<PAGE>

                                                                Exhibit 10.25


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                       Page: 1
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          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.

                                                                      May 5,1999

                                SUPPLY AGREEMENT

                                 (ON CAMPATH-1H)

<TABLE>

<S>                                                                                                     <C>
Supply Agreement.........................................................................................3
WITNESSETH...............................................................................................3
1.    DEFINITIONS........................................................................................3
      1.1   "L&I Partners, L.P.".........................................................................3
      1.2   "Contract Research and Development Agreement"................................................4
      1.3   "Product-price"..............................................................................4
      1.4   "Capacity"...................................................................................4
      1.5   "Product"....................................................................................4
      1.6   "Bulk Product"...............................................................................4
      1.7   "Final Product"..............................................................................4
      1.8   "Finished Product"...........................................................................4
      1.9   "Specifications".............................................................................4
      1.10  "Process"....................................................................................4
      1.11  "Certificate of Analysis"....................................................................5
      1.12  "Certificate of Compliance"..................................................................5
      1.13  All other terms..............................................................................5
2.    SUPPLY.............................................................................................5
      2.1   Exclusivity..................................................................................5
      2.2   Capacity, Process and Specifications.........................................................5
      2.3   Approved Facility............................................................................6
      2.4   Subcontracting...............................................................................6
      2.5   Rolling Forecasts............................................................................6
      2.6   Quantities beyond the [**] forecasts.........................................................7
      2.7   Delivery.....................................................................................7
      2.8   Minimum quantities...........................................................................7
      2.9   Exclusivity/Competition......................................................................7
3.    QUALITY/WARRANTY/LIABILITY/INDEMNIFICATION.........................................................8
      3.1   Warranty/Limitation..........................................................................8
      3.2   Tests of the Product and agreed upon Audits..................................................8
      3.3   Defective Product (including loss and inaccurate quantity)...................................8
      3.4   Indemnification by L&I Partners, L.P.........................................................8
      3.5   Infringement of intellectual property rights.................................................9
      3.6   Limitation of Warranty/Liability/Maximum Amount..............................................9
      3.7   Delivery/Risk of Loss........................................................................9
      3.8   Documentation................................................................................9
      3.9   Indemnification by BI Pharma KG.............................................................10
      3.10  Superiority.................................................................................10
4.    SUPPORT REGARDING POST LICENSING ISSUES...........................................................10
5.    PRICE AND PAYMENT.................................................................................10
</TABLE>


<PAGE>



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<TABLE>
<S>                                                                                                     <C>
      5.1   Product-price...............................................................................10
      5.2   Surcharge...................................................................................10
      5.3   Payment Conditions..........................................................................10
            (1) PREMARKETING  PHASE:....................................................................10
            (2) MARKETING PHASE:........................................................................10
            (3) SURCHARGE: .............................................................................10
            (4) INVOICE/TRANSFER OF PAYMENTS:...........................................................10
      5.4   Currency/Conversion.........................................................................11
      5.5   Prices Adjustments..........................................................................11
      5.6   Introduction of the Euro....................................................................12
6.    CONFIDENTIALITY...................................................................................13
      6.1   BI Pharma KG................................................................................13
      6.2   L&I Partners, L.P...........................................................................13
      6.3   Exceptions..................................................................................13
7.    LICENSE...........................................................................................14
      7.1   Use of L&I Partners, L.P. Cell Line and Intellectual Property...............................14
      7.2   No other Right or License...................................................................14
8.    TERM AND TERMINATION..............................................................................14
      8.1   Basic Term..................................................................................14
      8.2   Automatic Extension.........................................................................14
      8.3   Early Termination...........................................................................15
      8.4   Termination in case of Breach of Agreement..................................................15
      8.5   Premature Termination.......................................................................15
9.    MISCELLANEOUS.....................................................................................15
      9.1   Force Majeure...............................................................................15
      9.2   Publicity...................................................................................16
      9.3   Notices.....................................................................................16
      9.4   Applicable Law/Jurisdiction.................................................................17
      9.5   Compliance with Laws........................................................................17
      9.6   Independent Contractors.....................................................................18
      9.7   Waiver......................................................................................18
      9.8   Severability................................................................................18
      9.9   Entirety....................................................................................18
      9.10  Assignment..................................................................................18
Appendices..............................................................................................20
</TABLE>



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                       Page: 3
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                                SUPPLY AGREEMENT

                                 (ON CAMPATH-1H)

THIS SUPPLY-AGREEMENT ("Agreement") is made effective as of June 4, 1999
("Effective Date"), by and between

L&I PARTNERS, L.P.
a limited partnership of the State of Delaware, having its principal business
offices at 11550 IH 10 West, Suite 300, San Antonio, TX 78230, USA

                              (hereinafter referred to as "L&I PARTNERS, L.P."),

and

BOEHRINGER INGELHEIM PHARMA KG,
whose registered office is at Birkendorfer StraBe 65, 88397 Biberach an der
Riss, Federal Republic of Germany

                                    (hereinafter referred to as "BI PHARMA KG").

WITNESSETH

WHEREAS Dr. Karl Thomae GmbH and L&I Partners, L.P. have - among others -
concluded a Contract Research and Development Agreement regarding the research
and development of a method to produce CAMPATH-1H in a commercial scale, which
has been assigned to BI Pharma KG as of January 1, 1998; and

WHEREAS L&I Partners, L.P. has all rights to the Product and is the owner of the
Process and

WHEREAS L&I Partners, L.P. wishes BI Pharma KG, and BI Pharma KG accepts, to
manufacture and supply L&I Partners, L.P. with Product for commercial use,
manufactured in accordance with the Process.

NOW THEREFORE, the parties hereto agree as follows:

1.       DEFINITIONS

In this Agreement the following terms shall have the meanings indicated:

1.1      "L&I PARTNERS, L.P."
         means L&I Partners, L.P., Inc.  as laid down first above.


<PAGE>


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          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


1.2      "CONTRACT RESEARCH AND DEVELOPMENT AGREEMENT"
         means the agreement on CAMPATH-1 H (the humanized IgG 1 monoclonal
         antibody specifically directed against CD 52 between Dr. Karl Thomae
         GmbH and L&I Partners, L.P dated August 5,1997 regarding the
         development of the Process and assigned to BI Pharma KG effective as of
         January 1, 1998.

1.3      "PRODUCT-PRICE"
         means BI Pharma KG's prices for Product, Bulk Product, Final Product
         and/or Finished Product (as the case may be) to be calculated on the
         basis of the assumptions set forth in Appendix 1.

1.4      "CAPACITY"
         means BI Pharma KG's at a given time total production capacity per year
         reserved for CAMPATH-1H in accordance with the Process. The maximum
         Capacity shall be [**]kg/year of Product based on the assumptions set
         forth in Appendix 1 unless otherwise agreed upon with a reasonable
         leadtime.

1.5      "PRODUCT"
         means any product containing CAMPATH-1H in Bulk Product or as Final
         Product or as Finished Product its sole or combined active ingredient
         and produced according to the Process.

1.6      "BULK PRODUCT"
         means Product which has been purified to a concentrated form and can be
         stored in a liquid or frozen form under appropriate conditions.

1.7      "FINAL PRODUCT"
         means unlabelled final container containing liquid Product.

1.8      "FINISHED PRODUCT"
         means Final Product and also labeled and packaged.

1.9      "SPECIFICATIONS"
         mean the specifications to be enclosed hereto as Appendices 3 for
         Product, Final Product and Finished Product produced and supplied
         hereunder by BI Pharma KG. These Appendices will be agreed upon by the
         parties after the finalization of the Process.

1.10     "PROCESS"
         shall be the final Process for manufacturing Product developed and
         agreed by the parties according to the Contract Research and
         Development Agreement. The actual Process is laid down in documents
         added hereto as Appendix 4. For the time being the Process is a
         [****].



<PAGE>



L&I Partners, L.P./BI Pharma KG:  Supply Agreement                       Page: 5
--------------------------------------------------------------------------------


1.11     "CERTIFICATE OF ANALYSIS"
         shall mean a document describing testing methods and results, the
         accuracy of which has been certified by the issuing party.

1.12     "CERTIFICATE OF COMPLIANCE"
         shall mean a document (a) listing the expiration date and quantity of a
         particular batch of Bulk Drug, Final Product and/or Finished Product,
         (b) certifying that such batch was manufactured in accordance with all
         Specifications, current cGMP, the BLA/EMEA dossier for the Product (as
         applicable), and (c) certifying that such batch is acceptable for
         manufacturer release. The agreed upon format is attached hereto as
         Appendix 6.

1.13     ALL OTHER TERMS
         used herein shall have the same meaning as defined in the Contract
         Research and Development Agreement.

2.       SUPPLY

2.1      EXCLUSIVITY
         Subject to L&I Partners, L.P.'s right to manufacture or have
         manufactured by a third party Bulk Product and/or Final Product and/or
         to have a third party to produce Final Product and/or Finished Product
         from Bulk Product produced by L&I Partners, L.P. as expressly stated in
         this Agreement, BI Pharma KG will manufacture and supply Product to L&I
         Partners, L.P. or its designee(s) exclusively throughout the world
         during the full term of this Agreement and according to the provisions
         of this Agreement (incl. rolling forecasts and minimum quantities). L&I
         Partners, L.P. will purchase Product from BI Pharma KG throughout the
         world for the period of this Agreement. This does not prevent L&I
         Partners, L.P. to have Product in reasonable quantities manufactured
         for clinical testing purposes solely elsewhere.

         To minimize the theoretical risk of the exclusiveness the parties have
         agreed on a stock policy as laid down in Appendix 5.

2.2      CAPACITY, PROCESS AND SPECIFICATIONS
         Subject to Section 3 below BI Pharma KG undertakes to supply L&I
         Partners, L.P. or its designee(s) with the quantities of Product
         ordered by L&I Partners, L.P. within its Capacity. All manufacture of
         Product hereunder will be made in accordance with the Process and will
         be delivered in agreed form suitably packed as specified in the
         Specifications.

         In case BI Pharma KG cannot produce sufficient commercial quantities of
         the Product (provided that L&I Partners, L.P. is adhering to the
         provisions of this Agreement (e.g. the rolling forecast system) then
         L&I Partners, L.P. shall have the right to manufacture or have
         manufactured by a third party the missing quantities; only in this case
         and if reasonably necessary, BI Pharma KG shall


<PAGE>

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         Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


         assist L&I Partners, L.P. in transfer of the Process for a limited time
         not to exceed [**] skilled people and [**] L&I Partners, L.P.

         Capacity may be increased by BI Pharma KG on the written request of L&I
         Partners, L.P. with a reasonable leadtime, not to be less than [**],
         if the requested increase requires major investment and/or
         construction and if L&I Partners, L.P. commits itself to the taking
         over of the expense of the increase of capacity to be reasonably agreed
         upon by the Parties.

2.3      APPROVED FACILITY
         All quantities of Product will be produced in a production facility
         designated by BI Pharma KG which is approved by the FDA and/all of the
         European Community regulatory authorities for commercial scale
         production and deliveries.

         To the extent that L&I Partners, L.P. requests that BI Pharma KG secure
         regulatory approval of the manufactured Product in other countries,
         then BI Pharma KG shall seek such regulatory approval of its production
         facility unless such approval would require change in the production
         facility.

         L&I Partners, L.P. shall pay any additional costs for such approval.

         If changes are required by the respective authority and if BI Pharma KG
         does not agree to make such changes at L&I Partners, L.P.'s expense,
         then L&I Partners, L.P. shall have the right to seek a third party
         manufacturer for the respective country(ies).

         BI Pharma KG shall take all commercially reasonable efforts to secure
         approval of BI Pharma KG's manufacturing facility by the FDA and the
         respective European regulatory authority and BI Pharma KG's obligations
         under Section 2.1 above are subject to such approval as the case may
         be.

2.4      SUBCONTRACTING
         BI Pharma KG will not further contract out to a third party any part of
         the manufacturing or release-testing of Product without prior written
         approval from L&I Partners, L.P., which shall not be unreasonably
         withheld.

2.5      ROLLING FORECASTS
         (1)      Beginning as of 10 September 1999 and by the 10th of the last
                  month of each quarter L&I Partners, L.P. will provide BI
                  Pharma KG with a [**] Product forecast planning horizon for
                  Final Product and Finished Product or an update thereof. The
                  planning horizon shall start the first day of the fourth month
                  after the first forecast which shall be January 2000 or an
                  update thereof.

                  The rolling forecasts are to be broken down to single months.


<PAGE>



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          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


          (2)     The forecast for the first year (months 1-12) are [**].

                  The forecast for the second year (months 13-24) is a [**]
                  forecast which means that the forecast can [**] within this
                  period as follows:

                  the forecast may be [**] within the Capacity, but is limited
                  to the following restrictions [**]:

                  months [**] the forecast can be [**]
                  months [**] the forecast can be [**]
                  months [**] the forecast can be [**]
                  months [**] the forecast can be [**]

                  The forecast for the third year (months 25-36) is a [**]
                  forecast. The rolling forecasts (including [**] orders) for
                  Final Product and Finished Product are laid down in Appendix
                  2.

         (3)      Whilst the rolling forecast system is not applicable (see
                  Article 2.5(1) above) L&I Partners, L.P. shall place all
                  requirements for Product and Final Product [**].

2.6      QUANTITIES BEYOND THE [**] FORECASTS
         BI Pharma KG shall use reasonable efforts to manufacture and deliver to
         L&I Partners, L.P. all quantities of the Product beyond the [**]
         forecasts at L&I Partners, L.P.'s request within its Capacity.

2.7      DELIVERY
         BI Pharma KG shall make deliveries by the 15th day of the month for
         which [**] order is made.

2.8      MINIMUM QUANTITIES
         Provided that the Product is approved in the USA, and starting as of
         [**], the minimum quantity of Product to be bought by L&I
         Partners, L.P. each calendar year is [**] based on the assumptions set
         forth in Appendix 1.

         If the quantity falls below the minimum quantity of [**] of Product
         annually, BI Pharma KG will charge L&I Partners, L.P. an annual
         surcharge according to Article 5.2 below.

2.9      EXCLUSIVITY/COMPETITION
         During the term of this Agreement, BI Pharma KG agrees that it will not
         supply Product to a third party nor shall BI Pharma KG assist any third
         party with respect to development or manufacture of [**], except where
         BI Pharma KG is granted marketing rights [**].


<PAGE>



L&I Partners, L.P./BI Pharma KG:  Supply Agreement                       Page: 8
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          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


3.       QUALITY/WARRANTY/LIABILITY/INDEMNIFICATION

3.1      WARRANTY/LIMITATION
         BI Pharma KG warrants that the Product to be supplied by BI Pharma KG
         hereunder corresponds to the Specifications and shall be produced
         according to current GMP standard as of the date and time of production
         and in accordance with all applicable laws, rules and regulations in
         the country where produced.

         The Product shall be delivered free and clear of liens and claims which
         affect title. BI Pharma KG makes no other warranty of any kind, express
         or implied.

3.2      TESTS OF THE PRODUCT AND AGREED UPON AUDITS
         L&I Partners, L.P. shall have the right to carry out agreed upon
         customary tests of the Product and agreed upon audits at reasonable
         times, of the premises and facilities where BI Pharma KG performs work
         under this Agreement, and of the premises where it stores raw
         materials, auxiliary materials, intermediates, packing materials for
         the Product and the Product itself. The agreed upon tests of the
         Product shall be included in Appendix 3 hereto.

3.3      DEFECTIVE PRODUCT (INCLUDING LOSS AND INACCURATE QUANTITY)
         Claims on account of quantity, quality, loss or damages to the Product
         shall be made by L&I Partners, L.P. in writing within [**] following
         receipt thereof, and BI Pharma KG's liability for damages for such
         claims shall in no event exceed the purchase price or replacement of
         goods for the particular shipment with respect to which such claims are
         made. No Product will be returned to BI Pharma KG without BI Pharma
         KG's written permission.

         If L&I Partners, L.P. claims that any shipment of Product did not at
         time of delivery meet the Specifications, BI Pharma KG shall conduct an
         assay of its retained sample from such shipment. If BI Pharma KG agrees
         with L&I Partners, L.P.'s claim, BI Pharma KG shall replace such
         shipment of Product within [**] from existing stock of released Product
         if available, and if not available, at L&I Partners, L.P.'s option, BI
         Pharma KG shall either replace such shipment of Product within [**] or
         give credit for such payment to L&I Partners, L.P. If the parties are
         unable to resolve their differences, then either party may refer the
         matter to an independent specialized firm of international reputation
         agreeable to both parties for final analysis, which shall be binding on
         both parties hereto.

3.4      INDEMNIFICATION BY L&I PARTNERS, L.P.
         In accordance with all applicable laws L&I Partners, L.P. shall be
         responsible for, and hold BI Pharma KG harmless from any damage, loss,
         cost or expense relating to third party claims or suits arising from
         the packaging, use, marketing or sale of the Product by L&I Partners,
         L.P., or its licensee(s) or other authorized persons or entities, other
         than those which arise out of a breach of warranty by BI Pharma KG and
         those which arise out of gross negligence or willful misconduct of BI
         Pharma KG or its officers, employees or agents, and provided that upon
         receipt of


<PAGE>



L&I Partners, L.P./BI Pharma KG:  Supply Agreement                       Page: 9
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          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


         notice by BI Pharma KG of any claims or suits relating to such use or
         sale of the Product, BI Pharma KG shall notify L&I Partners, L.P.
         thereof without delay and shall permit L&I Partners, L.P. to handle
         such claims or suits at the cost and discretion of L&I Partners, L.P.
         including but not limited to defense, settlement and compromise
         thereof.

3.5      INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS
         With respect to the Process, L&I Partners, L.P. shall be responsible
         for and hold BI Pharma KG harmless from any third party claim of
         infringement of its intellectual property rights from a third party
         based upon BI Pharma KG's contractual activities hereunder.

3.6      LIMITATION OF WARRANTY/LIABILITY/MAXIMUM AMOUNT
         Except as provided in Article 3.1 above, BI Pharma KG makes no warranty
         of any kind, express or implied.

         Except for willful misconduct BI Pharma KG shall not be liable for any
         lost profits or any special, incidental or consequential damages.

         BI Pharma KG's total liability under this Agreement shall in no event
         exceed [**] of the sales of Product from BI Pharma KG to L&I Partners,
         L.P. or L&I Partners, L.P.'s licensee(s) of the respective year.

3.7      DELIVERY/RISK OF LOSS
         BI Pharma KG shall deliver or arrange for the delivery of the Product
         purchased by L&I Partners, L.P. to a carrier designated by L&I
         Partners, L.P. on the basis of EXW BI Pharma KG's plant in Biberach, in
         accordance with Incoterms 1990 as published. Title to the Product sold
         hereunder shall pass to L&I Partners, L.P. and BI Pharma KG's liability
         as to risk of loss and/or damage during transportation thereof shall
         cease upon delivery of the Product in good condition to the carrier at
         BI Pharma KG's plant in Biberach designated by L&I Partners, L.P..

3.8      DOCUMENTATION
         BI Pharma KG shall certify in writing, that each shipment lot of
         Product, was produced and tested in compliance as of the time of
         production with (i) the Specifications (including the respective test
         methods), (ii) the current GMP requirements, (iii) all other applicable
         regulatory documents, in accordance with procedures agreed between BI
         Pharma KG and L&I Partners, L.P. BI Pharma KG shall provide L&I
         Partners, L.P. with a Certificate of Analysis appropriately signed and
         a Certificate of Compliance appropriately signed by BI Pharma KG's
         quality assurance, as are necessary to demonstrate BI Pharma KG 's
         compliance with this Article 3.8 for and with each shipment lot from BI
         Pharma KG 's manufacture site.



<PAGE>



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         Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.

3.9      INDEMNIFICATION BY BI PHARMA KG
         BI Pharma KG shall indemnify, defend and hold L&I Partners, L.P. and
         its officers, employees and agents harmless from and against all third
         party losses, damages, costs and expenses (including, without
         limitation, reasonable attorneys' fees), including injury to persons or
         damage to property, resulting from any breach of the warranties made by
         BI Pharma KG under this Agreement or which arise out of and are proved
         to be directly associated with the gross negligence or willful
         misconduct of BI Pharma KG or its officers, employees or agents in
         carrying the obligations under this Agreement and provided that upon
         receipt of notice by L&I Partners, L.P. of any claims or suits relating
         to such use or sale of the Product, L&I Partners, L.P. shall notify BI
         Pharma KG thereof without delay and shall permit BI Pharma KG to handle
         such claims or suits at the cost and discretion of BI Pharma KG
         including but not limited to defense, settlement and compromise
         thereof.

3.10     SUPERIORITY
         No provision on L&I Partners, L.P.'s purchase order forms or in BI
         Pharma KG's General Conditions of Sale which may purport to impose
         different conditions upon L&I Partners, L.P. or BI Pharma KG, nor any
         other modification of this Agreement, will be of any force and effect,
         unless in writing and signed by both parties claimed to be bound
         thereby. In the event of any inconsistencies the terms of this
         Agreement shall govern.

4.       SUPPORT REGARDING POST LICENSING ISSUES

         BI Pharma KG is willing to support L&I Partners, L.P. with regard to
         post licensing issues (e.g. possible registration-issues in the various
         countries) on commercial conditions to be agreed upon separately.

5.       PRICE AND PAYMENT

5.1      PRODUCT-PRICE
         The Product-price for the Product shall be calculated according to the
         scheme laid down in Appendix 1. The basic product assumptions of that
         scheme as [**] will be reassessed after scale-up of the Process to
         the commercial scale after the [**]manufacturing campaign successful
         batches and then be valid for this Agreement.

5.2      SURCHARGE
         If L&I Partners, L.P. doesn't purchase the minimum quantities of
         Product in a given year (i.e. supplied quantities are below minimum
         quantities), L&I Partners, L.P. shall pay a surcharge according to the
         scheme in Appendix 1.

5.3      PAYMENT CONDITIONS
         (1)      Premarketing Phase:

         The Product-price for Product ordered by L&I Partners, L.P. or
         according to L&I Partners, L.P.'s instructions during the premarketing
         phase shall be payable by

<PAGE>


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         Securities and Exchange Commission. Asterisks denote omissions.


         L&I Partners, L.P. within 30 (thirty) days after receipt by L&I
         Partners, L.P. of notification of release of the respective Bulk
         Product.

(2)      Marketing Phase:

         Unless otherwise provided for in Article 5.3 (1) above, the
         Product-price for Product delivered to L&I Partners, L.P. or according
         to L&I Partners, L.P.'s instructions shall be payable by L&I Partners,
         L.P. within 30 (thirty) days after receipt of Product by the respective
         party.

(3)      Surcharge:

         The surcharge according to Article 5.2 above shall be payable within 30
         (thirty) days after receipt of the respective invoice.

(4)      Invoice/Transfer of Payments:

         All invoices under this Agreement shall be made by BI Pharma KG in
         Deutsche Mark and all payments under this Agreement shall be made by
         L&I Partners, L.P. in DEM (Deutsche Mark) by wire transfer to an
         account to be nominated by BI Pharma KG.

5.4      CURRENCY/CONVERSION
         "Deutsche Mark" or "DEM" means the lawful currency for the time being
         of Germany or, in case of the implementation of the European Monetary
         Union, the "Euro" on the basis of the official conversion rate.

         Currency conversions, if any, shall be made using the average quarterly
         exchange rates published regularly by Deutsche Bank AG, Frankfurt, or
         its successor. The average will be calculated by summing the exchange
         rates for the final business day of each of the 3 (three) months in the
         applicable calendar quarter and dividing by 3 (three). All currency
         conversions will be calculated to an accuracy of at least 3 (three)
         digits after the decimal point.

5.5      PRICES ADJUSTMENTS
         (a)      The Product-price mentioned in Article 5.1 above (basis
                  14.05.1998) may be increased by BI Pharma KG effective at the
                  beginning of a calendar year (for the first time effective
                  January 1, 2000) by [**] per year for [**].


<PAGE>


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         Securities and Exchange Commission. Asterisks denote omissions.


         (b)      In case any cost increases (in terms of [**] of [**]
                  for [**] and/or [**]) by more than [**] in a given
                  calendar year, which BI Pharma KG must demonstrate, the
                  parties shall agree upon the direct amount of such
                  increase based on good faith negotiations to be effective
                  on January 1st of the calendar year following the more than
                  [**] increase and the price for Product in such calendar year
                  shall be increased for such amount, provided that the price
                  increase taken by BI Pharma KG under Article 5.5 (a) shall be
                  [**] under this Article 5.5 (b).

         (c)      In case of any cost decrease (as defined in lit. (b) above) by
                  more than [**] in a given calendar year, the parties shall
                  agree upon the direct amount of such decrease based on good
                  faith negotiations to be effective on January 1st of the
                  calendar year following the more than [**] decrease and the
                  price for Product in such calendar year shall be decreased for
                  such amount.

         (d)      In case of a change of the Process which lasting influences
                  the basic assumptions, the price shall be recalculated
                  according to Appendix 1 after [**] and the parties shall agree
                  on a new price for Product on the basis of an [**] of the
                  [**] as an [**] and BI Pharma KG shall on an ongoing basis
                  intend to provide suggestions for such enhancements of the
                  Process. Such agreed new price will then be effective for
                  Product produced with the new Process from the next run on.

         (e)      L&I Partners, L.P. may elect whether the direct amount of an
                  increase according to (a) and (b) above is payable pursuant
                  to a separate invoice or by a proportional increase in the
                  price for Bulk Product, Final Product and/or Finished
                  Product. If L&I Partners, L.P. [**] BI Pharma KG that [**]
                  for [**] can be [**] a [**] and of [**] and [**] than [**]
                  of [**], then [**] for [**] Article 5.5 (b).

5.6      INTRODUCTION OF THE EURO
         The introduction of the Euro as the legal currency or legal tender in
         Germany (see Article 5.4 above) shall in no way affect the validity of
         this Agreement and shall not entitle any party hereto to terminate, or
         to require any amendment to this Agreement.



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 13
--------------------------------------------------------------------------------


6.       CONFIDENTIALITY

6.1      BI PHARMA KG
         shall not disclose L&I Partners, L.P. Confidential Information to any
         person other than its employees or employees of affiliated companies of
         the Boehringer Ingelheim group who have a need to know such information
         in order to perform their duties in carrying out the work hereunder and
         who have an obligation to maintain the confidentiality thereof as
         provided herein without the other party's written consent.

6.2      L&I PARTNERS, L.P.
         shall not disclose any BI Pharma KG Confidential Information to any
         person other than

         (a)      its employees or consultants who are bound by 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 work, or

         (b)      regulatory authorities, for example, the FDA, that require
                  such information in order to review an IND, BLA or other
                  regulatory filing. BI Pharma KG will be informed and must
                  agree prior to filing of any BI Pharma KG Confidential
                  Information to regulatory authorities. In these cases where BI
                  Pharma KG restricts L&I Partners, L.P.'s ability to file BI
                  Pharma KG Confidential Information, BI Pharma KG agrees to
                  provide the Confidential Information directly to the
                  regulatory authorities and will provide a letter of
                  authorization for cross-reference to L&I Partners, L.P.

         (c)      persons or entities that manufacture Product for L&I Partners,
                  L.P. after termination of this Agreement or during this
                  Agreement as permitted herein without the other party's
                  written consent.

6.3      EXCEPTIONS

         The obligations of confidentiality applicable to L&I Partners, L.P.
         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;

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



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 14
--------------------------------------------------------------------------------


         (e)      required to be disclosed by law, regulation (e.g. by
                  SEC-regulation) or the order of a judicial or administrative
                  authority; or

         (f)      released with the prior written consent of the disclosing
                  party.

         (g)      released to a potential marketing partner after written notice
                  thereof to BI Pharma KG and under secrecy obligations covering
                  at least the same extent as stated herein.

7.       LICENSE

7.1      USE OF L&I PARTNERS, L.P. CELL LINE AND INTELLECTUAL PROPERTY
         L&I Partners, L.P. and BI Pharma KG hereby acknowledge and agree that
         L&I Partners, L.P. is providing Cell Line, Process and L&I Partners,
         L.P. Confidential Information to BI Pharma KG for use by BI Pharma KG
         on behalf of and for the benefit of L&I Partners, L.P. for the purposes
         of this Agreement, that BI Pharma KG will make use thereof solely for
         such purposes and that L&I Partners, L.P. hereby consents to such use.
         BI Pharma KG agrees that L&I Partners is the owner of the Cell Line,
         Process, and L&I Partners Confidential Information, and upon
         termination of this Agreement such shall be returned to L&I Partners,
         L.P., provided however, that BI Pharma KG shall have the right to
         retain one copy/sample for documentation purposes solely or if and when
         and to the extent required by law or regulation.

7.2      NO OTHER RIGHT OR LICENSE
         Except as granted under this Agreement, no right or license, either
         express or implied, under any patent or proprietary right is granted
         hereunder by virtue of the disclosure of L&I Partners, L.P.
         Confidential

         Information or BI Pharma KG Confidential Information.

8.       TERM AND TERMINATION

8.1      BASIC TERM
         This Agreement will come into force and effect as of the date first
         above written, and shall remain valid until December 31, 2006.

8.2      AUTOMATIC EXTENSION
         This Agreement will automatically extend for additional 3 (three) year
         periods in the absence of a written notice of termination by one of the
         parties to the other and such written notice shall be given no later
         than 2 (two) years prior to the end of the fix period and 3 (three)
         years prior to the end of any extension period.


<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 15
--------------------------------------------------------------------------------
          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


8.3      EARLY TERMINATION
         To the extent permitted by law, if either party shall become insolvent
         or shall make assignment for the benefit of creditors, or proceedings
         in voluntary bankruptcy shall be instituted on behalf of or against a
         party or a receiver or trustee of all, or substantially all of the
         property of a party shall be appointed to a third party, the other
         party shall be entitled to terminate this Agreement by giving written
         notice to this effect to the first party whereupon this Agreement shall
         so terminate, unless such situation is rectified within a period of 60
         (sixty) days.

8.4      TERMINATION IN CASE OF BREACH OF AGREEMENT
         Either party may terminate this Agreement for any material breach of
         this Agreement, if such breach is not cured within 90 (ninety) days
         following receipt by the party committing the breach of written notice
         of the intent to terminate. Such termination shall become effective
         immediately upon further notice to the defaulting party.

8.5      PREMATURE TERMINATION
8.5.1    This Agreement may be terminated by L&I Partners, L.P. at any time if
         L&I Partners, L.P. shall withdraw the Product from all relevant markets
         (US, Canadian and Europe).

8.5.2    In this case L&I Partners, L.P. will pay to BI Pharma KG the
         Product-price for the [**]ordered quantities (see Article 2.5 above) of
         the Product.

8.5.3    Moreover, L&I Partners, L.P. will pay to BI Pharma KG an amount to
         cover the production loss caused by the premature termination as
         follows:

         for the 2 (two) years following the [**] order period (which is year 1)
         L&I Partners, L.P. will pay the Product price for the minimum quantity
         (according to Article 2.8 above) [**]

         [**] for year 2
         [**] for year 3.

8.5.4    Due Date

         These payments shall be due within 1 (one) month after receipt by BI
         Pharma KG of the notice of premature termination from L&I Partners,
         L.P. and receipt by L&I Partners, L.P. of the respective invoice of BI
         Pharma KG.

9.       MISCELLANEOUS

9.1      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 due hereunder) occasioned by any act of God, fire, act of
         government or state, war,



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 16
--------------------------------------------------------------------------------


         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; provided,
         however, that if a party is not able to perform because of a force
         majeure pursuant to this Article 8.1 for a period of 6 (six) months,
         the other party may terminate this Agreement with immediate effect. In
         this case the provisions of Article 8.5.3 shall not apply.

9.2      PUBLICITY

         No press release or other form of publicity regarding the work
         performed hereunder or this Agreement shall be permitted by either
         party to be published unless both parties have indicated their consent
         to the form of the release in writing.

         Nothing in this Article 9.2 shall prevent the parties from disclosing
         this Agreement as required by applicable laws, rules or regulations.

9.3      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, (iii)
         delivered by facsimile with immediate telephonic confirmation of
         receipt, to the addresses or facsimile numbers set forth below or (iv)
         sent by overnight carrier (such as Federal Express, UPS, DHL, MSAS,
         World Courier):



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 17
--------------------------------------------------------------------------------


If to BI Pharma KG:                 Boehringer Ingelheim Pharma KG
                                    Birkendorfer StraBe 65
                                    D-88397 Biberach an der Riss
                                    Federal Republic of Germany
                                    Attention: Dr. Wolfram Carius
                                    Fax:  0 73 51/54 - 9 80 49
                                    Phone:  0 73 51/54 - 94 21

If to L&I Partners, L.P.:           LeukoSite Inc.
                                    215 First Street
                                    Cambridge, MA 02142
                                    Attention: President and CEO
                                    Fax:  617/621 93 49
                                    Phone:  617/621 93 50
                                    with a copy to
                                    Chief Financial Officer and/or
                                    Vice President Manufacturing
                                    at the same address

         Each notice shall be deemed given (i) on the date it is received if it
         is delivered personally, (ii) 3 (three) days after the date it is sent
         by Federal Express, UPS, DHL, MSAS, World Courier or similar service if
         receipt is immediately confirmed in writing (iii) on the date it is
         received if it is sent by facsimile with immediate telephonic
         confirmation of receipt.

9.4      APPLICABLE LAW/JURISDICTION
         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
         jurisdiction over all legal matters and proceedings hereunder.

         In case of any dispute, claim or controversy arising out of or relating
         to the interpretation, execution or performance of this Agreement the
         parties shall first try to settle the matter amicably, possibly by
         having recourse to a neutral person acceptable to both parties.

9.5      COMPLIANCE WITH LAWS
         BI Pharma KG shall perform the work hereunder in conformance with
         current GMP, at the time of the respective production, as applicable,
         and all German and/or EEC laws, ordinances and governmental rules or
         regulations pertaining thereto.


<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 18
--------------------------------------------------------------------------------


9.6      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 ventures, 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.

9.7      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.

9.8      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 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.

9.9      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
         they are hereafter made in writing and signed by both parties.

9.10     ASSIGNMENT
         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 provided always that
         nothing herein shall permit any assignment by either party.

         However, BI Pharma KG may assign this Agreement to an affiliated
         company taking over the operative biotech business of BI Pharma KG and
         L&I Partners, L.P. may assign this Agreement in the case of a merger or
         acquisition or transfer of its assets related to this Agreement to a
         third party without the prior written consent of BI Pharma KG.



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 19
--------------------------------------------------------------------------------


IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed
by their duly authorized representatives on the day and year first above
written.

Cambridge JUNE 4, 1999                          Biberach, MAY 5TH, 1999
          ------------                                    -------------
L&I PARTNERS, L.P., INC.                        BOEHRINGER INGELHEIM PHARMA KG
                                                                           ppa.

<TABLE>
<S>                                             <C>                       <C>

         [Illegible]                            /s/ Dr. Deter Jacob       /s/ Prof. Dr. Rolf G. Werner
------------------------------------            -------------------       ----------------------------
                                                Dr. Deter Jacob           Prof. Dr. Rolf G. Werner
                                                (Member of the Board)     (Head of Biotech worldwide)
</TABLE>



<PAGE>


L&I Partners, L.P./BI Pharma KG:  Supply Agreement                      Page: 20
--------------------------------------------------------------------------------


APPENDICES

<TABLE>

<S>               <C>

Appendix 1:       Product-price and basic product assumptions

Appendix 2:       Rolling forecast for Final Product and Finished Product

Appendix 3:       Specifications for Product including tests

Appendix 4:       Process Description

Appendix 5:       Agreed upon stock policy of the Parties

Appendix 6:       Agreed upon format of "Certificate of Compliance"
</TABLE>


<PAGE>

          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


                                                                      APPENDIX 1

                         MASTER PROJECTPLAN : CAMPATH-1H
                          L & I PARTNERS / BI PHARMA KG

      Basic Production Assumptions and Pricing System for Commercial Supply

PRODUCTION ASSUMPTIONS:

                  [**]

         Total material amount [**]

                                    SUPPLY QUANTITY PER YEAR      PRICE PER GRAM

                                                       [**]              [**]

PRICE FOR STERILE LIQUID FILLING FOR COMMERCIAL SUPPLY

         BATCH SIZE [**]                                                 [**]
         [**]

         BATCH SIZE [**]
         [**]                                                            [**]

PRICE FOR LABELING AND PACKAGING FOR COMMERCIAL SUPPLY

                  [**]                                                   [**]
*)S = SURCHARGE

         The surcharge system is effective, [**]

PRICE CALCULATION FINISHED PRODUCT

         [**]



<PAGE>


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


                                                                     APPENDIX 2a

Example for firm order in pre approval phase

                ORDER PLANNING SYSTEM OF CAMPATH-1H FINAL PRODUCT
                       COMMERCIAL SUPPLY PRE FDA APPROVAL





                                      [**]



<PAGE>


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.



                                                                     APPENDIX 2b


                ROLLING FORECAST PLANNING SYSTEM OF FINAL PRODUCT
                         CAMPATH-1H (COMMERCIAL SUPPLY)
                                POST FDA APPROVAL







                                      [**]



<PAGE>


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


                                                                      APPENDIX 3
                                                                   (Page 1 of 2)



SPECIFICATIONS FOR PRODUCT CAMPATH 1H
INCLUDING TESTS



TABLE 1  SPECIFICATIONS FOR BULK DRUG SUBSTANCE**





                                      [**]





<PAGE>


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


                                                                      APPENDIX 3
                                                                   (Page 2 of 2)

TABLE 2  SPECIFICATIONS FOR DRUG PRODUCT RELEASE

                                                       [**]





<PAGE>


          Confidential Materials omitted and filed separately with the
         Securities and Exchange Commission. Asterisks denote omissions.


                                                                      APPENDIX 4

DESCRIPTION OF THE PROCESS

The Process for manufacturing Product as agreed upon by the Parties is described
in detail in Section 4.2.3.3., "Description of the Manufacturing Process" of the
BLA (Biologics License Application) as first submitted to the FDA.


<PAGE>


                                                                      APPENDIX 5

(Section 2.1 of the Supply Agreement on Campath-1H)

              SAFETY STOCK POLICY

              Drug Product, Finished Product [**]
              Bulk Drug Substance [**]
              Raw material [**]


   The safety stock quantity is calculated based on the given [**] product
                 request and should ensure a high service level

  The safety stocks are built up [**] with respect to the shelf life of
         the product and manufacturing flexibility.


<PAGE>


                                                                      APPENDIX 6

Agreed upon format of "Certificate of Compliance"

See Attachment


<PAGE>


                                                                      APPENDIX 6

Boehringer
Ingelheim                  CERTIFICATE OF COMPLIANCE


_______________________________________________________________________________


Product:


_______________________________________________________________________________


Lot No.:


_______________________________________________________________________________


Manufacturing Date:
Expiration Date:        ___________________

Number of ampoules:



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


It is hereby certified that all manufacturing documents including batch
manufacturing records and in-process control sheets have been inspected and
found to be in compliance with current specifications and that the analyses
carried out in our control laboratory have revealed the results of the
attached analytical certificates and are in compliance with current
specifications.

If occurred, deviations during manufacturing and testing of the product are
documented in the batch manufacturing and testing records and have been
assessed and found to be acceptable.

The batch was manufactured in accordance with cGMP's and with the product's
BLA.

The lot is approved and released.

BOEHRINGER INGELHEIM PHARMA KG

QUALITY ASSURANCE

Signature:
                  --------------------------------


Date:

                  --------------------------------
                              (day/month/year)