Exhibit 10.73

                                                CONFIDENTIAL TREATMENT REQUESTED
                                                                April 30th, 1999

                                Table of Contents

1.       Definitions
1.1      BI PHARMA KG
1.2      BI PHARMA KG Confidential Information
1.3      Cell Line
1.4      Certificate of Analysis
1.5      cGMP
1.6      C225
1.7      Effective Date
1.8      IMCLONE
1.9      IMCLONE Confidential Information
1.10     Master Cell Bank (MCB)
1.11     Manufacturer's Working Cell Bank (MWCB)
1.12     Phase I
1.13     Phase II
1.14     Phase III
1.15     Process
1.16     Product
1.17     Project
1.18     Project Fee
1.19     Project Manager
1.20     Project Team
1.21     Specifications
1.22     Start Date


2.       Cooperation between the Parties in the Course of the Project
2.1      Designation of Project Manager
2.2      Project Team
2.3      Cooperation
2.4      Access to facilities


3.       IMCLONE's Tasks and Responsibilities
3.1      License to Use of IMCLONE Cell Line and Intellectual  Property
3.2      Materials and Information to be Provided
3.3      Activities to be Performed

December 28, 1998

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4.       BI PHARMA KG's Tasks and Responsibilities
4.1      BI PHARMA KG's Tasks
4.2      Control of Cell Line
4.3      Quarantine and Testing
4.4      Phase I/II Development Program
4.5      Responsibility for Failed Fermentations and Downstream Operations
4.6      Materials and Information to be Delivered
4.7      Product to be Delivered
4.8      Prior Approval
4.9      Retention Samples
4.10     Additional Work


5.       Phase I/II to be Conducted on Fixed-Fee Basis


6.       Phase I/II Project Fee


7.       Additional Work / Future Activities
7.1      Additional Work
7.2      Future Activities
7.3      Others


8.       Ownership of Project Data
8.1      General
8.2      Intellectual Property Rights solely covering the Product
8.3      All other Intellectual Property Rights


9.       Representations. Warranties and Indemnification
9.1      IMCLONE
9.2      BI PHARMA KG


10.      Limitation of Liability
10.1     No Warranty of Merchantability of Fitness
10.2     Limitation of Liability
10.3     Maximum Amount

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11.      Confidentiality
11.1     BI PHARMA KG
11.2     IMCLONE
11.3     Exceptions
11.4     Others


12.      Term and Termination
12.1     Term
12.2     Right to Terminate
12.3     Effect of Termination


13.      Miscellaneous
13.1     Force Majeure
13.2     Publicity
13.3     Notices
13.4     Applicable Law
13.5     Compliance with Laws
13.6     Independent Contractors
13.7     Waiver
13.8     Severability
13.9     Entirety
13.10    Assignment

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                   CONTRACT RESEARCH AND DEVELOPMENT AGREEMENT
                                     (C225)


THIS CONTRACT  RESEARCH AND DEVELOPMENT  AGREEMENT  ("Agreement")  is made as of
April 30, 1999 by and among ImClone Systems  Incorporated,  ("IMCLONE"),  having
its principal  business offices at 180 Varick Street,  New York, New York 10014,
U.S.A. and Boehringer  Ingelheim Pharma KG ("BI PHARMA KG") a German corporation
having  its  principal  place  of  business at  Birkendorfer  Strasse  65, 88397
Biberach an der Riss, Federal Republic of Germany.


BACKGROUND

IMCLONE is the  proprietor  of a  hybridoma  cell line [ *** ] which  produces a
monoclonal  antibody  C225 directed  against  Epidermal  Growth Factor  Receptor
(EGFR) as a result of stable transfection with a C225 expression  construct,  as
well as methods for the purification and analysis of C225.

BI PHARMA KG owns specialized cell culture, processing, protein purification and
Iyophilization  facilities  that may be suitable  for  production  of C225,  and
employs  personnel who have experience in production of proteins by cell culture
and purification processes as well as in registration of biopharmaceuticals.

IMCLONE desires to have BI PHARMA KG personnel evaluate, further develop, supply
and scale-up the production process for C225 in BI PHARMA KG's facilities.

IMCLONE  and Dr.  Karl  Thomae  GmbH  (as of  01.01.1998  and in this  Agreement
substituted  by BI Pharma  KG as the  contractual  assignee  of all  rights  and
obligations  thereunder)  have  previously  entered  into  a  Material  Transfer
Agreement  for  Evaluation  dated  November  10/24,  1997 to evaluate  potential
production and supply of C225.

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AGREEMENT

IN CONSIDERATION OF the mutual covenants set forth in this Agreement,  BI PHARMA
KG and IMCLONE hereby agree as follows:

1.       Definitions

1.1      "BI PHARMA KG"
         shall mean Boehringer Ingelheim Pharma KG.

1.2      "BI PHARMA KG Confidential Information"
         shall mean all  technical and other  information  relating to BI PHARMA
         KG's  facilities  and  associated  technologies  that is  disclosed  or
         supplied  to,  IMCLONE  by BI PHARMA KG  (except  IMCLONE  Confidential
         Information)   pursuant  to  this   Agreement,   whether   patented  or
         unpatented,  including,  without limitation,  trade secrets,  know-how,
         processes, concepts,  experimental methods and results and business and
         scientific plans.

1.3      "Cell Line"
         shall mean the IMCLONE cell line [ *** ] that expresses the Product.

1.4      "Certificate of Analysis"
         shall mean a document to be established by mutual agreement  describing
         testing methods and results.

1.5      "cGMP"
         shall mean the regulatory  requirements for current good  manufacturing
         practices  promulgated  by the FDA under  the  Federal  Food,  Drug and
         Cosmetic Act, as amended,  21 C.F.R.  ss. 210 et seq and 21 C.F.R.  ss.
         600-610, as applicable.

1.6      "C225"
         shall mean a  chimerized  monoclonal  antibody  directed  against  EGFR
         produced by the Cell Line.

1.7      "Effective Date"
         shall mean the date first above  written,  which shall be the effective
         date of this Agreement.

1.8      "IMCLONE"
         shall mean  ImClone  Systems  Incorporated  or an  affiliate of ImClone
         Systems Incorporated.

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1.9      "IMCLONE Confidential Information"
         shall  mean  the  Cell  Line,  Process,   Product  and  all  technical,
         scientific  or business and other  materials and  information  that are
         disclosed or supplied to BI PHARMA KG by IMCLONE or developed on behalf
         of  IMCLONE  by BI PHARMA  KG  (excluding  BI  PHARMA  KG  Confidential
         Information) pursuant to this Agreement whether patented or unpatented,
         including,  without  limitation,  trade secrets,  know-how,  processes,
         concepts,  experimental methods and results and business and scientific
         plans.

1.10     "Master Cell Bank (MCB)"
         shall  mean a cell bank  established  by BI PHARMA  KG  derived  from a
         suspension serum-free adapted cell line to be produced at BI PHARMA KG.

1.11     "Manufacturer's Working Cell Bank (MWCB)"
         shall mean a cell bank  established  by BI PHARMA KG  derived  from the
         MCB.

1.12     "Phase I"
         shall refer to process transfer of the Process to a [ *** ] scale at BI
         PHARMA  KG,  continued  scale-up  to a [  ***  ]  and  [  ***  ]  pilot
         fermentation  scale  and  establishment  of a  downstream  purification
         process  according to Appendix 1, all of which has been completed as of
         the Effective Date.

1.13     "Phase II"
         shall  refer to  demonstrating  the  process  at  small  scale [ *** ],
         performing  Product  equivalency  testing  and  establishing  a filling
         process of the corresponding Product as well as the scale-up to [ *** ]
         pilot  scale and cGMP  production  of clinical  grade  material at that
         scale to be undertaken  by BI PHARMA KG pursuant to this  Agreement and
         according  to the  updated  Master  Projectplan  (Appendix  1.1)  dated
         November  1998.  The  agreed  upon  process  format for Phase II of the
         project is given in Appendix 6. [ *** ].

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1.14     "Phase III"
         shall refer to a second  project,  which may be implemented by separate
         agreement  between  IMCLONE and BI PHARMA KG  following  completion  of
         Phase II  activities,  involving  scaling the Process  from the [ *** ]
         fermentation scale implemented in Phase II to the [ *** ].

1.15     "Process"
         shall refer to a proprietary  IMCLONE  process for using the Cell Line,
         including defined  procedures,  equipment and analytical  methodologies
         for in-process control,  release testing and Product  characterization,
         that has been used by IMCLONE to produce the Product at the  laboratory
         scale, which shall be disclosed by IMCLONE to BI PHARMA KG to enable BI
         PHARMA KG to carry out the  Project  or,  if and when  applicable,  the
         modified process after further development and scale up by BI PHARMA KG
         to the [ *** ] fermentation scale.

1.16     "Product"
         shall mean the  biologically  active C225  produced by the Cell Line in
         accordance with the Process.

1.17     "Project"
         shall mean the Phase I and Phase II contract research program described
         herein,  in which IMCLONE shall transfer the Process to BI PHARMA KG to
         be  implemented,  scaled-up and  evaluated at the [ *** ]  fermentation
         scale in and by BI PHARMA  KG's  facility  and  equipment.  The primary
         objectives  of the Project will be to transfer,  establish and scale up
         the Process in the BI PHARMA KG facility, successfully demonstrate that
         Product can be  reproducibly  manufactured in BI PHARMA KG's facilities
         at [ *** ] scale,  and  generate a report  compiling  a summary of data
         generated in the Project. The proposed workscopes and timelines for the
         Project  are laid down in the Master  Projectplans  attached  hereto as
         Appendix 1 and Appendix 1.1.  Phase I has been completed as of the date
         of this Agreement.

1.18     "Project Fee"
         shall have the meaning specified in Section 6 hereof.

1.19     "Project Manager"
         shall have the meaning specified in Section 2.1 hereof.

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1.20     "Project Team"
         shall have the meaning specified in Section 2.2 hereof.

1.21     "Specifications"
         shall mean the  specifications  for the Product and the respective test
         methods   attached   hereto  as   Appendix   5  on  the  basis  of  the
         specifications  provided by IMCLONE and as such  specifications  may be
         amended from time to time by mutual  agreement of IMCLONE and BI PHARMA
         KG according to further development of the Process and Product.

1.22     "Start Date"
         shall  mean  February  1, 1998  (according  to the  Master  Projectplan
         Appendix 1).

2.       Cooperation between the Parties in the Course of the Project

2.1      Designation of Project Manager.
         BI PHARMA KG and IMCLONE shall each identify a Project Manager,  and if
         they choose, the supervisor of the Project Manager. The Project Manager
         or the Project Manager's supervisor will be exclusively responsible for
         communicating  all instructions and information  concerning the Project
         to the  other  party  and  shall be the  person  or people to whom such
         instructions and information are communicated by the other party.  Each
         Project Manager or the Project  Manager's  supervisor will be available
         on a weekly  basis for  consultation  at  prearranged  times during the
         course of the Project or as may  otherwise  be  reasonably  required or
         advisable.  In  the  absence  of the  Project  Manager  or the  Project
         Manager's supervisor, a substitute shall be appointed. Additional modes
         or methods of communication and decision making may be implemented with
         the mutual consent of each party.

2.2      Project Team.
         BI PHARMA KG and IMCLONE shall each name  representatives  to a Project
         Team, which shall consist of  knowledgeable  specialists in appropriate
         disciplines  who shall be  responsible  for planning and  executing the
         Project and any subsequent interactions between the parties. At regular
         intervals,  the Project  Managers shall schedule  meetings between each
         company's  representatives  for the  purpose of  communicating  Project
         updates and providing a forum for strategic  decision  making and rapid
         resolution of issues.

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         Joint  Project  meetings  shall be conducted  by  telephone-conference,
         video-conference  and face to face meetings.  Meeting  minutes shall be
         prepared jointly by the Project Managers to record all issues discussed
         and decisions  made,  subject to final approval of such minutes by both
         parties.  Such  minutes are  considered  to be accepted by a party when
         there is no objection made by such a party within a period of 7 (seven)
         days after such minutes have been received by the respective party.

         The present list of the members of the Project Team is attached  hereto
         as Appendix 2.

2.3      Cooperation.
         BI PHARMA KG and IMCLONE each agree to work together collaboratively on
         the Project as reasonably expeditiously as possible, with the objective
         of completing the Project according to the mutual agreed timelines (see
         Appendix 1 and Appendix 1.1).

         In the course of the Project,  BI PHARMA KG will at all times take into
         consideration and implement the  recommendations  of IMCLONE as long as
         they do not negatively  influence other BI PHARMA KG biotech operations
         and are agreed  upon by the  Project  Team.  In the absence of explicit
         instructions from IMCLONE, BI PHARMA KG shall be entitled to employ its
         reasonable  judgment in carrying out the Project. BI PHARMA KG shall be
         entitled to rely upon any  instructions  or directives  provided by the
         IMCLONE  Project Manager or the IMCLONE  Project  Manager's  supervisor
         and, subject to Sections 4.5 and 4.7 below shall not be responsible for
         failure to achieve  any  objective  or the  inability  to adhere to any
         guideline   due  to  technical   failures,   incomplete   direction  or
         documentation of Process variables,  or other causes beyond the control
         of BI PHARMA KG.

2.4      Access to facilities.
         IMCLONE shall permit  personnel of BI PHARMA KG, upon reasonable  prior
         written notice to IMCLONE,  to visit its facilities during  appropriate
         times to observe the Process and certain analytical procedures for C225
         as  conducted  by  IMCLONE.  BI PHARMA KG shall  permit  IMCLONE,  upon
         reasonable prior notice to BI PHARMA KG, to review the originals of all
         batch records and other primary  documents at its  facilities and shall
         allow IMCLONE  personnel to be present in its facilities at appropriate
         times  (e.g.  to observe  the  implementation  of the  Process).  While
         visiting the facility of the other party, personnel of BI PHARMA KG and
         IMCLONE  shall  comply  with  all  security  and  safety  policies  and
         procedures of the other party.

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3.       IMCLONE's Tasks and Responsibilities

3.1      License to Use of IMCLONE Cell Line and Intellectual Property.
         IMCLONE  hereby grants to BI PHARMA KG a limited,  non-exclusive  right
         and  license,   without  the  right  to  sublicense,   to  use  IMCLONE
         Confidential  Information,  including  but not limited to the Cell Line
         and  Process,  solely for the purpose of enabling BI PHARMA KG to carry
         out its tasks and responsibilities under this Agreement with respect to
         the Project.

3.2      Materials and Information to be Provided.
         To enable BI PHARMA KG to begin the Project, IMCLONE shall provide:

         (a)  10 vials of the MCB  and/or  MWCB for  Project  start,  additional
              quantities may be requested.

         (b)  a  description  of IMCLONE's  methods for testing of the Cell Line
              and its progenitor cell line.

         (c)  documentation  describing the exact composition of the [ *** ] and
              a sufficient  quantity of actual  medium to enable BI PHARMA KG to
              begin to culture the Cell Line upon receipt from IMCLONE;

         (d)  a description  of the Cell Line and of genetic  construct used for
              expression  of the Product (for  registration  according to German
              gene technology law ("Gentechnikgesetz")), and

         (e)  at BI PHARMA KG's  reasonable  request any additional  information
              concerning  the  Process,   analytical  test  methods,   reference
              materials, and any critical reagents to facilitate the Project.

3.3      Activities  to be  Performed.  As the Project is carried  out,  IMCLONE
         shall:

         (a)  use reasonable  efforts to perform the work and tasks as set forth
              and detailed in Appendix 3.

         (b)  at BI PHARMA  KG's  request  and  subject  to  Section  2.4 above,
              arrange for BI PHARMA KG personnel to visit  IMCLONE's  production
              facility  to  observe  and record  the  Process as carried  out by
              IMCLONE in its  facility.  Any such  records  shall be  considered
              IMCLONE Confidential Information.

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4.       BI PHARMA KG's Tasks and Responsibilities

4.1      BI PHARMA KG's Tasks.
         In the course of this Agreement BI PHARMA KG shall perform the work and
         tasks as laid down and detailed in Appendix 4 hereto.

4.2      Control of Cell Line.
         BI  PHARMA KG shall  maintain  (for  safety  reasons  in two  different
         buildings)  the Cell Line in safe and secure  storage under its control
         in its facilities and shall not permit the transfer of the Cell Line to
         any third  party  that is not  specifically  authorized  in  writing by
         IMCLONE (except to a contract laboratory used for the  characterization
         of the  MCB  or  MWCB  under  substantially  the  same  requirement  of
         confidentiality).  BI  PHARMA  KG  shall  comply  with  all  applicable
         regulatory  requirements  relating to general  safety and  biosafety in
         handling the Cell Line and any raw materials used in the Project.

4.3      Quarantine and Testing.
         BI PHARMA KG will  quarantine and test samples of the Cell Line already
         provided to it in order to verify  that the Cell Line is  suitable  for
         introduction into BI PHARMA KG's facilities. The quarantine and testing
         time is estimated to be about 2 (two) months.

4.4      Phase I/II Development Program.
         Following  quarantine testing of the MWCB (see Appendix 4) BI PHARMA KG
         will transfer and establish the production  process at laboratory scale
         ( [ *** ]  fermentation  scale)  on the  basis of  Process  information
         supplied by IMCLONE. The agreed upon process format for Phase II of the
         Project is given in Appendix 6.  Material  derived  from such a process
         will be tested for analytical  equivalence with reference material from
         IMCLONE. Remaining quantities may be used by IMCLONE at its discretion.
         A scale-up will then be performed to the [ *** ] fermentation scale and
         cGMP  material [ *** ] for  clinical  trials  will be  produced at this
         scale. The workscopes and timelines for such a program are given in the
         Master  Projectplans  (see Appendix 1 and Appendix 1.1). The production
         of further clinical material at [ *** ] fermentation scale, if required
         by IMCLONE,  has to be agreed upon separately in writing,  and shall be
         reflected in an amendment to this  Agreement in  accordance  within the
         terms set forth herein.

4.5      Responsibility for Failed Fermentations and Downstream Operations.

         [ *** ]

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              [ *** ]

         (b)  [ *** ]

4.6      Materials and Information to be Delivered.
         BI PHARMA KG will provide  IMCLONE  with the  following  materials  and
         information at the times indicated:

         (a)  a summary of the test results  generated during the 2 (two) months
              quarantine  period  within 30 (thirty)  days  following the end of
              such period;

         (b)  within 2 (two) months  following  completion  of each Phase of the
              Project (Phase I and Phase II), a report to IMCLONE,  as laid down
              detailed in Appendix 7 including,  a summary of the data BI PHARMA
              KG  collects  in the course of the  Project  and  Certificates  of
              Analysis for release of Product for clinical use, if any;

         (c)  other interim results as reasonable in appropriate time periods or
              requested by IMCLONE, as mutually agreed by the Project Team.

4.7      Product to be Delivered.
         BI PHARMA KG shall  supply  Product to  IMCLONE  from the [ *** ] pilot
         scale and all purified Product (cGMP grade) from the [ *** ] scale runs
         performed by BI PHARMA KG. BI PHARMA KG shall also provide IMCLONE with
         samples  of  vialed  Product  that  is  produced  by  it.  All  Product
         delivered,  if any, shall conform with the Specifications which have to
         be  mutually  agreed  upon as laid down in  Appendix 5 and BI PHARMA KG
         shall issue a Certificate of Analysis covering such Specifications.

         If the Product is  asserted by IMCLONE not to meet the  Specifications,
         both parties shall re-test the Product. If IMCLONE and BI PHARMA KG are
         not able to agree,  whether the Product meets the Specifications or not
         and the parties are unable to resolve  their  differences,  then either
         party may refer the matter to an independent specialized institution of
         international  reputation agreeable to both parties for final analysis,
         which shall be binding on both parties hereto.

         All Product  produced in the course of the Project shall be retained by
         BI PHARMA KG and stored  under  conditions  specified  by IMCLONE  (and
         reasonably  acceptable  to BI PHARMA KG) not longer  than 1 (one) year,
         and  delivered to IMCLONE as  instructed by IMCLONE and at the cost and
         risk of IMCLONE.

4.8      Prior Approval.
         Prior to  implementing  any  deviation  from the Project,  BI PHARMA KG

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         shall  notify  IMCLONE and obtain the  written  approval of the Project
         Manager of IMCLONE or other person designated in writing by IMCLONE.

4.9      Retention Samples.
         According to a sampling  plan to be agreed upon by the Project Team, BI
         PHARMA KG shall  isolate,  identify and retain samples of raw materials
         used in  fermentations  carried  out in the course of the  Project,  of
         Process media at appropriate time points in each  fermentation,  and of
         Product  at each  stage of  purification.  Retention  samples  shall be
         provided  promptly to IMCLONE at its request.  Shipment shall be at the
         cost and risk of IMCLONE.

4.10     Additional Work.
         On  request  of  IMCLONE,   BI  PHARMA  KG  shall  perform   additional
         development  work to sustain the progress of the Project on  conditions
         in terms of money,  time and scope to be subject to mutual agreement of
         the  parties   hereto  and  defined  in  an  amendment  to  the  Master
         Projectplans attached hereto as Appendix 1 and Appendix 1.1.

5.       Phase I/II to be Conducted on Fixed-Fee Basis

         The Project  shall be  conducted by BI PHARMA KG for IMCLONE on a fixed
         fee basis, in consideration of payment by IMCLONE of the Project Fee.

         The  estimated  duration of the Project shall be [ *** ] from the Start
         Date as outlined in Appendix 1 and Appendix 1.1. Phase I of the Project
         has been completed as of the Effective Date.

6.       Phase I/II Project Fee

         IMCLONE shall pay BI PHARMA KG a Project Fee of DM 8, 950,000
         (eightmillionninehundredandfiftythousand   Deutsche   Mark)   for   the
         services  provided in carrying out the Project as defined in Appendix 1
         and Appendix 1.1,  regardless of the  favorability or usefulness of the
         results  (see  Section 4.5 above).  Of this amount to date DM 3,130,000
         has been paid for the completion of Phase I.

         This fee includes all fees for BI PHARMA KG's services under the Master
         Projectplans  for Phase I and Phase II,  including  but not limited to,
         fees for Cell Line  validation,  facility  use, raw  material  testing,
         in-process   testing  services  including  bulk  and  finished  product
         testing, environmental monitoring as appropriate, and other calibration
         and validation

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         activities  required to  facilitate  the  successful  completion of the
         technology  transfer and  production of the clinical  grade material at
         the [ *** ] fermentation scale.

         Disposal of organic and hazardous waste is included in the Project Fee.
         The Project Fee shall be payable in installments,  each  non-refundable
         when paid,  as described in Appendix 1 and Appendix  1.1. To the extent
         BI PHARMA KG is  required  to repeat any  fermentations  or  downstream
         operations  pursuant to Section 4.5 (b) above, any installment  related
         to the  completion  of the  fermentation  or  downstream  operation  or
         delivery of the Product, as the case may be, shall not be payable until
         such  fermentation or downstream  operation or delivery of Product,  as
         the case may be, has been completed.

         The cost of commercially  available  materials purchased by IMCLONE for
         use at BI PHARMA KG to  support  development  in GLP and cGMP  shall be
         creditable to the applicable invoice.

         Each invoice shall be payable within 30 (thirty) days following receipt
         thereof.

7.       Additional Work / Future Activities

7.1      Additional Work.
         BI PHARMA KG and IMCLONE may confer to  determine  if  additional  work
         relating  to Phase I or Phase  II  should  be  undertaken  pursuant  to
         subsequent  agreement  between BI PHARMA KG and IMCLONE.  Neither party
         shall be obligated to conduct any further undertakings on behalf of the
         other  except as may be mutually  agreed and set forth in a  subsequent
         written agreement.

         7.2      Future Activities.

                  [ *** ]

7.3      Others.
         IMCLONE  shall not assert any right to use BI PHARMA KG  facilities  at
         any  future  date as a result  of its use of BI  PHARMA  KG  facilities
         pursuant to this Agreement,  nor shall BI PHARMA KG assert any right to
         use or have access to the Cell Line, Process, Product, MCB or MWCB as a
         result of its activities pursuant to this Agreement.

8.       Ownership of Project Data

8.1      General.
         All  information  and  intellectual  property  rights  relating  to the
         transfer of information  under Section 4.6 above, with the exception of
         BI PHARMA KG Confidential Information,  shall be the sole and exclusive
         property  of

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         IMCLONE and IMCLONE shall have the right to use such
         information for any purpose without further obligation to BI PHARMA KG.

         For the purpose of this Agreement all  information  regarding BI PHARMA
         KG's  facility and  technical  equipment  shall be considered BI PHARMA
         KG'S Confidential Information.

8.2      Intellectual Property Rights solely covering the Product.
         Any and all  intellectual  property rights solely covering the Product,
         including,  but not limited to, patents and patent applications arising
         out of the activities  performed under this Agreement shall be the sole
         and exclusive  property of IMCLONE,  which shall have the sole right to
         file such  applications  and will meet all costs in  relation  thereto.
         Upon request of IMCLONE, BI PHARMA KG will assign any and all rights as
         necessary to vest such ownership in IMCLONE.

8.3      All other Intellectual Property Rights.
         All other intellectual property rights that arise out of the activities
         performed  under  this  Agreement,  and that do not  cover  solely  the
         Product  shall be the sole and  exclusive  property of BI PHARMA KG and
         IMCLONE shall be granted a  non-exclusive,  royalty-free  and worldwide
         license solely for use to the Product.

9.       Representations. Warranties and Indemnification

9.1      IMCLONE.
         IMCLONE hereby represents, warrants and agrees that:

         (a)  IMCLONE is free to supply the Cell Line and  IMCLONE  Confidential
              Information to BI PHARMA KG;

         (b)  IMCLONE is not aware of any special or unusual hazards involved in
              handling the Cell Line or Product;

         (c)  IMCLONE has full corporate  authority to enter into this Agreement
              and this Agreement is binding upon IMCLONE in accordance  with its
              terms; and

         (d)  [ *** ]

9.2      BI PHARMA KG.
         BI PHARMA KG hereby represents, warrants and agrees that:

         (a)  BI PHARMA KG has the  lawful  right to use the  facilities  and BI
              PHARMA KG  Confidential  Information  to be used for  purposes set
              forth in this Agreement;

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         (b)  BI PHARMA KG is not aware of any special or unusual  hazards  that
              would  arise as a result of its  carrying  out of the  Project  as
              planned;

         (c)  BI  PHARMA  KG has full  corporate  authority  to enter  into this
              Agreement  and this  Agreement  is  binding  upon BI  PHARMA KG in
              accordance with its terms; and

         (d)        [ *** ]

         (e)  BI PHARMA KG warrants  that the Project shall be conducted as laid
              down in Appendix 1 and  Appendix 1.1 and in  accordance  with this
              Agreement and, when appropriate, in compliance with cGMP, and that
              any  documentation  of Project  results or procedures  provided to
              IMCLONE  by BI  PHARMA  KG  shall  be  accurate  in  all  material
              respects.
              With regard to the results see Section 4.5 above.

10.      Limitation of Liability

10.1     No Warranty of Merchantability or Fitness.
         Subject to Section 9.2 above, BI PHARMA KG shall provide the results of
         the  Project to IMCLONE  without any  warranty of any kind,  express or
         implied,    including,    without   limitation,   any   warranties   of
         merchantability or fitness for a particular purpose.

         10.2     Limitation of Liability.

                  [ *** ]

10.3     Maximum Amount.
         BI PHARMA KG  undertakes to use its best efforts to perform the Project
         under the Master Projectplans and to meet the target dates set forth in
         Appendix 1 and Appendix 1.1 hereto. [ *** ].

11.      Confidentiality

11.1     BI PHARMA KG.
         BI PHARMA KG shall not disclose IMCLONE Confidential Information to any
         person other than its employees or employees of affiliated companies of
         the Boehringer  Ingelheim group who are bound by similar obligations of
         confidentiality  and who have a need to know such  information in order
         to perform their duties in carrying out the Project hereunder.

11.2     IMCLONE.
         IMCLONE shall not disclose any BI PHARMA KG Confidential Information to
         any person other than:

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         (a)  its  employees  or  consultants  who are  bound  by  substantially
              similar obligations of confidentiality and who have a need to know
              such information in order to provide  direction to BI PHARMA KG or
              evaluate the results of the Project; or

         (b)  regulatory  authorities,  for example,  the FDA, that require such
              information in order to review an IND or other regulatory filing.

11.3     Exceptions.
         The obligations of confidentiality  applicable to IMCLONE  Confidential
         Information and BI PHARMA KG Confidential  Information  shall not apply
         to any information that is:

         (a)  known publicly or becomes known  publicly  through no fault of the
              recipient;

         (b)  learned by the recipient  from a third party  entitled to disclose
              it;

         (c)  developed by the recipient  independently of information  obtained
              from the disclosing party as evidenced by prior written records of
              the recipient;

         (d)  already known to the recipient  before receipt from the disclosing
              party, as shown by its prior written records;

         (e)  required  to be  disclosed  by law,  regulation  or the order of a
              judicial or administrative authority;  provided that the recipient
              notifies the disclosing party immediately upon receipt at any such
              order or becoming aware of any such law or regulation, or released
              with the prior written consent of the disclosing party.

11.4     Others.
         No right or license  under any patent or  proprietary  right is granted
         hereunder  by  virtue  of  the   disclosure  of  IMCLONE   Confidential
         Information  or  BI  PHARMA  KG  Confidential   Information  except  as
         expressly  provided herein.  The obligations of both parties under this
         Section  11  shall  survive  the  expiration  or  termination  of  this
         Agreement.  Both  IMCLONE  and BI PHARMA KG shall  use  reasonable  and
         customary precautions to safeguard IMCLONE Confidential Information and
         BI PHARMA KG  Confidential  Information,  including  ensuring  that all
         employees or consultants  who are provided  access to such  information
         are  informed  of the  confidential  and  proprietary  nature  of  such
         information and understand that all such  information is required to be
         maintained confidential.

12.      Term and Termination

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12.1     Term.
         This Agreement shall come into force as of the date first above written
         and commence  retroactively as of the Start Date and, unless terminated
         earlier as provided herein, shall terminate upon the date of payment of
         the last sum due  hereunder,  or upon the date  when the last  services
         required to be performed hereunder are performed,  whichever date shall
         last occur unless specifically extended by further written agreement.

12.2     Right to Terminate.
         If it becomes apparent to either party at any stage of the Project that
         it will not be  possible to carry out the  Project  for  scientific  or
         technical  reasons or as a result of Force  Majeure  (as  described  in
         Section 13 below),  the parties shall permit 30 (thirty)  business days
         for  discussion to resolve,  if possible,  the  scientific or technical
         issue  giving rise to the  problem.  If the parties fail to resolve the
         problem within this 30 (thirty) day period, either party shall have the
         right to terminate this Agreement, effective upon written notice to the
         other.

         In the event of such a termination initiated by IMCLONE, [ *** ]

         Either party may terminate this Agreement effective upon written notice
         if either of the following events occurs:

         (a)  The other party commits a breach of this  Agreement and the breach
              is not  remedied  within 30  (thirty)  days  after the  receipt of
              notice  identifying  the breach,  requiring its remedy and stating
              the intent of the party to terminate in the absence of remedy; or

         (b)  The other party (i) becomes unable to pay its debts as they become
              due,  (ii)  suspends  payment of its debts,  (iii)  enters into or
              becomes   subject  to  corporate   rehabilitation   or  bankruptcy
              proceedings  or  liquidation   or   dissolution,   (iv)  makes  an
              assignment  for the benefit of its  creditors  or (v) seeks relief
              under any similar laws for debtor's relief.

12.3     Effect of Termination.

         Upon the expiration or termination of this Agreement:

         (a)  At the request of IMCLONE,  BI PHARMA KG shall deliver at the cost
              and risk of IMCLONE  all vials of the Cell  Line,  the MCB and the
              MWCB, as well as  description of all methods  relating  thereto to
              IMCLONE or its  designee  and shall  promptly  return all  IMCLONE
              Confidential  Information  to  IMCLONE;  except for a single  copy
              and/or sample for documentation purposes only and

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         (b)  IMCLONE  shall  promptly  return  all BI  PHARMA  KG  Confidential
              Information  to BI PHARMA  KG,  except  for a single  copy  and/or
              sample for documentation purposes only.

              The   respective   rights  of  BI  PHARMA   KG  and   IMCLONE   to
              indemnification  as set  forth in  Sections  9 and 10 above  shall
              survive  termination  of this Agreement with respect to any claims
              that relate to or derive from the Project, or any acts or failures
              to act, of either BI PHARMA KG or IMCLONE in  connection  with the
              Project that occur prior to termination.

13.      Miscellaneous

13.1     Force Majeure.
         Neither  party  shall be in  breach of this  Agreement  if there is any
         failure of performance  under this Agreement (except for payment of any
         amounts  incurred  hereunder prior to Force Majeure)  occasioned by any
         act of God,  fire, act of government or state,  war,  civil  commotion,
         insurrection, embargo, prevention from or hindrance in obtaining energy
         or other  utilities,  labor  disputes of  whatever  nature or any other
         reason beyond the control of either party.

13.2     Publicity.
         Except as required by law (e.g. SEC-requirements),  no press release or
         other form of publicity  regarding the Project or this Agreement  shall
         be permitted to be published  unless both parties have indicated  their
         consent  to the form of the  release.  Notwithstanding  the  foregoing,
         IMCLONE may elect to issue a press  release or other form of  publicity
         regarding the Project at any time,  but shall first notify BI PHARMA KG
         of such  issuance  and  provide  BI  PHARMA KG with an  opportunity  to
         comment thereon. Nothing in this Section 13.2 shall prevent the parties
         from disclosing this Agreement as required by applicable laws, rules or
         regulations.

13.3.    Notices.
         Any notice  required or permitted to be given hereunder by either party
         shall be in writing and shall be (i) delivered personally, (ii) sent by
         registered  mail,  return receipt  requested,  postage prepaid or (iii)
         delivered  by  facsimile  with  immediate  telephonic  confirmation  of
         receipt,  to the addresses or facsimile  numbers set forth below: If to
         BI PHARMA KG:                       Boehringer Ingelheim Pharma KG
                                             Birkendorfer Stra(beta)e 65
                                             D-88397 Biberach an der Riss
                                             Federal Republic of Germany
                                             Attention: Dr. Wolfram Carius
                                             Fax:      + 0049 73 51/54-98049
                                             Phone + 0049 73 51/54-9421

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         If to IMCLONE:                 ImClone Systems Incorporated
                                        180 Varick Street, 7th Floor
                                        New York, New York 10014
                                        Attention: Mr. John B. Landes,
                                                     Vice President,
                                        Business Development and General Counsel
                                        Fax:      001 212 645 1405
                                        Phone: 001 212 645 2054

         Each notice  shall be deemed given (i) on the date it is received if it
         is  delivered  personally,  (ii) 1  (one)  day  after  the  date  it is
         postmarked  if it is sent  by  certified  United  States  mail,  return
         receipt requested,  postage prepaid or (iii) on the date it is received
         if it is sent by facsimile with immediate  telephonic  confirmation  of
         receipt.

13.4.    Applicable Law.
         This  Agreement  shall be governed by and construed in accordance  with
         the laws of Germany without regard to its choice of law principles. The
         courts of the place of  domicile  of BI PHARMA KG shall have  exclusive
         jurisdication over all legal matters and proceedings hereunder.

13.5     Compliance with Laws.
         BI PHARMA KG shall  perform  the work  hereunder  in  conformance  with
         GLP/cGMP, as applicable,  and all German and/or EU laws, ordinances and
         governmental rules or regulations pertaining thereto.

13.6.    Independent Contractors.
         Each of the parties  hereto is an  independent  contractor  and nothing
         herein  contained  shall be deemed to constitute  the  relationship  of
         partners,  joint  venturers,  nor of  principal  and agent  between the
         parties hereto. Neither party shall hold itself out to third persons as
         purporting  to act on behalf  of, or serving as the agent of, the other
         party.

13.7.    Waiver.
         No waiver of any term, provision or condition of this Agreement whether
         by conduct or otherwise in any one or more instances shall be deemed to
         be or  construed  as a further or  continuing  waiver of any such term,
         provision or condition or of any other term,  provision or condition of
         this Agreement.

13.8     Severability.
         If  any  provision  of  this   Agreement  is  held  to  be  invalid  or
         unenforceable by a court of competent jurisdiction all other provisions
         shall  continue in full force and effect.  The parties  hereby agree to
         attempt to substitute for

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         any invalid or unenforceable provision a valid or enforceable provision
         which achieves to the greatest  extent  possible the economic legal and
         commercial objectives of the invalid or unenforceable provision.

13.9     Entirety.
         This Agreement,  including any exhibits and appendices  attached hereto
         and  referenced  herein,  constitutes  the  full  understanding  of the
         parties and a complete  and  exclusive  statement of the terms of their
         agreement,  and no  terms,  conditions,  understandings  or  agreements
         purporting to modify or vary the terms thereof shall be binding  unless
         it is hereafter made in writing and signed by both parties.

13.10    Assignment.
         Neither  party may assign this  Agreement to a third  party,  except an
         affiliate  (including a subsidiary or division),  and either IMCLONE or
         BI PHARMA KG may assign this  Agreement in connection  with the sale of
         all or substantially all of such party's assets or similar transaction.
         This Agreement  shall be binding upon the successors and assigns of the
         parties  and the name of a party  appearing  herein  shall be deemed to
         include the names of its successors and assigns.

IN WITNESS WHEREOF,  the parties have caused this Agreement to be executed as of
the Effective Date.

Biberach, ...........................1999          New York, April 30, 1999

Boehringer Ingelheim Pharma KG                     ImClone Systems Incorporated

                              ppa.

/s/ Dr. Jacob             /s/ Prof. R.G. Werner     /s/ John B. Landes


Dr. Jacob                 Prof. R. G. Werner         By: John B. Landes
Member of the Board       Head of Industrial
                          Biopharmaceuticals         Title: VP, General Counsel

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Appendices:
-----------
Appendix 1:          Master Projectplan including Project Timeline
Appendix 1.1:        Updated Master Projectplan including Project timeline
Appendix 2:          Project Team
Appendix 3:          IMCLONE s Tasks in Detail
Appendix 4:          BI PHARMA KG s Tasks in Detail
Appendix 5:          Test Methods and Specifications for C225
Appendix 6:          Protein A Process Format
Appendix 7:          Summary Data Reports for Phase I and Phase II

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<PAGE>

Appendix 1  Page 1 of 2

Master Projectplan: C225
ImClone Systems, Inc./Bl Pharma KG
Forecast of proposed Workscope and Cost Estimate

[ *** ]


<PAGE>

Appendix 1.1 Page 1 of 4

Update May 1999 Ma ster Projectplan: C225
ImClone Systems, Inc./Bl Pharma KG
Forecast of proposed Workscope and Cost Estimate

  [***]


<PAGE>

<TABLE>
<CAPTION>
                                   Appendix 2


             Function                   Boehringer Ingelheim               ImClone

<S>                                     <C>                          <C>
        Project Team Leader             Dr. Helmut Hoffmann          Mr. Ronald Martell (?)
                                                                     Ms. Martie Bohn

    Head of Process Development         Dr. Helmut Hoffmann                  (?)

Cell Banking and Characterization,      Dr. Stefanos Grammatikos     Ms. Betsy Hornberger
           Virus Testing                                             Dr. Daniel Velez
                                                                     Dr. S. Joseph Tarnowski

   Small Scale Cell Culture Labs        Dr. Wolfgang Noe             Mr. Joel Goldstein
                                                                     Mr. Rajeew Gupta
                                                                     Dr. Daniel Velez
                                                                     Dr. S. Joseph Tarnowski

     Fermentation Pilot Plant           Dr. Ralph Kempken            Mr. Joel Goldstein
                                                                     Mr. Rajeew Gupta

       Downstream Processing            Dr. Joachim Walter           Dr. Daniel Velez
                                                                     Mr. Joel Goldstein
                                                                     Dr. S. Joseph Tarnowski

   Protein Analytical Chemistry         Dr. Michael Schluter         Ms. Betsy Hornberger

        Process Validation              Mr. Norbert Hentschel        Mr. Glen Noonan

              Filling                   Mr. Hans Hormann             Mr. Edward Patten

            Regulatory                  Dr. Uwe Bucheler             Ms. Gretchen Toolan

           Documentation                Dr. Uwe Bucheler             Mr. Edward Patten

         Quality Assurance              Mrs. Bettina Schulz

             Contract                   Mrs. Kipping
</TABLE>


<PAGE>

                                   Appendix 3


                           ImClone's Tasks in Details


[ *** ]


<PAGE>

                                   Appendix 4


                         BI PHARMA KG's Tasks in Detail


       [ *** ]


<PAGE>

Appendix 5: Test Methods and Specifications for C225


[ ***]


<PAGE>

                                   Appendix 6

                            [ *** ] A Process Format


[***]


<PAGE>

                                   Appendix 7


                  Summary Data Reports for Phase I and Phase II