convenience only and
         shall not be used to interpret  or construe the terms and conditions of
         this Agreement.

9.12     Singular  Terms.  Except  as  otherwise  expressly  provided  herein or
         unless the  context otherwise requires,  all references to the singular
         shall include the plural as well.

9.13     Execution in Counterparts.  This Agreement may be executed in three (3)
         counterparts,  each of which  shall be deemed an  original,  but all of
         which together shall constitute one and the same instrument.

9.14     Governing  Law.  This  Agreement  shall be  construed  and  enforced in
         accordance with the laws of the State of Delaware, without reference to
         its conflicts of law provisions,  and the United States of America. The
         State of Delaware and federal courts within  Delaware shall be the only
         courts of competent jurisdiction.

9.15     Publicity.  Each party  agrees not to issue any press  release or other
         public  statement,  or any  communication or response to a third party,
         whether oral or written,  disclosing the existence of this Agreement or
         any  information  or activity  relating to this  Agreement  without the
         prior written  consent of the other  parties,  provided  however,  that
         neither  party  will be  prevented  from  complying  with  any  duty of
         disclosure it may have pursuant to law or governmental regulation.

                                      -13-
<PAGE>


9.16     Contingent Agreement.  This Agreement is made contingent upon execution
         of the Amendment to the Letter Agreement, of even date, between DuPont
         and Cytogen.

                                      -14-

<PAGE>

         IN WITNESS WHEREOF, the duly authorized  representatives of the parties
have executed this Agreement as of the dates set forth below,

DUPONT PHARMACEUTICALS COMPANY

By:      /s/ William J. DeLorbe
    ----------------------------------------------------------

Name:    William J. DeLorbe
      --------------------------------------------------------

Title:   Executive Vice President, Medical Imaging

Date:    November 13, 1998



BERLEX LABORATORIES, INC.

By:      /s/ C.R. Willis, Jr.
    ----------------------------------------------------------

Name:    C.R. Willis, Jr.
      --------------------------------------------------------

Title:   Vice President, Corporate Development

Date:    November 13, 1998




CYTOGEN CORPORATION

By:      /s/ H. Joseph Reiser, Ph.D.
    ----------------------------------------------------------

Name:    H. Joseph Reiser, Ph.D.
      --------------------------------------------------------

Title:   President & Chief Executive Officer

Date:    November 13, 1998


                                      -15-
<PAGE>


                                    EXHIBIT A

                                     PRICES
                                     ------


  Year              Manufacture and Supply            Customer Support Services
 ------                   of Product                 -------------------------
                    ----------------------
  1st                    $[**]/month                       included

  2nd                    COM plus [**]%                    COSS plus [**]%

  3rd                    COM plus [**]%                    COSS plus [**]%

  4th                    COM plus [**]%                    COSS plus [**]%

  5th                    COM plus [**]%                    COSS plus [**]%


With respect to years 2-5,  monthly COM and COSS shall be calculated as follows:
Monthly  COM for year two  shall be  equal  to $[**]  plus the  increase  in the
Producer  Price  Index  for  year  1  for  Industrial  Commodities,   Drugs  and
Pharmaceuticals  (06-3),  published by the United States  Department of Commerce
("PPI") (or if publication of such index ceases, an appropriate substitute index
agreed by the  parties).  For years 3, 4, and 5 the monthly COM shall be the sum
of the monthly COM for the previous  year;  plus the increase in the PPI for the
previous year.

Monthly  COSS for year 2 shall be $[**]  per  order.  For  years 3, 4, and 5 the
monthly COSS shall be the sum of the monthly COSS for the previous year plus the
PPI for the previous year.

The increase in the PPI for the previous  year shall be determined as of January
1st of each year based on the last full  twelve  calendar  months for which data
are available.


                                      -16-