<PAGE>
 
                                                                  EXHIBIT 10.34











                            ASSET PURCHASE AGREEMENT

                             dated February 11, 1998

                                     between

                            ROCHE HEALTHCARE LIMITED

                                       and

                                 CENTOCOR, INC.
<PAGE>
 
                                TABLE OF CONTENTS

<TABLE> 

<S>  <C>                                                                                    <C> 
1.   DEFINITIONS............................................................................2

2.   ASSETS BEING SOLD......................................................................6
     2.1.     Patents.......................................................................6
     2.2.     Licenced Patents..............................................................7
     2.3.     Patent Applications...........................................................7
     2.4.     Fujisawa Patent Licence.......................................................8
     2.5.     Trademarks....................................................................8
     2.6.     Registrations.................................................................8
     2.7.     Manufacturing Technology and Know-How.........................................9
     2.8.     Research and Development Materials............................................9
     2.9.     Clinical Data................................................................10
     2.10.    World-wide Safety Reports....................................................10
     2.11.    Marketing and Promotional Documents..........................................10
     2.12.    Inventory....................................................................10
     2.13.    Assumed Agreements...........................................................11
     2.14.    Other Assets.................................................................11
     2.15.    Tangible Assets..............................................................11
     2.16.    Non-exclusive Licences.......................................................11
     2.17.    Limitation of Sale of Assets.................................................12

3.   PURCHASE PRICE........................................................................12
     3.1.     Purchase Price...............................................................12
     3.2.     Allocation of Purchase Price.................................................12
     3.3.     Payment for Inventory........................................................12
     3.4.     Refund of Purchase Price.....................................................13
     3.5.     Royalty Payments.............................................................14

4.   REPRESENTATIONS AND WARRANTIES OF PARENT..............................................17
     4.1.     Organisation.................................................................17
     4.2.     Authority....................................................................17
     4.3.     No Violation or Conflict.....................................................17
     4.4.     No Government Restrictions...................................................17
     4.5.     Title to Assets..............................................................17
     4.6.     Patents......................................................................18
     4.7.     Trademarks...................................................................18
     4.8.     Registrations................................................................18
     4.9.     Know-How and Know-How Licence................................................19
     4.10.    Inventory....................................................................19
     4.11.    Taxes........................................................................19
</TABLE> 
<PAGE>
 
<TABLE> 
<S>  <C>      <C>                                                                          <C> 
     4.12.    Absence of Certain Changes...................................................19
     4.13.    Violations of Law............................................................19
     4.14.    Financial Information........................................................19
     4.15.    Litigation...................................................................20
     4.16.    Sufficiency of Assets........................................................20
     4.17.    Conduct of Business..........................................................20
     4.18.    Retavase Business............................................................21

5.   REPRESENTATIONS AND WARRANTIES OF BUYER...............................................21
     5.1.     Organisation.................................................................21
     5.2.     Authority....................................................................21
     5.3.     No Violation or Conflict.....................................................21
     5.4.     No Government Restrictions...................................................21
     5.5.     Litigation...................................................................21
     5.6.     Financing....................................................................22
     5.7.     Assets.......................................................................22

6.   PARENT'S COVENANTS....................................................................22
     6.1.     Maintenance of Assets/Conduct of Business....................................22
     6.2.     Compliance with Laws.........................................................23
     6.3.     Access.......................................................................23
     6.4.     Patent Maintenance and Defence...............................................23
     6.5.     Sale of Retavase by the Roche Group..........................................24
     6.6.     Sales Force..................................................................24
     6.7.     Further Assurances...........................................................24
     6.8.     Nonassertion.................................................................25
     6.9.     Genentech Disclosure.........................................................25
     6.10.    Control of Genentech, Inc....................................................25
     6.11.    Keep Well Agreement..........................................................26

7.   BUYER'S COVENANTS.....................................................................26
     7.1.     Approvals and Registrations for Transfer of Distribution of
              Products.....................................................................26
     7.2.     Labelling....................................................................26
     7.3.     References to Parent.........................................................27
     7.4.     Further Assurances...........................................................27
     7.5.     Financing....................................................................27
     7.6.     Notification.................................................................27
</TABLE> 




                                      ii
<PAGE>
 
<TABLE> 
<S>  <C>      <C>                                                                          <C> 
8.   COVENANTS BY BUYER AND PARENT.........................................................28
     8.1.     Assignment of Patents and Trademarks.........................................28
     8.2.     Assignment of Registrations..................................................28
     8.3.     Clinical Studies Transfer....................................................29
     8.4.     Access to Information........................................................29
     8.5.     Press Releases...............................................................29
     8.6.     Customer Information.........................................................30
     8.7.     Hospital and Other Purchasing Contracts......................................30
     8.8.     Reconciliation with the Agreement Containing Consent
              Order; Canadian Filings......................................................30
     8.9.     Genentech Patent Suits.......................................................30
     8.10.    Transition Services..........................................................32
     8.11.    Returns......................................................................32
     8.12.    Chargebacks and Rebates......................................................32
     8.13.    Confidentiality..............................................................32
     8.14.    Consents.....................................................................32
     8.15.    Cooperation on Safety Reports................................................32
     8.16.    Manufacturing Improvements...................................................32
     8.17.    Importation..................................................................33
     8.18.    Product Recall; Product Liability............................................33

9.   MANUFACTURING.........................................................................33
     9.1.     Supply Agreement.............................................................33
     9.2.     Parent's Representations and Warranties for its Supplies.....................33
     9.3.     Technology Transfer..........................................................34
     9.4.     Approvals....................................................................34

10.  CONDITIONS PRECEDENT TO CLOSING.......................................................35
     10.1.    Conditions to Obligations of Buyer and Parent................................35
     10.2.    Conditions to Obligations of Buyer...........................................36
     10.3.    Conditions to Obligations of Parent..........................................36

11.  THE CLOSING...........................................................................37
     11.1.    The Closing..................................................................37
     11.2.    Deliveries by Parent.........................................................37
     11.3.    Deliveries by Buyer..........................................................38
     11.4.    Effects of Closing...........................................................38
</TABLE> 





                                      iii
<PAGE>
 
<TABLE> 
<S>  <C>       <C>                                                                         <C> 
12.  TERMINATION...........................................................................39
     12.1.    Termination..................................................................39
     12.2.    Effect of Termination........................................................40
     12.3.    Termination by the FTC.......................................................40

13.  SURVIVAL; REMEDIES; CLAIMS; INDEMNIFICATION...........................................41
     13.1.    Remedy for Breach............................................................41
     13.2.    Indemnification by Parent....................................................41
     13.3.    Indemnification by Buyer.....................................................42
     13.4.    Notice.......................................................................42
     13.5.    Participation in Defence.....................................................42
     13.6.    Settlements..................................................................43
     13.7.    Other Claims.................................................................43

14.  NOTICES...............................................................................44

15.  ARBITRATION AND GOVERNING LAW.........................................................45

16.  ADDITIONAL TERMS......................................................................45
     16.1.    Brokers......................................................................45
     16.2.    Expenses, Taxes and Fees.....................................................46
     16.3.    Entire Agreement.............................................................46
     16.4.    Successors and Assigns.......................................................46
     16.5.    Amendments; No Waiver........................................................46
     16.6.    Counterparts.................................................................46
     16.7.    Captions.....................................................................46
</TABLE> 



                                      iv
<PAGE>
 
                            ASSET PURCHASE AGREEMENT


         This ASSET PURCHASE AGREEMENT (this "Agreement") is made and entered
into on February 11, 1998 by and between Roche Healthcare Limited, Hamilton,
Bermuda ("Parent") and Centocor, Inc., a Pennsylvania corporation
("Buyer").

         Whereas Parent entered into a Stock Purchase Agreement (the "Stock
Purchase Agreement") dated 24 May 1997 with the owners of Corange Limited,
Hamilton, Bermuda ("Corange") providing for the acquisition by Parent of all
shares of Corange (the "Corange Transaction"), which among other things owns the
BM Group (as hereinafter defined);

         Whereas, pursuant to an Agreement Containing Consent Order to be
entered into by Parent with the Federal Trade Commission (the "FTC") in order to
permit consummation of the Corange Transaction, a copy of which will be provided
to Buyer as soon as accepted by the FTC, Parent will be required to cause BM
Group companies to divest RETAVASE in the United States and Canada;

         Whereas the Corange Transaction is further subject to the approval of
other merger control authorities, including the Director of Investigation and
Research in Canada (the "Director") appointed under the Competition Act (Canada)
as well as approval under the Investment Canada Act, if required;

         Whereas, Buyer desires to purchase the Assets (as defined below) from
the BM Group companies and Parent desires to cause Sellers (as hereinafter
defined) to sell the Assets to Buyer, upon the terms and subject to the
conditions hereinafter set forth;

         Now, therefore, in consideration of the foregoing and of the mutual
promises, covenants, representations, warranties and agreements contained
herein, and intending to be legally bound, the parties hereto agree as follows:
<PAGE>
 
1.       DEFINITIONS

              1.1.   "Active Ingredient" means recombinant reteplase; (rPA), a
         recombinant, nonglycosylated plasminogen activator, containing amino
         acids 1-3 and 176-527 of the amino acid sequence of the tissue-type
         plasminogen activator.

              1.2.   "Affiliate" of an entity means any corporation or other
         business entity controlled by, controlling or under common control
         with, such entity. For this purpose "control" shall mean direct or
         indirect beneficial ownership of more than fifty percent (50%) of the
         voting or income interest in such corporation or other business entity;
         provided, however, Genentech, Inc. and its subsidiaries shall not be
         considered an Affiliate of Parent.

              1.3.   "Assets" has the meaning ascribed to such term in 
         Section 2.

              1.4.   "Assumed Agreements" has the meaning ascribed to such
         term in Section 2.13.

              1.5.   "best of Parent's knowledge" means the best knowledge of
         Parent and Sellers.

              1.6.   "BM" means Boehringer Mannheim GmbH, Mannheim, Germany.

              1.7.   "BMC" means Boehringer Mannheim Corporation, Indianapolis,
         Indiana, USA.

              1.8.   "BM Canada" means Boehringer Mannheim Ltd., Laval, Quebec,
         Canada.

              1.9.   "BM Group" means BM, BMC and BM Canada and any Affiliates
         of such companies, and any other company in the Boehringer Mannheim
         group involved in the Business.

              1.10.  "BM Labelling" means the printed labels, labelling and
         packaging materials, including printed carton, container label and
         package inserts, as currently used by BMC or its Affiliates or
         promotion partners for the Product in the Territory.

              1.11.  "BM Monthly Sales Statements" means the BM Net Sales by
         Product (including units) in the Territory in local currency, on a
         monthly

                                       2
<PAGE>
 
         basis for each month beginning with January 1997 until the end of the
         month in which Closing occurs.

              1.12.  "BM Net Sales" means gross sales of BMC of the Product in
         the Territory after deduction of returns, sales rebates (price
         reduction) and volume (quantity) discount as well as sales taxes (e.g.,
         value added taxes) and other taxes directly linked to the sales (e.g.,
         excise taxes).

              1.13.  "Business" means the business as conducted at the Closing
         Date by Sellers with respect to the Product, whether approved for sale
         or in research or development, in the Territory. "Retavase Business"
         means the business with respect to each presentation of any
         pharmaceutical preparation (including future formulation changes and
         production intermediates) containing the Active Ingredient, whether
         approved for sale or in research or development in the Territory.

              1.14.  "Clinical Data" has the meaning ascribed to such term in
         Section 2.9.

              1.15.  "Closing" has the meaning ascribed to such term in 
         Section 11.1.

              1.16.  "Closing Date" has the meaning ascribed to such term in
         Section 11.1.

              1.17.  "Damages" has the meaning ascribed to such term in Section
         13.2.1.

              1.18.  "DHC" means Department of Health Canada.

              1.19.  "Disclosure Schedule" means the disclosure schedule
         delivered as of the date hereof to Buyer by Parent in connection with
         this Agreement. The sections of the Disclosure Schedule correspond to
         the sections of this Agreement, but information disclosed in any
         section of the Disclosure Schedule shall be deemed to be disclosed as
         to all relevant sections thereof, except as otherwise specifically
         provided herein.

              1.20.  "DPM Agreement" has the meaning ascribed to such term in
         Section 2.13.

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

                                       3
<PAGE>
 
              1.22.  "FTC" means the United States Federal Trade Commission.

              1.23.  "Genentech Patent Suits" means (a) with respect to the
         United States the patent infringement suit against BM filed by
         Genentech, Inc. in the United States District Court for the District of
         Massachusetts (Judge Saris) based on the Genentech patents USP
         5,221,619 (Itakura), USP 4,342,832 (Goeddel and Heyneker), USP
         4,511,502 (Builder), USP 5,185,259 (Goeddel, Kohr) and USP 5,034,225
         (Bennett); and (b) with respect to Germany (i) the patent infringement
         suit versus BM filed by Genentech, Inc. and Boehringer Ingelheim
         International GmbH in the District Court (Landgericht) of Dusseldorf
         ([docket number] 4 O 178/96) in May 1996 based on the patent EP 0 093
         619 (Goeddel Patent) and (ii) the extension filed versus BM by
         Genentech, Inc. and Boehringer Ingelheim International GmbH in the
         District Court (Landgericht) of Dusseldorf ([docket number] 4 O 25/97)
         in November 1996 including the patent EP 0 217 379 (Mochida Patent) and
         the patent EP 0 228 862 (Bennett Patent), (iii) the nullity suit versus
         the patent EP 0 093 619 (Goeddel Patent) filed by BM in October 1996 in
         the German Federal Patent Court in Munich, (iv) the nullity suit versus
         the patent EP 0 217 379 (Mochida Patent) filed by BM in the German
         Federal Patent Court in January 1997 and (v) the appeal of BM filed 7
         September 1995 versus the decision of the European Patent Agency (EPA)
         on BM's opposition against the European Patent 0 228 862 (Bennett).

               1.24.  "HSR Act" means the Hart-Scott-Rodino Antitrust
         Improvement Act of 1976, as amended.

               1.25.  "Indemnifiable Claims" has the meaning ascribed to such
         term in Section 13.2.1 and 13.3.

               1.26.  "Indemnified Party" has the meaning ascribed to such term
         in Section 13.4.

               1.27.  "Indemnifying Party" has the meaning ascribed to such term
         in Section 13.4.

               1.28.  "Inventory" has the meaning ascribed to such term in
         Section 2.12.

               1.29.  "Keep Well" has the meaning ascribed to such term in
         Section 6.11.

                                       4
<PAGE>
 
              1.30.   "Know-How" and "Know-How Licence" have the meanings
         ascribed to such terms in Section 2.7.

              1.31.   "Licenced Patent Applications" has the meaning ascribed to
         such term in Section 2.3.

              1.32.   "Licenced Patents" has the meaning ascribed to such term
         in Section 2.2.

              1.33.   "Marketing and Promotional Documents" has the meaning
         ascribed to such term in Section 2.11.

              1.34.   "Material Adverse Effect" means a material adverse effect
         on the Assets and the Business taken as a whole.

              1.35.   "Morgan Stanley" has the meaning ascribed to such term in
         Section 5.6.

              1.36.   "Patents" has the meaning ascribed to such term in
         Section 2.1.

              1.37.   "PCI Agreement" has the meaning ascribed to such term in
         Section 2.13.

              1.38.   "Product" means each presentation of any pharmaceutical
         preparation (including formulation changes and production
         intermediates) containing the Active Ingredient, whether registered,
         marketed or in development by Sellers, as of the Closing Date.

              1.39.   "Purchase Price" means such term as used in Section 3.

              1.40.   "Registrations" has the meaning ascribed to such term in
         Section 2.6.

              1.41.   "Research and Development Materials Licence" has the
         meaning ascribed to such term in Section 2.8.

              1.42.   "Roche Group" means Roche Holding Ltd, a Swiss
         corporation, and its Affiliates (excluding Genentech, Inc. and
         subsidiaries thereof).

              1.43.   "Supply Agreement" means the agreement referred to in
         Section 9.1.

                                       5
<PAGE>
 
              1.44.   "Territory" means the United States of America and Canada
         and their respective possessions or territories.

              1.45.   "Trademarks" has the meaning ascribed to such term in
         Section 2.5.

              1.46.   "Transition Services Agreement" has the meaning ascribed
         to such term in Section 8.10.

              1.47.   "World-wide Safety Reports" has the meaning ascribed to
         such term in Section 2.10.

2.       ASSETS BEING SOLD

              Subject to Section 2.17 and the other terms and conditions of
         this Agreement, at Closing, Parent shall cause the relevant companies
         of the BM Group to be designated (collectively, the "Sellers") to sell,
         transfer, assign, licence or sublicence, as specified below, to Buyer
         and to deliver to Buyer the assets listed below (the "Assets"), and
         Buyer shall assume all the rights, titles and interest in the Assets
         and all obligations and responsibilities associated therewith as stated
         in this Agreement; provided, however, that except as specifically
         stated herein, Buyer shall not assume any liabilities, contingent or
         otherwise, arising out of or related to the conduct of the Business
         prior to the Closing Date.

              It is intended by the parties that the sale, transfer, assignment,
         conveyance, delivery or licence or sublicence to Buyer pursuant to this
         Agreement of all assets and rights of Sellers relating to the Business
         shall, together with the Supply Agreement, the Transition Services
         Agreement and Buyer's own resources, permit Buyer as of the Closing
         Date to conduct the Retavase Business in the same manner as is
         currently conducted by Sellers.

              Prior to Closing, Buyer may designate one or more Affiliates of
         Buyer to which the Assets shall be transferred at Closing by Sellers.

              At Closing, Parent shall cause the following to occur:

              2.1.   Patents. Sellers shall sell, transfer, assign, convey and
         deliver to Buyer all of Sellers' rights, title and interest in the
         patents and patent rights set forth in Schedule 2.1 hereto (the
         "Patents"), and patents of addition, re-examinations, reissues,
         extensions, granted supplementary

                                       6
<PAGE>
 
         protection certificates, substitutions, confirmations, registrations,
         revalidations, revisions, additions and the like, of or to said patents
         and patent rights and any and all continuations and
         continuations-in-part.

              2.2.   Licenced Patents. Sellers shall grant and deliver to Buyer
         a perpetual, paid-up, irrevocable, royalty-free, unlimited (other than
         as provided in this Agreement) licence for the Territory under the
         patents set forth in Schedule 2.2 hereto (the "Licenced Patents"), with
         the right to sublicence; such licence (and any sublicence thereunder)
         shall be exclusive for use in the Retavase Business (or outside the
         Territory solely and exclusively with respect to the manufacture of, or
         research, development, or the conduct of clinical trials with respect
         to, the Active Ingredient or the Product for sale in the Territory),
         and the Roche Group (including without limitation the BM Group
         companies) shall not retain any right to use or licence such Licenced
         Patents for use in the Retavase Business. Except for use in the
         Retavase Business and as set forth in Section 2.16, the Roche Group
         (including without limitation the BM Group companies) retains, and is
         not transferring hereunder, the exclusive right to use or to licence
         such patents for use with any other products in or outside the
         Territory as well as for the Active Ingredient or the Product outside
         the Territory.

              2.3.   Patent Applications.

            2.3.1.   Sellers shall grant and deliver to Buyer a perpetual, paid-
         up, irrevocable, royalty-free, unlimited (other than as provided in
         this Agreement) licence for the Territory under the patent applications
         set forth in Schedule 2.3 hereto (the "Licenced Patent Applications"),
         and any and all divisions, continuations and continuations-in-part,
         with the right to sublicence, such licence (and any sublicence
         thereunder) shall be exclusive for use in the Retavase Business (or
         outside the Territory solely and exclusively with respect to the
         manufacture of, or research, development or the conduct of clinical
         trials with respect to, the Active Ingredient or the Product for sale
         in the Territory), and the Roche Group (including without limitation
         the BM Group companies) shall not retain any right to use or licence
         such Licenced Patent Applications for use in the Retavase Business.
         Except for use in the Retavase Business and as set forth in Section
         2.16, the Roche Group (including without limitation the BM Group
         companies) retains, and is not transferring hereunder, the exclusive
         right to use or to licence such patent applications and patents that
         may result therefrom for use with any other products in or outside the
         Territory as well as for the Active Ingredient or the Product outside
         the Territory.

                                       7
<PAGE>
 
              2.3.2.  If based on a Licenced Patent Application a patent should
         issue which is solely used in the Retavase Business, Parent shall
         inform Buyer when a notice of allowance is issued and such patent shall
         be assigned to and assumed by Buyer in accordance with the principles
         set forth in Section 8.1 below.

              2.4.    Fujisawa Patent Licence. BM shall assign or sublicence to
         Buyer the Licence Agreement between Fujisawa Pharmaceutical Co., Ltd.,
         Osaka, Japan, and Boehringer Mannheim GmbH, Mannheim, Germany, dated 9
         September 1997/15 September 1997, relating to the Business ("Fujisawa
         Patent Licence") and Buyer shall, in the event of an assignment, assume
         the Fujisawa Patent Licence. In the event that after good faith
         negotiations among Parent, Buyer and Fujisawa, the parties agree that
         Buyer, upon assumption of the Fujisawa Patent Licence, will pay a
         licence fee in excess of 3%, Parent agrees that it will pay for any
         such fee in excess of 3%. In connection with the payment by Parent of
         any fee pursuant to this provision, Parent shall ensure that it does
         not obtain any confidential information from Buyer.

              2.5.    Trademarks. Sellers shall sell, transfer, assign, convey
         and deliver to Buyer all of Sellers' rights, title and interest in the
         trademark/service mark applications for the Business, which are set
         forth on Schedule 2.5 (the "Trademarks"), together with the pertaining
         documents, such as registration and renewal confirmations, trademark
         agreements and consent letters, etc. "Trademarks" also includes any
         copyrights and any unregistered trade dress that are owned by Sellers
         which are associated solely with the Business and (only as to trade
         dress) currently used on or in association with the Business.
         "Trademarks" shall not include copyrights and trade dress associated
         with the divisions, companies or corporate entities of Parent, BM Group
         or their Affiliates or distributors. "Trademarks" also does not include
         copyrights and trade dress associated with the Product and also
         associated with products not being transferred to Buyer.

              2.6.    Registrations. Sellers shall sell, transfer, assign,
         convey and deliver to Buyer all of Sellers' rights, title and interest
         in the regulatory files and approvals, registrations and governmental
         authorisations, PLAs (product licence applications), DINs, compliance
         notices, licences and permits, and any applications to the FDA or the
         comparable Canadian body or bodies pending at the Closing Date,
         contractual rights, materials and information relating to FDA and other
         government or regulatory approvals, all of which relate to the Business
         and that are held by Sellers,

                                       8
<PAGE>
 
    which are set forth on Schedule 2.6 as well as the information contained
    therein (the "Registrations").

         2.7. Manufacturing Technology and Know-How. Sellers shall sell,
    transfer and deliver to Buyer the ownership and beneficial interest of BM in
    all BM manufacturing technology and know-how and trade secrets that is
    solely and exclusively used in the Business, all as set forth in Schedule
    2.7 (the "Know-How"); and a perpetual, paid-up, irrevocable, royalty-free
    licence, with right to sub-licence, to use any manufacturing technology and
    know-how that are used in the Retavase Business (or outside the Territory
    solely and exclusively with respect to the manufacture of the Active
    Ingredient or the Product (or a future formulation of the Product) for sale
    in the Territory) (but not exclusively used thereto or usable for other
    purposes as well) (the "Know-How Licence"); such licence (and any sublicence
    thereunder) shall be exclusive for use in the Retavase Business, and the
    Roche Group (including without limitation the BM Group companies) shall not
    retain any right to use or licence such know-how for use in the Retavase
    Business. Except as set forth in Section 2.16, the Roche Group (including
    without limitation the BM Group companies) retains, and is not transferring
    hereunder, the exclusive right to use or to licence such licenced
    manufacturing technology and know-how for use with any other products in or
    outside the Territory as well as for the Active Ingredient or the Product
    outside the Territory. The parties hereby acknowledge and agree that Know-
    How shall not include, and any limitation in the Know-How Licence shall not
    be binding on Buyer as to, any information Buyer can demonstrate (i) was in
    the public domain prior to the date of this Agreement or thereafter enters
    the public domain through no fault of Buyer, its affiliates or their
    respective representatives, (ii) was available to Buyer on a non-
    confidential basis prior to its disclosure to Buyer by Parent, Sellers,
    their affiliates or their respective representatives, (iii) is later
    lawfully acquired by Buyer from sources other than Parent, Sellers, their
    affiliates or their respective representatives who are not, to the best of
    knowledge of Buyer, subject to any legally binding obligation to keep such
    information confidential, or (iv) independently developed by Buyer without
    reference to the Know-How or Know-How Licence.

         2.8. Research and Development Materials. Sellers shall sell, transfer
    and deliver to Buyer copies of all the BM research and development reports
    existing as of the Closing Date which relate to the Business, a list of
    which is set forth on Schedule 2.8, and shall grant and deliver to Buyer a
    perpetual, paid-up, irrevocable, royalty-free licence, with a right to sub-
    licence, to use any such materials in the Retavase

                                       9
<PAGE>
 
    Business (the "Research and Development Materials Licence"). Such licence
    shall be exclusive for use in the Retavase Business (or outside the
    Territory solely and exclusively with respect to the manufacture of, or the
    conduct of clinical trials with respect to, the Active Ingredient or the
    Product in the Territory), and the Roche Group (including without limitation
    the BM Group companies) shall not retain any right to use or licence such
    materials for use in the Retavase Business. Except as set forth under
    Section 2.16, the Roche Group (including without limitation the BM Group
    companies) retains, and is not transferring hereunder, the exclusive right
    to use or to licence such materials for use with any other products in or
    outside the Territory as well as for the Active Ingredient or the Product
    outside the Territory.

         2.9. Clinical Data. Sellers shall sell, transfer and deliver to Buyer a
    copy of all Clinical Data contained in Seller's clinical databases referring
    to the Active Ingredient or the Product in the form of the SAS data sets
    (the "Clinical Data").

        2.10. World-wide Safety Reports. Sellers shall sell, transfer and
    deliver to Buyer a hard copy and an electronic copy in the form existing as
    of the Closing Date of all world-wide safety reports of BM and its
    Affiliates with respect to the Active Ingredient or the Product existing as
    of the Closing Date (the "World-wide Safety Reports").

        2.11. Marketing and Promotional Documents. Sellers shall sell, transfer
    and deliver to Buyer all hard copies and electronic copies existing as of
    the Closing Date of the marketing and promotional documents owned by
    Sellers, such as customer lists, marketing and promotional plans, documents
    and materials, field force training manuals and materials, and placebo or
    demonstration kits that are exclusively used in the Business (the "Marketing
    and Promotional Documents"). All such documents shall be shipped FOB
    Sellers' location. To the extent documents exist which contain marketing and
    promotional materials relating both to the Product in the Territory and to
    other products or the Product outside the Territory, Sellers shall transfer
    and not retain all portions of such documents relating to the Product in the
    Territory to Buyer.

        2.12. Inventory. Sellers shall sell, transfer and deliver to Buyer all
    inventory consisting of Product (including samples and placebo kits), that
    are owned by Sellers for the Territory and that have been approved or are
    subsequently approved as meeting specifications, have a minimum of 12 months
    of expiration dating and are otherwise saleable in the ordinary and normal
    course of business as of the Closing Date (the "Inventory"), the

                                      10
<PAGE>
 
    prices of which are set forth on Schedule 2.12(a) hereto; the location of
    which are set forth on Schedule 2.12(b); the quantity of which shall be set
    forth in a document delivered by Parent at Closing.

        2.13. Assumed Agreements. Subject to consent of the other parties to
    such agreements, Parent agrees to cause to be assigned, and Buyer agrees to
    assume, all rights and obligations of Sellers, under the Agreements listed
    below (the "Assumed Agreements").

      2.13.1. DPM Agreement. The Copromotion Agreement between BMC and The
    DuPont Merck Pharmaceutical Company, Philadelphia, dated 20 December, 1996
    for the copromotion of the Product in the United States of America (the "DPM
    Agreement").

      2.13.2. PCI Agreement. The Packaging Agreement between BMC and Packaging
    Coordinators, Inc., Philadelphia, dated 29th June, 1995 for the assembling
    and packaging of the kits as defined in that agreement (the "PCI
    Agreement").

      2.13.3. Other Agreements. The agreements set forth on Schedule 2.13.3.

        2.14. Other Assets. Sellers shall sell, transfer and deliver to Buyer
    (i) trade secrets, customer and supplier lists of Sellers to the extent
    related to the Business and (ii) files of Sellers to the extent related to
    the Genentech Patent Suits.

        2.15. Tangible Assets. Sellers shall sell, transfer and deliver to Buyer
    certain tangible assets related solely to the Business as agreed by the
    parties in good faith prior to the Closing Date to be selected from the list
    set forth on Schedule 2.15, provided that Sellers shall not be obligated to
    transfer any such assets not owned by Sellers.

        2.16. Non-exclusive Licences. Subject to Section 3.5, Sellers shall
    grant and deliver to Buyer a non-exclusive, perpetual, paid-up, irrevocable,
    unlimited (except as provided in this Agreement) licence in the Territory
    under the Licenced Patents, the Licenced Patent Applications (and any and
    all divisions, continuations and continuations-in-part), the Know-How
    Licence and the Research and Development Materials Licence, with the right
    to sublicence, for use in the human pharmaceutical field.

                                      11
<PAGE>
 
        2.17. Limitation of Sale of Assets. Buyer expressly acknowledges that
    the Roche Group is retaining certain information identical to that contained
    in the Patents, Registrations, Know-How, Research and Development Materials
    Licence, Clinical Data, World-wide Safety Reports, Marketing and Promotional
    Documents and the other assets pursuant to Section 2 which is relevant for
    the research, development, manufacture, control, packaging or release,
    marketing or sale of products similar or identical to the Active Ingredient
    or the Product outside the Territory for their own and/or authorised third
    parties' use outside the Territory. Buyer further expressly acknowledges
    that except as provided in Section 2.16 the Roche Group is retaining (and
    are not transferring hereunder) any and all assets used solely in the
    research, development, manufacture, control, packaging or release, marketing
    or sale of other products or projects in the Territory or outside the
    Territory and may use, licence or dispose of such assets in their discretion
    and Buyer shall not have any right to any such assets.

3.  PURCHASE PRICE

         3.1. Purchase Price. Subject to the terms and conditions of this
    Agreement, in reliance on the representations, warranties, covenants and
    agreements of Parent contained herein and the representations and warranties
    of Sellers to be made to Buyer at Closing, and in consideration of the sale,
    conveyance, assignment, transfer and delivery of the Assets provided for in
    Section 2 hereof, Buyer will deliver at Closing in full payment for the
    aforesaid sale, conveyance, assignment, transfer and delivery, the Purchase
    Price of US $335 million; US $315 million of which shall be paid to Sellers,
    by bank wire transfer at such banking institutions as have been designated
    by Parent not less than five (5) days prior to Closing and US$ 20 million of
    which shall be deposited in an escrow account pursuant to arrangements to be
    negotiated in good faith by Parent and Buyer prior to the Closing Date. This
    amount (together with interest thereon) shall be returned to Buyer upon the
    meeting of manufacturing milestones consistent with the manufacturing
    arrangements set forth in Section 9.4. In the event such manufacturing
    milestones are not met by Buyer, such amount shall be paid to Sellers.

         3.2. Allocation of Purchase Price. The parties shall negotiate in good
    faith an allocation of the Purchase Price.

         3.3. Payment for Inventory. In addition to the Purchase Price according
    to Section 3.1 above, Buyer shall pay to Parent, acting on behalf of
    Sellers, in US dollars for the Inventory, based on the quantity document

                                      12
<PAGE>
 
    delivered pursuant to Section 2.12 by Parent at Closing; provided that, at
    the request of Parent, any such payment may be made directly to the relevant
    Seller. Buyer shall effect such payment by bank wire transfer so that Parent
    or relevant Seller shall receive it in its designated bank account within 10
    (ten) days from Closing.

         3.4. Refund of Purchase Price. (a) In the event Buyer, without any
    breach of this Agreement, as a result of (i) a binding determination
    (including a permanent, temporary or preliminary injunction for so long as
    such injunction is not stayed or vacated) in connection with the Genentech
    Patent Suits or (ii) a settlement of the Genentech Patent Suits; provided
    that such settlement is commercially reasonable for Buyer under the
    circumstances in absence of Parent's reimbursement obligations pursuant to
    this Section 3.4:

         (A)  becomes unable during the life of the relevant Genentech patents
         to engage in the manufacture or sale of the Product in the Territory,
         Parent, acting on behalf of Sellers, shall (1) in the event Buyer's
         inability to engage in the manufacture or sale of the Product in the
         Territory continues for a period of three months or less, reimburse
         Buyer for lost profits during such period in an amount not to exceed
         the Purchase Price (not including the escrow amount), (2) in the event
         Buyer's inability to engage in the manufacture or sale of the Product
         in the Territory continues for a period of greater than three months
         but less than or equal to six months, Parent shall refund 25% of the
         Purchase Price (not including the escrow amount) to Buyer, (3) in the
         event Buyer's inability to engage in the manufacture or sale of the
         Product in the Territory continues for a period of greater than six
         months but less than or equal to 12 months, Parent shall reimburse 75%
         of the Purchase Price (not including the escrow amount) to Buyer and
         (4) in the event Buyer's inability to engage in the manufacture or sale
         of the Product in the Territory continues for a period of greater than
         12 months, Parent shall reimburse 100% of the Purchase Price (not
         including the escrow amount) to Buyer, in each case net of payments to
         Buyer made pursuant to the clauses (1), (2) and (3), as the case may
         be; provided that in the event a binding determination occurs within
         six months prior to the expiration of the relevant Genentech patent or
         patents, Parent shall have no obligation to make a further refund of
         the Purchase Price to Buyer;

         (B)  becomes obligated to make payments to Genentech, Inc. or an
         affiliate thereof (1) for damages (including lost profits) or (2)

                                      13
<PAGE>
 
         for a reasonable royalty, in either case by reason of any award or
         agreement, Parent shall refund to Buyer any such payments actually made
         by Buyer;

         (C)  it being understood that the total payments to Buyer pursuant to
         paragraphs (A) and (B) above shall in no event exceed 125% of the
         Purchase Price (and in no event shall include any portion of the escrow
         amount that has already been returned to Buyer).

    (b)  Parent, acting on behalf of Sellers, shall pay 50% of all reasonable
    fees and expenses of attorneys (who are not employees of Buyer) and fees
    paid to agents, experts and courts incurred in connection with the defence
    (including counterclaims, nullity actions, opposition proceedings and
    appeals) of the Genentech Patent Suits, subject to audit of such fees and
    expenses by a nationally recognised independent auditor to be mutually
    agreed to by Parent and Buyer. The statements that are provided by such
    auditor to Parent setting forth the fees and expenses due shall not reveal
    any detailed confidential information regarding Buyer's conduct of, or
    strategy with respect to, the Genentech Patent Suits. Any expenses relating
    to in-house attorneys shall be paid by the party incurring such expenses.

    (c)  Buyer agrees to pursue vigorously the defence of the Genentech Patent
    Suits, including, subject to applicable law, to pursue in good faith any
    appeal of an adverse determination thereof.

         3.5. Royalty Payments.

       3.5.1. Buyer shall be required to make royalty payments and other
    arrangements under the circumstances described below for products other than
    the Product (and for the Product in the circumstance described in subsection
    (D)(x) of this Section 3.5.1), if following the Closing Date Buyer

          (i) commercialises any product (other than the Product or a future
          formulation of the Product) using any of the Licenced Patents, the
          Licenced Patent Applications (and any and all divisions, continuations
          and continuations-in-part), the Know-How Licence or the Research and
          Development Materials Licence; or

          (ii) sublicences or cross-licences any of the Licenced Patents, the
          Licenced Patent Applications (and any and all divisions,

                                      14
<PAGE>
 
THE REGISTRANT HAS REQUESTED CONFIDENTIAL TREATMENT FOR CERTAIN PORTIONS OF THIS
AGREEMENT. THOSE PORTIONS HAVE BEEN OMITTED FROM THIS COPY OF THE AGREEMENT AT 
THE PLACES INDICATED BY ASTERICKS (*); AND HAVE BEEN FILED SEPARATELY WITH THE 
SECURITIES AND EXCHANGE COMMISSION

          continuations and continuations-in-part), the Know-How Licence or the
          Research and Development Materials Licence, then the Roche Group shall
          receive value for such commercialisation, sublicencing or cross-
          licencing arrangements in accordance with the following principles:

              (A) if Buyer commercialises a product (other than the Product or a
              future formulation of the Product) that uses any of the Licenced
              Patents, the Licenced Patent Applications (and any and all
              divisions, continuations and continuations-in-part), the Know-How
              Licence or the Research and Development Materials Licence Buyer
              shall pay to the Roche Group an aggregate royalty of [*] of the
              net sales of such product;

              (B) if Buyer sublicences any of the Licenced Patents, the Licenced
              Patent Applications (and any and all divisions, continuations and
              continuations-in-part), the Know-How Licence or the Research and
              Development Materials Licence to a third party in return for a
              royalty payment, Buyer shall pay to the Roche Group [*] of such
              royalty payment;

              (C) if Buyer cross-licences any of the Licenced Patents, the
              Licenced Patent Applications (and any and all divisions,
              continuations and continuations-in-part), the Know-How Licence or
              the Research and Development Materials Licence to a third party
              and receives any right to such third party's products or products
              in development, and Buyer commercialises such products, then Buyer
              shall pay to the Roche Group an aggregate royalty of [*] of the
              net sales of such products;

              (D) if Buyer cross-licences to a third party any of the Licenced
              Patents, the Licenced Patent Applications (and any and all
              divisions, continuations and continuations-in- part), the Know-How
              Licence or the Research and Development Materials Licence and
              receives the right to use any of such third party's manufacturing
              technology, then if such manufacturing technology is

                   (x) specifically applicable to the Product (or a future
                   formulation of the Product) and Buyer obtains a

                                      15

                       Confidential Treatment Requested
<PAGE>

THE REGISTRANT HAS REQUESTED CONFIDENTIAL TREATMENT FOR CERTAIN PORTIONS OF THIS
AGREEMENT. THOSE PORTIONS HAVE BEEN OMITTED FROM THIS COPY OF THE AGREEMENT AT 
THE PLACES INDICATED BY ASTERICKS (*); AND HAVE BEEN FILED SEPARATELY WITH THE 
SECURITIES AND EXCHANGE COMMISSION
 
                   worldwide sublicence therefor, Buyer shall grant to the Roche
                   Group a non-exclusive, perpetual, paid-up, irrevocable,
                   royalty-free licence for use in the manufacture of the
                   Product (or a future formulation of the Product) outside the
                   Territory;

                   (y) applicable to products other than the Product (or a
                   future formulation of the Product) and Buyer obtains a
                   worldwide licence therefor, the Roche Group shall have the
                   option to receive (1) a non-exclusive, perpetual, paid-up,
                   irrevocable, royalty-free sublicence to such manufacturing
                   technology for use in the manufacture of any such products or
                   (2) [*] of the gross margin benefit achieved by Buyer as a
                   result of Buyer's application of such manufacturing
                   technology to any such products; or

                   (z) applicable to products other than the Product (or a
                   future formulation of the Product) and Buyer obtains a
                   licence therefor limited to the Territory, the Roche Group
                   shall receive [*] of the gross margin benefit achieved by
                   Buyer as a result of Buyer's application of such
                   manufacturing technology to any such products;

              (E) if Buyer enters into any sublicence or cross-licence
              arrangement in connection with any of the Licenced Patents, the
              Licenced Patent Applications (and any and all divisions,
              continuations and continuations-in-part), the Know-How Licence or
              the Research and Development Materials Licence not specifically
              described in clauses (A) through (D), Parent and Buyer agree to
              negotiate in good faith an arrangement based upon the principles
              set forth above.

       3.5.2. If the Roche Group is entitled to receive payments pursuant to
    Section 3.5.1, Buyer shall promptly inform the Roche Group of its
    entitlement to such payments and an independent auditor may, upon the
    request of the Roche Group, be appointed to verify the amount of any such
    payment properly due to the Roche Group and the Roche Group and Buyer shall
    implement procedures to ensure that no confidential information is shared
    between the parties in connection with the calculation or verification of
    such payments.

                                      16

                       Confidential Treatment Requested
<PAGE>
 
4.   REPRESENTATIONS AND WARRANTIES OF PARENT

         Parent hereby represents and warrants as follows:

         4.1. Organisation. Parent is a corporation duly organised, validly
     existing and in good standing under the laws of Bermuda, with full
     corporate power and authority to consummate the transactions contemplated
     hereby.

         4.2. Authority. The execution, delivery and performance of this
     Agreement by Parent have been duly and validly authorised by all necessary
     corporate proceedings, and this Agreement has been duly authorised,
     executed, and delivered by Parent and, assuming the enforceability against
     Buyer, will constitute the legal, valid and binding obligation of Parent,
     enforceable in accordance with its terms.

         4.3. No Violation or Conflict. The execution, delivery and performance
     of this Agreement by Parent (a) do not and will not conflict with, violate
     or constitute or result in a default under any law, judgement, order,
     decree, the memorandum of association of Parent or any contract or
     agreement to which Parent or Sellers are a party or by which Parent or
     Sellers are bound or (b) will not result in the creation or imposition of
     any lien, charge, mortgage, claim, pledge, security interest, restriction
     or encumbrance of any kind on, or liability with respect to, the Assets
     except as otherwise provided herein or otherwise disclosed on the
     Disclosure Schedule.

         4.4. No Government Restrictions. Except as required pursuant to the HSR
     Act or as otherwise contemplated by this Agreement, no consent, approval,
     order or authorisation of, or registration, declaration or filing with, any
     governmental agency is required to be obtained or made by or with respect
     to Parent in connection with the execution, delivery and performance of
     this Agreement by Parent.

         4.5. Title to Assets. Except as set forth in Section 4.5 of the
     Disclosure Schedule, Sellers have good and marketable title to all the
     Assets and will, subject to other provisions of this Agreement and the
     Disclosure Schedule, convey good and marketable title at Closing, free and
     clear of any and all liens, encumbrances, charges, claims, restrictions,
     pledges, security interests, or impositions of any kind (including those of
     secured parties). Except as set forth in Section 4.5 of the Disclosure
     Schedule, Sellers beneficially own all of the rights, title or other
     interests


                                      17
<PAGE>
 
     to be transferred to Buyer with respect to all the Assets and none of the
     Assets is leased, rented, licenced, or otherwise not owned by Sellers.
     Parent also represents that the Roche Group will not retain any copies of
     customer lists exclusively used in the Business.

         4.6. Patents. The Patents and the patents underlying the Licenced
     Patents and the patent applications underlying the Licenced Patent
     Applications have been applied for by and/or granted to BM. Except as
     disclosed on Section 4.6 of the Disclosure Schedule, to the best of
     Parent's knowledge (i) the manufacture, use or sale of the Product does not
     infringe on any other patent in any material respect which would prohibit
     the manufacture of the Product in the Territory or in Germany or the use or
     sale of the Product in the Territory; (ii) there are no claims, demands or
     proceedings instituted, pending or seriously threatened by any third party
     pertaining to or challenging BM's rights to any Patents or patents
     underlying the Licenced Patents or any patent application underlying the
     Licenced Patent Applications; (iii) Parent and Sellers are not aware of any
     facts which would render any of the Patents or patents underlying the
     Licenced Patents or any patent application underlying the Licenced Patent
     Applications, invalid or unenforceable. It is understood that a disclosure
     made in any section of the Disclosure Schedule is made solely for the
     purpose of this Agreement and does not imply any acknowledgment of Parent
     or Sellers that any third party rights exist or that the Product infringes
     any third party right.

         4.7. Trademarks. Sellers own the Trademarks set forth in Schedule 2.5
     which are formally registered or applied. All Trademark applications set
     forth in Schedule 2.5 have been duly filed and maintained. Except as
     disclosed on Section 4.7 of the Disclosure Schedule, to the best of
     Parent's knowledge (i) the use of the Trademarks for the Product in the
     Territory does not infringe on any other trademark in any material respect
     which would prohibit the use of the Trademarks for the Product in the
     Territory, and (ii) there are no claims, demands or proceedings instituted,
     pending or seriously threatened by any third party pertaining to or
     challenging Sellers' rights to any Trademark in the Territory.

         4.8. Registrations. All Registrations held by Sellers in the Territory
     are listed on Schedule 2.6. The Registrations (a) are in the name of
     Sellers, (b) constitute all licences, permits, approvals, qualifications,
     and governmental specifications, authorisations or requirements which
     Sellers have in connection with the marketing and sale of the Product in
     the Territory, and (c) to the best of Parent's knowledge, constitute all
     such licences, permits, approvals, qualifications, and governmental

                                      18
<PAGE>
 
     specifications, authorisations, and requirements necessary for the
     marketing and sale of the Product in the Territory as currently conducted
     by Sellers.

         4.9. Know-How and Know-How Licence. The Know-How and Know-How Licence
     together with the Buyer's own resources will be sufficient to permit Buyer
     (or a third party designated by Buyer) to manufacture, control, package or
     release (as applicable) the Active Ingredient or the Product to the same
     standards as Sellers currently enjoy or will enjoy as of the termination of
     the Supply Agreement.

        4.10. Inventory. As of the Closing, the Inventory shall meet the
     specifications therefor as set forth in the manufacturing documentation and
     Registrations for such Product with the competent authorities in the
     country concerned of the Territory. The Inventory will be in good
     condition, properly stored, having a minimum of 12 months of expiration
     dating from the Closing Date and in compliance with applicable laws, usable
     and saleable in the ordinary course of business.

        4.11. Taxes. As of the date hereof, there are no liens for taxes upon
     the Assets except for liens for current taxes not yet due and payable.

        4.12. Absence of Certain Changes. As of the date hereof and as of the
     Closing Date and except as set forth on Section 4.12 of the Disclosure
     Schedule, there has not been any material adverse change in the Assets or
     the Business and Parent and Sellers are not aware of any facts or
     circumstances that would have a Material Adverse Effect after Closing.

        4.13. Violations of Law. Except as set forth in Section 4.13 of the
     Disclosure Schedule or otherwise in this Agreement and the Disclosure
     Schedule, to the best of Parent's knowledge, the utilisation of the Assets
     and the conduct of the Business by Sellers (i) does not violate or conflict
     with any law, governmental specification, authorisation, or requirement, or
     any decree, judgement, order, or similar restriction in any material
     respect, or (ii) has not been the subject of an investigation or inquiry by
     any governmental agency or authority regarding violations or alleged
     violations, or found by any such agency or authority to be in violation, of
     any law, other than investigations, inquiries or findings that have not
     had, or are reasonably likely not to have, a Material Adverse Effect.

        4.14. Financial Information.

                                      19
<PAGE>
 
        4.14.1. The BM Monthly Sales Statements have been and will be accurate
     and complete in all material respects, reflect only actual bona fide
     transactions, are consistent with the accounting records of the BM Group
     legal entities, contain or will be made to contain information to enable
     Buyer to determine the nature and amounts of all deductions from gross
     sales necessary to calculate BM Net Sales, and were and will be prepared in
     a manner consistent with principles applied under U.S. generally accepted
     accounting principles (GAAP) consistently applied.

        4.14.2. None of Sellers and their Affiliates have any material
     liabilities, contingent, absolute, accrued or otherwise, relating to the
     Assets.

        4.15.   Litigation. Except as set forth on Section 4.15 of the
     Disclosure Schedule or otherwise in this Agreement and the Disclosure
     Schedule, to the best of Parent's knowledge, the Assets are not the subject
     of (i) any outstanding judgement, order, writ, injunction or decree of any
     arbitrator or administrative or governmental authority or agency, limiting,
     restricting or affecting the Assets in a way that would have a Material
     Adverse Effect, (ii) any pending or, to the best of Parent's knowledge,
     seriously threatened claim, suit, proceeding, charge, inquiry,
     investigation or action of any kind, and (iii) any court suits filed with
     respect to the Assets since 1 January 1996. Subject to other provisions of
     this Agreement, to the best of Parent's knowledge, there are no claims,
     actions, suits, proceedings or investigations pending or threatened by or
     against Sellers or Parent with respect to the transactions contemplated
     hereby, at law or in equity or before or by any federal, state, municipal
     or other governmental department, commission, board, agency,
     instrumentality or authority that would have a Material Adverse Effect.

        4.16.   Sufficiency of Assets. The Patents, Licenced Patents, Licenced
     Patent Applications, Registrations, Know-How and Know-How Licence being
     transferred to Buyer are all of the patents, licenced patents, licenced
     patent applications, registrations, know-how and know-how licences
     necessary to enable Buyer to produce the Product in the Territory.

        4.17.   Conduct of Business. Subject to applicable laws and regulations
     and the Stock Purchase Agreement, Sellers have conducted the Business in
     accordance with customary business practices and the 1997 marketing plan or
     the 1998 marketing plan, as applicable, and have taken all reasonable steps
     to maintain the Business, including reasonable incentives to maintain the
     marketing and sales personnel relating to sales of the Product in the
     United States.

                                      20
<PAGE>
 
        4.18. Retavase Business. Nothing in this Section 4 shall be construed as
     a representation or warranty by Parent with respect to the Retavase
     Business as conducted by Buyer following the Closing Date.

5.   REPRESENTATIONS AND WARRANTIES OF BUYER

         Buyer represents and warrants as follows:

         5.1. Organisation. Buyer is a corporation duly organised, validly
     existing and in good standing under the laws of the Commonwealth of
     Pennsylvania, has all corporate powers and material governmental licences,
     authorisations, permits, consents and approvals required to carry on its
     business as currently conducted and has full corporate power and authority
     to consummate the transactions contemplated hereby.

         5.2. Authority. The execution, delivery and performance of this
     Agreement by Buyer have been duly and validly authorised by all necessary
     corporate proceedings, and this Agreement has been duly authorised,
     executed, and delivered by Buyer and, assuming the enforceability against
     Parent, constitutes the legal, valid and binding obligation of Buyer,
     enforceable in accordance with its terms.

         5.3. No Violation or Conflict. The execution, delivery and the
     performance of this Agreement by Buyer do not and will not conflict with,
     violate or constitute or result in a default under any law, judgement,
     order, decree, the articles of incorporation or bylaws of Buyer, or any
     contract or agreement to which Buyer is a party or by which Buyer is bound.

         5.4. No Government Restrictions. Except as required pursuant to the HSR
     Act or as set forth in Schedule 5.4 no consent, approval, order or
     authorisation of, or registration, declaration or filing with, any
     governmental agency is required to be obtained or made by or with respect
     to Buyer in connection with the execution, delivery and performance of this
     Agreement by Buyer.

         5.5. Litigation. There are no claims, actions, suits, proceedings or
     investigations pending or, to the best of Buyer's knowledge, threatened by
     or against Buyer with respect to the transactions contemplated hereby, at
     law or in equity or before or by any federal, state, municipal or other
     governmental department, commission, board, agency, instrumentality or
     authority.

                                      21
<PAGE>
 
         5.6. Financing. Buyer has received, and furnished a copy to Parent of,
     a commitment letter signed by Buyer and Morgan Stanley & Co. Incorporated
     ("Morgan Stanley") in a form satisfactory to Parent (the "Commitment
     Letter") to provide the financing for the Purchase Price and the Commitment
     Letter is in full force and effect. Buyer shall have at Closing sufficient
     funds to pay the Purchase Price.

         5.7. Assets. Buyer is, and/or has engaged expert advisors, experienced
     in the evaluation and purchase of property and assets such as the Assets as
     contemplated hereunder. Buyer has undertaken such investigation and has
     been provided with and has evaluated such documents and information as it
     has deemed necessary to permit it to make an informed and intelligent
     decision with respect to the execution, delivery and performance of this
     Agreement. Buyer has satisfied itself that the Assets will, if transferred
     to Buyer as provided in Section 2, permit Buyer, together with the
     activities to be performed by Parent and its Affiliates pursuant to the
     Supply Agreement, the Transition Services Agreement and the resources to be
     provided by Buyer, as contemplated by Buyer's plan for the Retavase
     Business presented to the FTC, to conduct the Retavase Business immediately
     after the Closing Date.

6.   PARENT'S COVENANTS

         Parent covenants and agrees as follows:

         6.1. Maintenance of Assets/Conduct of Business. Parent agrees that from
     the date hereof until the Closing Date, except as specifically disclosed in
     Section 6.1 of the Disclosure Schedule or unless otherwise consented to by
     Buyer in writing, Parent shall, subject to applicable laws and regulations,
     use its efforts to cause Sellers to preserve the Assets and to conduct the
     Business in the ordinary course as set forth in the Stock Purchase
     Agreement. From the closing of the Stock Purchase Agreement, Parent
     undertakes as follows:

       6.1.1. except as set forth in this Agreement or disclosed on the
     Disclosure Schedule to cause Sellers and their Affiliates to maintain the
     Assets in good status and condition and not sell or dispose of any of the
     Assets except in the ordinary course of business;

       6.1.2. to cause Sellers and their Affiliates to not make or institute any
     unusual or novel methods of purchase, manufacture, sale, wholesale
     inventory build-up, management, operation, or other business practice in
     the conduct of the Business inconsistent with past practices; wholesale

                                      22
<PAGE>
 
     inventory build-up at the Closing Date shall not materially exceed two
     month's supply, except as otherwise agreed by Parent and Buyer;

       6.1.3. to cause Sellers not to enter into any material contract or
     commitment, engage in any transaction, extend credit or incur any
     obligation with respect to the Business, in each case not in the usual and
     ordinary course of business and consistent with normal business practices;
     and

       6.1.4. to inform Buyer promptly of any change in the Assets or the
     Business that would have a Material Adverse Effect.

         6.2. Compliance with Laws. Except as otherwise disclosed on the
     Disclosure Schedule, Parent shall comply or begin to remedy any non-
     compliance or cause Sellers to comply or begin to remedy, any non-
     compliance upon notification thereof in all material respects with all laws
     and orders of any court or federal, state, local or other governmental
     entity applicable to the Assets or the Business except where such that any
     non-compliance will not have a Material Adverse Effect at or after Closing.

         6.3. Access.

       6.3.1. From and after the date hereof and up to the Closing Date (except
     as otherwise provided herein) subject to applicable laws and regulations,
     Parent shall use reasonable efforts to cause Sellers to grant Buyer and its
     authorised agents, officers, and representatives access to the Assets
     during normal business hours upon reasonable prior notice and at a time and
     manner mutually agreed upon between Buyer and Parent in order to conduct
     such examination and investigation of the Assets as is reasonably
     necessary, provided that such examinations shall not unreasonably interfere
     with the operations and activities of Sellers.

       6.3.2. Parent will not, and will cause Sellers not to, disclose any
     confidential information relating to the Business to other entities of the
     Roche Group from and after the closing of the Stock Purchase Agreement up
     to the Closing Date.

         6.4. Patent Maintenance and Defence. As to any patents and patent
     applications licenced to Buyer pursuant to this Agreement, Parent shall
     assume, or cause Sellers to assume the following obligations for the
     Territory: (a) to pay all prosecution cost for any pending patent
     application; (b) to pay all maintenance fees; (c) to keep Buyer advised of
     the status of all patent documents embraced by items (a) and (b) above;

                                      23
<PAGE>
 
     (d) to advise Buyer of any actual or, to the best of Parent's knowledge,
     potential acts of infringement by any party; (e) to pursue and pay for all
     available extensions; and (f) not to abandon any patent or patent
     application underlying the Licenced Patents or Licenced Patent Applications
     without giving Buyer written notice of at least 6 (six) months in advance
     of any action toward abandonment in order for Buyer to take responsibility
     for maintenance of such patent. To the extent Buyer has a licence under
     this Agreement for a patent of Sellers, Buyer shall be solely responsible
     for the defence of any patent suit relating to the Product in the
     Territory. Buyer shall not abandon or interfere with any other aspect of
     such patents.

         6.5. Sale of Retavase by the Roche Group. During the term of the Supply
     Agreement the Roche Group will not sell any assets used by the Roche Group
     to supply Buyer with the Active Ingredient pursuant to the Supply
     Agreement. If during the one year period following commencement by Buyer or
     a third party designated by Buyer of the manufacture of the Product for
     sale in the Territory, the Roche Group desires to sell all of the assets
     relating solely to the research, development, manufacture, control,
     packaging or release, marketing or sale of the Active Ingredient and the
     Product outside the Territory to a third party, the Roche Group shall give
     written notice to Buyer that the Roche Group desires to effect such a sale.
     Buyer shall have a 30-day period in which to make an offer (the "Offer") to
     purchase all of the assets relating solely to the research, development,
     manufacture, control, packaging or release, marketing or sale of the Active
     Ingredient and the Product outside the Territory by giving a written notice
     to Parent or its Affiliate containing the proposed price and any other
     material terms prior to the expiration of such 30-day period. The Roche
     Group shall have the right in its sole discretion to accept or reject the
     Offer. In the event Parent or its Affiliate rejects the Offer, the Roche
     Group shall have the right to effect a sale of such assets to a third party
     on substantially the same or more favourable terms from the perspective of
     the Roche Group as set forth in the Offer.

         6.6. Sales Force. Parent agrees to continue the currently implemented
     stay-bonus program for the sales and marketing employees of the Business
     through the earlier of (i) April 20, 1998 or (ii) the Closing Date.

         6.7. Further Assurances. Parent shall use all reasonable efforts to
     implement the provisions of this Agreement, and for such purpose Parent, at
     the request of Buyer, at or after Closing, will, without further
     consideration, execute and deliver, or cause to be executed and delivered,

                                      24
<PAGE>
 
     to Buyer such deeds, assignments, bills of sale, consents and other
     instruments in addition to those required by this Agreement, in form and
     substance satisfactory to Buyer, as Buyer may reasonably deem necessary or
     desirable to implement any provisions of this Agreement.

         6.8. Nonassertion. Notwithstanding the other provisions of this
     Agreement, the Roche Group shall not assert or cause to be asserted against
     Buyer, the contract manufacturer of Buyer or any customer of Buyer any
     cause of action based upon infringement of any patents or patent
     applications existing as of the Closing Date or patents issuing on such
     patent applications of the Roche Group based on Buyer's conduct of the
     Business following the Closing Date. For the avoidance of doubt, nothing
     shall prevent the Roche Group or Buyer and its Affiliates from using any
     technology that is in or comes into the public domain.

         6.9. Genentech Disclosure. During the pendency of the Genetech Patent
     Suits, Parent agrees that the Roche Group (including officers, directors
     and employees of the Roche Group) will not disclose to any officer,
     director or employee of Genentech, Inc., unless compelled to disclose by
     judicial or administrative process or by other requirements of law, any
     confidential information obtained by the Roche Group in connection with the
     Corange Transaction (i) relating solely to the Business, or (ii) not
     relating solely to the Business which would disclose to Genetech, Inc. the
     application to thrombolytic drugs having essentially the same structure and
     functionality as Retavase of any of the matters or know-how licenced to
     Buyer pursuant to Section 2.16; provided that such obligation shall not
     prevent the Roche Group from disclosing, to the extent necessary, such
     confidential information to any person who is an officer, director or
     employee of F. Hoffmann-La Roche Ltd or its Affiliates who is also a
     director of Genentech, Inc. Information shall not be deemed to be
     confidential to the extent that such information (i) was in the public
     domain prior to the date of this Agreement or thereafter enters the public
     domain through no fault of the Roche Group or its representatives, (ii) was
     available to the Roche Group on a non-confidential basis, (iii) is later
     lawfully acquired by the Roche Group from sources other than the Roche
     Group or its representatives who are not subject to any legally binding
     obligation to keep such information confidential, or (iv) independently
     developed by the Roche Group.

        6.10. Control of Genentech, Inc. In the event that (i) the Amended and
     Restated Governance Agreement between Genentech, Inc. and Roche Holdings,
     Inc. dated October 25, 1995 allows the Roche Group to control Genentech,
     Inc. or (ii) the Roche Group obtains 100% of the stock of

                                      25
<PAGE>
 
         Genentech, Inc., the Roche Group shall cause to be dismissed, with
         prejudice, the Genentech Patent Suits and shall cause Genentech, Inc.
         to refrain from instituting any new litigation against Buyer as
         provided for in the Agreement Containing Consent Order.

                  6.11. Keep Well Agreement. On or prior to the Closing Date,
         Parent shall enter into a Keep Well Agreement (the "Keep Well") with
         Roche Holding Ltd in substantially the form set forth in Exhibit D.
         Parent further agrees that it shall not agree to any modification,
         amendment or termination of the Keep Well if such modification,
         amendment or termination shall have any adverse effect upon the ability
         of Parent to meet its obligations under Section 3.4 and Section 13.7 of
         this Agreement without the written consent of Buyer.

7.       BUYER'S COVENANTS

                  Buyer covenants and agrees as follows:

                  7.1. Approvals and Registrations for Transfer of Distribution
         of Products. Following Closing, Buyer shall use all reasonable efforts
         and, except as otherwise set forth herein, at its own expense obtain as
         expeditiously as possible such governmental approvals and registrations
         from the competent regulatory authorities in the Territory, as may be
         necessary with respect to the conduct of the Retavase Business by Buyer
         or its designee (other than Parent or an Affiliate of Parent).

                  7.2. Labelling. Following Closing, Buyer shall at its own
         expense and as expeditiously as possible use all reasonable efforts to
         create, and to obtain such approvals of competent government
         authorities in the Territory necessary for, Buyer's labelling for the
         Product. Buyer may use the BM Labelling on the Inventory until such
         Inventory is exhausted, subject to applicable laws and regulations in
         the Territory. In addition, Buyer may, subject to applicable laws of
         the relevant countries of the Territory, use the BM Labelling on each
         Product manufactured by Parent or its Affiliates (including without
         limitation the BM Group companies) for Buyer until the competent
         authority approves Buyer's Labelling for use on the Product and Buyer,
         using all efforts, has obtained sufficient supplies of materials with
         Buyer's Labelling for use on such Product. Buyer may, however, use the
         BM Labelling only in connection with clearly identifying Buyer as the
         responsible person for commercialising the Product in a way approved in
         advance by Parent, such approval not to be unreasonably withheld. All
         expenses incurred by Buyer




                                      26
<PAGE>
 
         in connection with Buyer's labelling and package design of the Product
         shall be solely for the account of Buyer.

                  7.3. References to Parent. Other than as set forth in Section
         7.2 above, any reference to Parent or its Affiliates (including without
         limitation the BM Group companies) or any use of the trademarks,
         tradenames, or logos of Parent or its Affiliates (including without
         limitation the BM Group companies) by Buyer in connection with the
         Product after Closing must be approved by Parent in writing prior to
         such use unless otherwise required by law or regulation; provided that
         Buyer may refer to Sellers to the extent necessary to identify Sellers
         as having previously sold the Product in the Territory. It is
         understood that the Trademarks do not fall under this provision.

                  7.4. Further Assurances. Buyer shall use all reasonable
         efforts to implement the provisions of this Agreement, and for such
         purpose Buyer, at the request of Parent, at or after Closing, will,
         without further consideration, execute and deliver, or cause to be
         executed and delivered, to Parent such consents and other instruments
         in addition to those required by this Agreement, in form and substance
         satisfactory to Parent, as Parent may reasonably deem necessary or
         desirable to implement any provision of this Agreement.

                  7.5. Financing. Buyer agrees to use its best efforts to
         complete the financing referred to in Section 5.6 including, without
         limitation, to (i) perform all of Buyer's obligations under the
         Commitment Letter; (ii) take all actions necessary to cause the
         conditions under the Commitment Letter to be satisfied; (iii) not take
         any action which would be reasonably expected to cause such conditions
         not to be satisfied; (iv) not amend or waive any provision of the
         Commitment Letter without the prior written consent of Parent and (v)
         enforce its rights against Morgan Stanley & Co. Incorporated under the
         Commitment Letter.

                  7.6. Notification. If at any time Buyer becomes aware of any
         facts or circumstances which would be reasonably likely to result in a
         failure of any condition to Morgan Stanley's obligations under the
         Commitment Letter, Buyer shall promptly notify Parent in writing
         describing the same in reasonable detail.





                                      27
<PAGE>
 
8.       COVENANTS BY BUYER AND PARENT

                  Buyer and Parent covenant and agree as follows:

                  8.1. Assignment of Patents and Trademarks. By or before
         Closing, Buyer and Parent shall prepare in good faith an assignment
         pursuant to which Sellers agree the Patents and Trademarks shall be
         assigned to Buyer. Following Closing, Buyer shall prepare and Sellers
         shall execute such documents as Buyer may reasonably request in order
         to assign and record the assignment of the Patents and Trademarks. The
         responsibility and expense of preparing and filing such documents and
         any actions required ancillary thereto, shall be borne solely by Buyer.
         Notwithstanding anything contained elsewhere herein, Buyer shall hold
         Parent and its Affiliates (including without limitation the BM Group
         companies) harmless from and against any loss or damage, including but
         not limited to fees, penalties, fines or third party claims, due to
         Buyer's failure to record any assignment of any such Patents or
         Trademarks pursuant to this Section 8.1, except if such loss or damage
         is solely due to the conduct of Parent (including without limitation
         the BM Group companies).

                  Neither Parent nor any of its Affiliates (including without
         limitation the BM Group companies) shall be obliged to maintain any
         Trademark after the Closing. Parent will pay or cause to be paid any
         fees for renewals of any of the Trademarks as were initiated prior to
         the Closing. All other renewal and maintenance fees as well as the cost
         and expenses for defending the Trademarks against infringements by
         third parties occurring after the Closing Date shall be paid by Buyer.
         Parent will arrange for the files relating to the Trademarks to be
         handed over to Buyer without delay after the Closing. Until the
         termination of the Transition Services Agreement, Parent will promptly
         notify Buyer of any infringement or threatened infringement of any of
         the Trademarks coming to its attention and will, if the registration of
         any of the Trademarks is still in the name of Sellers, at the expense
         of Buyer take such action against the infringer as Buyer may reasonably
         request to restrain such infringement, or alternatively authorise Buyer
         or its nominee to take such action in its own name. In the latter
         event, Parent or its Affiliates will at Buyer's expense provide
         reasonable assistance to Buyer.

                  8.2. Assignment of Registrations. Parent and Buyer shall
         cooperate to ensure that the Registrations shall be assigned to Buyer,
         except where such assignment may be prohibited by law. At or following
         Closing, Buyer shall prepare and Sellers shall execute such documents
         as




                                      28
<PAGE>
 
         Buyer may reasonably request in order to record the assignment of the
         Registrations. The responsibility and expense of preparing and filing
         such documents and any actions required ancillary thereto shall be
         borne solely by Buyer. In addition, Buyer shall pay any user fees
         associated with any Product that accrues after Closing but prior to
         transfer of such Registration. Notwithstanding anything contained
         elsewhere herein, Buyer shall hold Parent and its Affiliates (including
         without limitation the BM Group companies) harmless from and against
         any loss or damage, including but not limited to fees, penalties, fines
         or third party claims, due primarily to Buyer's failure to record any
         assignment of any such Registrations pursuant to this Section, except
         if such loss or damage is due primarily to the conduct of Parent and
         its Affiliates (including without limitation the BM Group companies).

                  8.3. Clinical Studies Transfer. Parent and Sellers shall
         complete ongoing clinical studies which are scheduled to be completed
         within two (2) months from the Closing Date and following completion
         shall provide electronic copies of the relevant Clinical Data and all
         reports relating to such clinical studies to Buyer. Ongoing clinical
         studies scheduled to be completed after two (2) months from the Closing
         Date shall be transferred to Buyer. Parent and Buyer shall cooperate in
         the transfer of such studies and all other materials related thereto.

                  8.4. Access to Information. Buyer and Parent will, upon
         reasonable prior notice, make available to the other, to the extent
         reasonably required for the purpose of assisting Parent or Buyer in
         obtaining governmental approvals and preparation of tax returns or
         other filings required by law or regulation relating to the Assets, and
         prosecuting or defending or preparing for the prosecution or defence of
         any action, suit, claim, complaint, proceeding or investigation at any
         time brought by or pending against Parent or any of its Affiliates
         (including without limitation the BM Group companies) or Buyer relating
         to the Assets or the Supply Agreement, other than in the case of
         litigation between the parties hereto, such information or records (or
         copies thereof) in their possession after Closing.

                  8.5. Press Releases. Except as required by applicable law,
         neither Parent nor Buyer, nor any Affiliate thereof, will issue or
         cause publication of any press release or other announcement or public
         communication with respect to this Agreement or the transactions
         contemplated hereby without the prior written consent of the other
         party, which consent will not be unreasonably withheld or delayed. To
         the extent that any announcement is




                                      29
<PAGE>
 
         required by applicable law, Parent and Buyer shall consult with each
         other in good faith prior to such announcement.

                  8.6. Customer Information. Buyer jointly with Parent or their
         relevant Affiliates shall be entitled and obliged to announce to the
         clients in the Territory, the transfer of the Business to Buyer or its
         relevant Affiliate.

                  8.7. Hospital and Other Purchasing Contracts. Buyer and Parent
         shall take such actions as are reasonably necessary to cause the
         assignment to Buyer of hospital and other health services provider
         purchasing contracts for the purchase of the Product. Those contracts,
         if any, that relate to the purchase of the Product as well as other
         products shall be terminated by Sellers with respect to the Product as
         soon as practicable after closing so as to allow Buyer to enter into
         new contracts with respect to the Product.

                  8.8.   Reconciliation with the Agreement Containing Consent
         Order; Canadian Filings.

                  8.8.1. If required by the FTC, Parent and Buyer will cooperate
         with one another and will negotiate in good faith to amend any
         provision of this Agreement to the extent necessary to make the
         provisions hereof consistent with the Agreement Containing Consent
         Order; provided that no such amendment shall be required to be made
         unless it is acceptable to Buyer and Parent.

                  8.8.2. The parties hereto shall promptly make or cause to be
         made all filings required or deemed advisable under the Competition Act
         (Canada). If required by law, the transaction contemplated by this
         Agreement is contingent upon (i) the issuance under section 102 of the
         Competition Act (Canada) of an Advance Ruling Certificate or (ii) the
         expiry of the waiting period under section 123 of the Competition Act
         (Canada) and receipt of advice in writing by the Director that he has
         determined not to make an application for an order under section 92 or
         100 of the Competition Act (Canada) or to commence an inquiry under
         section 10 of the Competition Act (Canada). The transaction
         contemplated by this Agreement is further contingent upon completion of
         any filings and obtaining of any approvals under the Investment Canada
         Act if required.

                  8.9.   Genentech Patent Suits.





                                      30
<PAGE>
 
                  8.9.1. Buyer covenants that, immediately upon Closing, Buyer
         will undertake, in good faith, control of the full and complete defence
         of the Genentech Patent Suits. Parent represents and Buyer acknowledges
         that the Assets to be transferred to Buyer pursuant to this Agreement
         include all assets that are currently utilised by BM in its defence of
         the Genentech Patent Suits, to the extent such assets are owned by the
         BM Group at Closing. Buyer undertakes in good faith to not abandon or
         make any concessions in the defence of the Genentech Patent Suits in
         Germany which affects the ability of Parent or any of its Affiliates
         (including without limitation the BM Group companies) to manufacture or
         sell the Active Ingredient or the Product or any product made therewith
         outside the Territory or any other product or research or development
         project in or outside the Territory. Buyer shall retransfer control of
         defence of the Genentech Patent Suits in Germany immediately upon
         commencement by Buyer of the manufacture of the Product outside Germany
         in the event such suits are still pending at that time.

                  8.9.2. Parent undertakes that during the pendency of the
         Genentech Patent Suits (or any appeals relating to such suits), Parent
         will take all steps to make available to Buyer (i) such employees of
         the Roche Group that are knowledgeable with respect to the matters at
         issue in the Genentech Patent Suits (including without limitation the
         BM Group companies) and (ii) such relevant files of the BM Group (which
         exist as of the Closing Date and which Parent undertakes to preserve)
         that Buyer may reasonably require in connection with the defence of the
         Genentech Patent Suits for such period of time as may be reasonably
         required by Buyer. In particular, Parent agrees that with respect to
         Stefan Fischer, Ulrich Konert, Anne Stern, Siegfried Schreiner, and
         Claus-Jorg Rutsch, Parent will ensure that, for such period of time as
         such individuals are employed by the Roche Group, the availability of
         such individuals to Buyer in connection with the Genentech Patent Suits
         shall not be interfered with by reason of their employment with the
         Roche Group. In addition, to the extent that such individuals are not
         employed by the Roche Group, Buyer or its Affiliates, Parent shall pay
         all reasonable direct out-of-pocket expenses (and reasonable fees, if
         permissible) of any such individual who participates in the defence of
         the Genentech Patent Suits incurred in connection therewith. Parent
         further agrees that it will take no adverse action against any employee
         of the Roche Group based on such employee's provision of assistance or
         information to Buyer pursuant to this Section 8.9.2. Parent also agrees
         that, to the extent relevant and necessary, it will not enforce any
         confidentiality agreement against an employee of the Roche Group that
         would otherwise prevent or hinder such





                                      31
<PAGE>
 
         employee from cooperating with or providing information to Buyer
         pursuant to this Section 8.9.2.

                  8.10. Transition Services. On or prior to the Closing Date,
         Buyer and Parent or their Affiliates shall enter into the Transition
         Services Agreement substantially in the form attached as Exhibit A
         hereto.

                  8.11. Returns. For a period of two years following the Closing
         Date, Sellers shall be responsible for all returns of the Product
         within the Territory with respect to lot numbers shipped prior to the
         Closing Date, provided that following the Closing Date, Buyer shall not
         engage in any action (other than pricing of the Product) to induce any
         purchaser of the Product to return Product sold prior to the Closing
         Date; provided, however, that to the extent returns of Product result
         from changes in pricing by Buyer, Buyer shall be responsible for such
         returns. For Product shipped after the Closing Date, Buyer shall be
         responsible for all returns of the Product within the Territory.

                  8.12. Chargebacks and Rebates. Sellers shall be responsible
         for all chargebacks and rebates which are reported within 60 days
         following the Closing Date. Buyer shall be responsible for all
         chargebacks and rebates which are reported after 60 days following the
         Closing Date.

                  8.13. Confidentiality. The Confidentiality Agreement (the
         "Confidentiality Agreement") between F. Hoffman-La Roche Ltd and Buyer
         dated as of October 14, 1997, as it applies to Parent and its
         Affiliates, is hereby incorporated by reference into this Agreement.

                  8.14. Consents. Each of Parent, Sellers and Buyer agree to
         cooperate in good faith to obtain any consents from third parties
         relating to the assignment of existing contracts.

                  8.15. Cooperation on Safety Reports. Following the Closing
         Date for so long as Sellers and Buyer continue to market the Product,
         each of Sellers and Buyer agree promptly to provide the other party
         with all information received by it in connection with the occurrence
         of serious or unexpected events relating to the Product.

                  8.16. Manufacturing Improvements. Parent agrees that if,
         during the term of the Supply Agreement, the Roche Group implements any
         improvement in the manufacturing technology and know-how used in the
         manufacture of the Active Ingredient or the Product, it shall grant to
         Buyer a perpetual, paid-up, irrevocable, royalty-free, non-exclusive
         licence, with





                                      32
<PAGE>
 
         right to sub-licence, any such improvement for use in manufacture of
         the Active Ingredient or the Product for sale in the Territory.

                  Buyer agrees that if, during the term of the Supply Agreement,
         Buyer or its assignee implements any improvement in the manufacturing
         technology and know-how used in the manufacture of the Active
         Ingredient or the Product, it shall grant to the Roche Group a
         perpetual, paid-up, irrevocable, royalty-free, non-exclusive licence,
         with right to sub-licence, any such improvement for use in manufacture
         of the Active Ingredient or the Product for sale outside the Territory.

                  8.17. Importation. Each of Parent and Buyer agrees that,
         subject to applicable law, it will not actively support the importation
         of the Product into the Territory in the case of Parent and Sellers and
         outside the Territory in the case of Buyer.

                  8.18. Product Recall; Product Liability. Parent and Buyer
         agree that in the event prior to the Closing Date of a major recall of
         the Product or the occurrence of material product liability issues in
         connection therewith which affect the viability of the Business, Parent
         and Buyer will negotiate in good faith with respect to an adjustment of
         the Purchase Price.

                  8.19. Confirmation of Financing. Upon the written request by
         Parent at any time and from time to time, (a) Buyer shall use its best
         efforts to obtain (and deliver to Parent within 5 business days after
         such request) a waiver by Morgan Stanley in the form set forth in
         Exhibit C hereto, in favor of Buyer, of any right to terminate the
         Commitment Letter or to assert that any condition to Morgan Stanley's
         obligations under the Commitment Letter has not been satisfied at the
         time of such waiver, based upon facts and circumstances at the time of
         such waiver which are publicly known or, after due inquiry by Morgan
         Stanley, known to Morgan Stanley and (b) in the event Morgan Stanley
         fails or refuses to provide such waiver within such period, Buyer shall
         deliver to Parent within 6 business days after such request a full
         written explanation of such failure or refusal and the reasons
         therefor.

9.       MANUFACTURING

                  9.1. Supply Agreement. Consistent with the terms of the
         Agreement Containing Consent Order, on or prior to the Closing Date,
         Parent and Buyer or their Affiliates shall enter into the Supply
         Agreement for the supply of the Product (as that term is defined in
         Section 1.3 of the Supply Agreement) substantially in the form attached
         hereto as Exhibit B.




                                      33
<PAGE>
 
                  9.2.  Parent's Representations and Warranties for its
         Supplies. As provided in the Supply Agreement:

                  Parent shall make representations and warranties to Buyer that
         the bulk labelled lyophilized vials or bulk Active Ingredient that is
         manufactured by the Roche Group (including without limitation the BM
         Group companies) for Buyer pursuant to the Supply Agreement meets the
         FDA and DHC approved specifications therefor. Parent shall agree to
         indemnify, defend and hold Buyer harmless from any and all suits,
         claims, actions, demands, liabilities, expenses or losses that may be
         alleged to result from the failure of the bulk labelled lyophilized
         vials or bulk Active Ingredient manufactured by the Roche Group for
         Buyer pursuant to the Supply Agreement to meet FDA and DHC
         specifications. This obligation shall be contingent upon Buyer giving
         Parent prompt, adequate notice of such claim, cooperating fully in the
         defence of such claim, and permitting Parent to assume the sole control
         of all phases of the defence and/or settlement of such claim, including
         the selection of counsel. This obligation shall not require Parent to
         be liable for any negligent act or omission of Buyer or for any
         representations and warranties, express or implied, made by the Buyer
         that exceed the representations and warranties made by Parent to Buyer.

                  9.3.  Technology Transfer. To the extent Buyer undertakes the
         manufacture of the Product in the Territory and subject to the
         obligations under the Supply Agreement, upon reasonable notice and
         request from Buyer, the Roche Group (including without limitation the
         BM Group companies) shall provide to Buyer or a third party contract
         manufacturer designated by Buyer in a timely manner: (a) for a period
         not to exceed four years following the Closing Date, assistance and
         advice to enable Buyer or a third party contract manufacturer
         designated by Buyer to obtain all necessary approvals to manufacture
         the Product for sale in the Territory; (b) for a period not to exceed
         one (1) year from the date of such approvals, assistance to enable
         Buyer or a third party contract manufacturer designated by Buyer to
         manufacture the Product in substantially the same manner and quality
         employed or achieved by Sellers as of the date Buyer obtains such
         approvals; and (c) until the date of such approvals (or earlier if
         Buyer abandons its efforts to obtain such approvals), consultation with
         knowledgeable employees of the Roche Group and training at the request
         of and at the manufacturing facility of Buyer or a third party contract
         manufacturer designated by Buyer (or of the Buyer's choosing),
         sufficient to satisfy the management of Buyer that its personnel (or
         the personnel of a third party contract manufacturer

                                      34
<PAGE>
 
         designated by Buyer) are adequately trained in the manufacture of the
         Product for sale in the Territory. Such assistance shall include
         on-site inspections, at Buyer's request, of the facility that is
         producing the Active Ingredient for supply under the Supply Agreement.
         Parent shall be entitled to reimbursement from Buyer for all the Roche
         Group's direct out-of-pocket expenses incurred in providing the
         services and assistance described above. Buyer shall be responsible for
         the construction of the facilities associated with the manufacture of
         the Product.

              9.4.   Approvals. In the manner and form required by the Agreement
         Containing Consent Order, Buyer shall submit to the FTC a certification
         attesting to the good faith intention of Buyer, including a plan of
         Buyer, to obtain in an expeditious manner all necessary approvals to
         manufacture the Product for sale in the Territory. Furthermore, in
         accordance with the terms of the Agreement Containing Consent Order,
         Buyer shall submit to the trustee appointed pursuant to the Agreement
         Containing Consent Order, periodic verified written reports setting
         forth in detail the efforts of Buyer to sell the Product obtained
         pursuant to the Supply Agreement in the United States and to obtain all
         approvals necessary to manufacture the Product for sale in the
         Territory. The first such report shall be submitted within sixty (60)
         days from the date this Agreement is approved by the FTC and every
         ninety (90) days thereafter until all necessary approvals are obtained
         by Buyer for manufacturer of the Product for sale in the Territory.
         Buyer shall also report to the FTC and the trustee referred to above
         within ten (10) days of its ceasing the sale in the United States of
         the Product obtained pursuant to the Supply Agreement for any time
         period exceeding sixty (60) days or abandoning its efforts to obtain
         all necessary approvals to manufacture the Product for sale in the
         Territory.

10.      CONDITIONS PRECEDENT TO CLOSING

             10.1.   Conditions to Obligations of Buyer and Parent. The
         obligations of Buyer and Parent to complete the transactions
         contemplated hereby are subject to the satisfaction on or prior to the
         Closing Date of the following conditions:

             10.1.1. No provision of any applicable law or regulation and no
         judgement, injunction, order or decree shall prohibit the consummation
         of the Closing.

             10.1.2. Agreement Containing Consent Order. The Agreement
         Containing Consent Order (in the form provided to Buyer) shall have
         been

                                      35
<PAGE>
 
         accepted for public comment by the FTC, and the transactions
         contemplated by this Agreement shall be permitted under the terms of
         the Agreement Containing Consent Order.

             10.1.3.  To the extent required by law or as deemed advisable by
         the parties, an Advance Ruling Certificate under section 102 of the
         Competition Act (Canada) shall have been issued for the transaction
         contemplated by this Agreement or the waiting period under section 123
         of the Competition Act (Canada) shall have been expired and advice in
         writing by the Director shall have been received that he has determined
         not to make an application for an order under section 92 or 100 of the
         Competition Act (Canada) or to commence an inquiry under section 10 of
         the Competition Act (Canada) and the transaction contemplated by this
         Agreement shall have obtained of any approvals under the Investment
         Canada Act if required; provided that if all other conditions shall
         have been satisfied, Parent and Buyer agree to close that portion of
         the transaction pertaining to the United States prior to the
         satisfaction of the conditions set forth in this Section and to close
         that portion of the transaction pertaining to Canada at such later
         date, and on terms and conditions, as mutually agreed.

             10.1.4.  The Corange Transaction shall have been consummated in
         accordance with the terms of the Stock Purchase Agreement.

             10.1.5.  Any applicable waiting period under the HSR Act relating
         to the transactions contemplated hereby shall have expired or been
         terminated.

             10.2.    Conditions to Obligations of Buyer. The obligation of
         Buyer to complete the transactions contemplated hereby is subject to
         the satisfaction on or prior to the Closing Date of the following
         conditions (all or any of which may be waived in whole or in part by
         Buyer);

             10.2.1.  Representations and Warranties. The representations and
         warranties made by Parent in this Agreement shall have been true and
         correct (without regard to materiality or Material Adverse Effect
         qualifications set forth therein) as of the Closing Date with the same
         force and effect as though said representations and warranties had been
         made on the Closing Date, except for representations and warranties
         made as of a specified date, which will be true and correct in all
         respects as of the specified date, and except for breaches of any such
         representations or warranties that would not have, individually or in
         the aggregate, a Material Adverse Effect. Each Seller shall have
         delivered to Buyer at Closing a

                                      36
<PAGE>
 
         representation and warranty that each of Parent's representations and
         warranties in Section 4 with respect to such Seller were true and
         correct as of the date thereof, and such representation and warranty
         shall be true and correct as of the Closing Date except for breaches
         that would not have, individually or in the aggregate, a Material
         Adverse Effect.

             10.2.2.  Performance. Parent shall have performed and complied in
         all material respects with all agreements, obligations and conditions
         required by this Agreement to be so performed or complied with by it
         prior to or at Closing.

             10.3.    Conditions to Obligations of Parent. The obligation of
         Parent to complete the transactions contemplated hereby is subject to
         the satisfaction on or prior to the Closing Date of the following
         conditions (all or any of which may be waived in whole or in part by
         Parent):

             10.3.1.  Representations and Warranties. The representations and
         warranties made by Buyer in this Agreement shall have been true and
         correct in all material respects as of the Closing Date with the same
         force and effect as though said representations and warranties had been
         made on the Closing Date (except for representations and warranties
         made as of a specified date, which will be true and correct in all
         respects as of the specified date).

             10.3.2.  Performance. Buyer shall have performed and complied in
         all material respect with all agreements, obligations and conditions
         required by this Agreement to be so performed or complied with by it
         prior to or at Closing.

                                      37
<PAGE>
 
11.      THE CLOSING

            11.1.   The Closing. Subject to the satisfaction of all of the
         conditions to each party's obligations set forth in Section 10 hereof
         (or, with respect to any condition not satisfied, the waiver in writing
         thereof by the party or parties for whose benefit the condition exists)
         and subject to Section 12.1.2, the closing of the transactions
         contemplated by this Agreement (the "Closing") shall take place at 9
         a.m. (local time) on the first business day which is at least 30 days
         following public announcement of this Agreement (assuming the last
         condition precedent under Section 10 herein above has been fulfilled)
         or earlier or later, if mutually agreed by the parties, in accordance
         with the Agreement Containing Consent Order and any applicable law or
         regulation (the "Closing Date") at the offices of Parent in Hamilton,
         Bermuda. The transfer of the Assets shall be deemed to have occurred as
         of 0.01 a.m. of the Closing Date.

            11.2.   Deliveries by Parent.  At Closing, Parent shall deliver or
         cause to be delivered to Buyer:

            11.2.1. the conveyance, assignment, and assumption agreement with
         respect to the Assets and the Assumed Agreements and all obligations
         and responsibilities associated therewith;

            11.2.2. the assignments of the Patents and Trademarks as set forth
         in Section 8.1;

            11.2.3. the assignments of the Registrations as set forth in Section
         8.2;

            11.2.4. the Supply Agreement;

            11.2.5. the Transition Services Agreement;

            11.2.6. the Inventory and the statement of the quantity of the
         Inventory as set forth in Section 2.12;

            11.2.7. to the extent available and practicable, hard copies of the
         documents as set forth in Section 2 herein above; all such documents,
         which cannot be delivered to Buyer at Closing, shall be delivered by
         Parent to Buyer as soon as practicable after Closing;

            11.2.8. except as otherwise provided herein, such agreements,
         licences, notices, and authorisations as may be necessary and
         sufficient to

                                      38
<PAGE>
 
         permit Buyer to use or operate under the Registrations (if legally
         permissible) and Know-How and that Buyer has requested from Parent;

             11.2.9.   a receipt for the Purchase Price; and

             11.2.10.  the licences or sublicences set forth in Sections 2.2,
         2.3, 2.7, 2.8 and 2.16.

             11.3.     Deliveries by Buyer. At Closing, Buyer shall deliver or
         cause to be delivered to Parent:

             11.3.1.   the Purchase Price payable in accordance with Section
         3.1; and

             11.3.2.   the conveyance, assignment and assumption agreement with
         respect to the Assets and the Assumed Agreements and all obligations
         and responsibilities associated therewith;

             11.3.3.   the Supply Agreement; and

             11.3.4.   the Transition Services Agreement;

             11.4.     Effects of Closing. Upon Closing the ownership of the
         Assets as well as the full responsibility for the use of the Assets and
         the conduct of the Business comprising the use of the Assets shall pass
         from Sellers to Buyer. Sellers shall remain exclusively responsible for
         the conduct of the Business prior to Closing (including any
         consequences therefrom which may appear after the Closing). Buyer shall
         be exclusively responsible for the conduct of the Retavase Business
         from Closing. Buyer acknowledges that as per the Closing the product
         liability insurance of Sellers will terminate on the Closing Date and
         Buyer shall be responsible for proper insurance of the product
         liability and other risks relating to the Retavase Business. The
         Closing shall further have the other effects provided for in this
         Agreement.

12.      TERMINATION

             12.1.     Termination.  This Agreement and the transactions
         contemplated hereby may be terminated at any time prior to the Closing
         Date:

             12.1.1.   By the mutual written consent of Parent and Buyer;

                                      39
<PAGE>
 
             12.1.2.   By either Parent or Buyer if Closing shall not have
         occurred on or before April 20, 1998; or

             12.1.3.   By either Parent or Buyer if consummation of the
         transactions contemplated hereby shall violate any non-appealable final
         order, decree or judgement of any court or governmental body having
         competent jurisdiction.

             12.1.4.   By either Parent or Buyer if there has been a material
         violation or breach by the other party of any of the agreements,
         representations or warranties contained in this Agreement that has not
         been waived in writing, or if there has been a material failure of
         satisfaction of a condition to the obligations of the other party that
         has not been waived in writing, and such violation, breach, or failure
         has not been cured within fifteen (15) days (but in no event later than
         April 20, 1998) of written notice to the other party; or

             12.2.     Effect of Termination. If this Agreement is terminated
         pursuant to this Section 12, all obligations of Parent and Buyer under
         this Agreement shall terminate without further liability of Parent or
         Buyer except (a) for the obligations of Buyer and Parent under Sections
         8.13, 15, and 16.2; and (b) that such termination shall not constitute
         a waiver by any party of any claim it may have for damages caused by
         reason of a breach by the other party of a representation, warranty,
         covenant or agreement.

             12.3.     Termination by the FTC. (a) As set forth in Paragraph
         II.B.9 of the Agreement Containing Consent Order, the FTC may terminate
         this Agreement if Buyer: (i) voluntarily ceases for sixty (60) days or
         more the sale in the United States of, or otherwise fails to pursue
         good faith efforts to sell, the Product obtained pursuant to the Supply
         Agreement prior to obtaining all necessary FDA approvals to manufacture
         its own Product for sale in the United States; (ii) fails to pursue
         good faith efforts to obtain all necessary FDA approvals to
         manufacture, or have manufactured by third parties other than Parent or
         its Affiliates, its own Product for sale in the United States; or (iii)
         fails to obtain all such FDA approvals within four (4) years from the
         date the FTC grants final approval to the Agreement Containing Consent
         Order; provided, however, that this time period may be extended as
         provided in Paragraph II.B.9 of the Agreement Containing Consent Order.
         If this Agreement is terminated in accordance with the provisions of
         this section, the Assets shall revert back to Sellers and shall be
         divested in the manner provided in Paragraph IV of the Agreement
         Containing Consent Order.

                                      40
<PAGE>
 
                  (b)   In the event the FTC withdraws its acceptance of the
         Agreement Containing Consent Order after expiration of the sixty (60)
         day public comment period referred to in paragraph 4 of the Agreement
         Containing Consent Order, this Agreement shall forthwith become null
         and void and the Buyer shall immediately transfer back to Sellers all
         assets, properties and rights conveyed to it hereunder and, upon
         receipt of said assets, properties and rights, Sellers shall pay to
         Buyer the Purchase Price. Buyer agrees that (i) during the pendency of
         the sixty (60) day public comment period it shall, subject to its sale
         of inventory purchased under the Supply Agreement, preserve intact all
         assets, properties and rights conveyed to it hereunder and shall take
         no action that would individually or in the aggregate have a material
         adverse effect on those assets and (ii) Buyer and its Affiliates will
         not disclose any confidential information concerning the Retavase
         Business; provided that information shall not be deemed to be
         confidential that Buyer can prove (A) was in the public domain prior to
         the date of this Agreement or thereafter enters the public domain
         through no fault of Buyer, its Affiliates or their respective
         representatives, (B) was available to Buyer on a non-confidential basis
         prior to its disclosure to Buyer by Parent, Sellers, their Affiliates
         or their respective representatives, (C) is later lawfully acquired by
         Buyer from sources other than Parent, Sellers, their Affiliates or
         their respective representatives who are not, to the best of knowledge
         of Buyer, subject to any legally binding obligation to keep such
         information confidential, or (D) independently developed by Buyer
         without reference to confidential information covered hereunder.

13.      SURVIVAL; REMEDIES; CLAIMS; INDEMNIFICATION

                13.1.   Remedy for Breach. After the Closing, the sole and
         exclusive remedy of Buyer and Parent for any breach or inaccuracy of
         any representation or warranty under this Agreement by the other party
         hereto or by Sellers shall be the remedies contained in this Section 13
         and shall be enforceable only as provided in Section 15.1. Any claims
         that a party may have arising out of the other party's or Sellers'
         breach of its representations and warranties hereunder shall be
         notified to the other party no later than 12 (twelve) months following
         Closing (without affecting either party's right to start arbitration
         proceedings in accordance with Section 15.1 thereafter if the
         notification for the pertaining matter has been given prior to the
         expiration of such 12 month period). Parent and Buyer agree to use all
         reasonable efforts to mitigate any loss or damage for which they may
         seek a remedy under this Article 13.

                13.2.   Indemnification by Parent.

                                      41
<PAGE>
 
                13.2.1. Claims. Subject to the limitations set forth in Section
         13.2.2, Parent shall indemnify Buyer and its Affiliates against and
         agrees to hold Buyer and its Affiliates harmless from any and all
         damage, loss, liability, third party claims, and expense (collectively,
         "Damages") (including, without limitation, reasonable expenses of
         investigation and attorneys' fees and expenses in connection with any
         action, suit or proceeding brought against Buyer or its Affiliates)
         incurred or suffered by Buyer or its Affiliates arising out of (a) any
         breach of a representation or warranty or covenant made by Parent or
         Sellers herein, (b) the maintenance of the Assets by Sellers prior to
         Closing or (c) the conduct of the Business by Parent or its Affiliates
         prior to Closing (collectively, "Indemnifiable Claims").

                13.2.2. Limitations. Notwithstanding anything to the contrary
         set forth elsewhere herein, Buyer and its Affiliates shall not be
         entitled to indemnification hereunder with respect to any Indemnifiable
         Claim for breaches of representations and warranties asserted pursuant
         to Section 13.2.1(a) unless the amount of Damages with respect to such
         Indemnifiable Claim exceeds US$500,000. However, Parent shall in no
         event be required to pay Buyer and its Affiliates more than 33% of the
         Purchase Price in respect of aggregate Damages for Indemnifiable Claims
         for breaches of representations and warranties asserted pursuant to
         Section 13.2.1(a).

                13.3.   Indemnification by Buyer. Buyer shall indemnify Parent
         and its Affiliates (including without limitation the BM Group
         companies) against and agrees to hold Parent and its Affiliates
         harmless from any and all Damages (including without limitation
         reasonable expenses of investigation and attorneys' fees and expenses
         in connection with any action, suit or proceeding brought against
         Parent or its Affiliates) incurred or suffered by Parent or its
         Affiliates arising out of (a) any breach of a representation or
         warranty or covenant made by Buyer herein; (b) the conduct of the
         Retavase Business by Buyer and its Affiliates from Closing or (c) the
         use of the licences granted pursuant to Section 2.16 of this Agreement
         (collectively, "Indemnifiable Claims"). Notwithstanding anything to the
         contrary set forth elsewhere herein, Parent and its Affiliates shall
         not be entitled to indemnification hereunder with respect to any
         Indemnifiable Claim for breaches of representations and warranties
         asserted pursuant to this Section 13.3 unless the amount of Damages
         with respect to such Indemnifiable Claim exceeds US$ 500,000, provided
         that such limitation shall not apply to a breach by Buyer in connection
         with Buyer's obligations pursuant to Sections 3.1 and 3.3.

                                      42
<PAGE>
 
                13.4.   Notice. A party seeking indemnification or to be held
         harmless pursuant to Section 13.2 or 13.3 (an "Indemnified Party")
         shall give prompt notice to the party from whom such relief is sought
         (the "Indemnifying Party") of the assertion of any claim, or the
         commencement of any action, suit or proceeding, in respect of which
         relief is or may be sought hereunder (whether or not the limits set
         forth in Section 13.2.2 and Section 13.3 have been exceeded) and will
         give the Indemnifying Party such information with respect thereto as
         the Indemnifying Party may reasonably request, but failure to give such
         notice shall not relieve the Indemnifying Party of any liability
         hereunder (except to the extent the Indemnifying Party has suffered
         actual prejudice thereby).

                13.5.   Participation in Defence. The Indemnifying Party may, at
         its expense, participate in or assume the defence of any such action,
         suit or proceeding involving a third party. In such case the
         Indemnified party shall have the right (but not the duty) to
         participate in the defence thereof, and to employ counsel, at its own
         expense, separate from counsel employed by the Indemnifying Party in
         any such action and to participate in the defence thereof. The
         Indemnifying Party shall be liable for the fees and expenses of one
         firm as counsel (and appropriate local counsel) employed by the
         Indemnified Party if the Indemnifying Party has not assumed the defence
         thereof. Whether or not the Indemnifying Party chooses to defend or
         prosecute any claim involving a third party, all the parties hereto
         shall, and shall cause their respective Affiliates to, cooperate in the
         defence or prosecution thereof and shall furnish, or cause to be
         furnished, such records, information and testimony, and attend such
         conferences, discovery proceedings, hearings, trials and appeals, as
         may be reasonably requested in connection therewith.

                13.6.   Settlements. The Indemnifying Party shall not be liable
         under this Section for any settlement effected without its consent of
         any claim, litigation or proceedings in respect of which relief may be
         sought hereunder, unless the Indemnifying Party refuses to acknowledge
         liability for indemnifying or holding the Indemnified Party harmless
         under this Section 13 and/or declines to defend the Indemnified Party
         in such claim, litigation or proceeding.

                13.7.   Other Claims. In the event that any third party
         (including Genentech) commences (in the Territory or in Germany) a
         patent infringement action (with respect to a patent that has been
         issued or a patent application that has been published as of the date
         hereof) with respect to the Product in the Territory, Buyer shall be
         solely responsible

                                      43
<PAGE>
 
         for the control of the defence of such action and Buyer further
         covenants to undertake, in good faith, the full and complete defence of
         any such action. Buyer shall not abandon or make any concessions in the
         defence of such patent suits which affect Parent's or its Affiliates'
         ability to manufacture or sell the Active Ingredient or any product
         made therewith outside the Territory or any other products or research
         or development projects in or outside the Territory. Parent shall
         reimburse Buyer with respect to such actions in the same manner and to
         the same extent as set forth in Section 3.4 hereof, provided, that (i)
         if the action has been instituted by Genentech, Inc. or a subsidiary or
         licensee of Genentech, Inc., Parent shall not be obligated to make any
         payment to Buyer as a result of any settlement thereof unless such
         settlement is commercially reasonable for Buyer under the circumstances
         in absence of Parent's reimbursement obligations pursuant to this
         Section 13.7 and (ii) in the case of any other action, Parent shall not
         be obligated to make any payment to Buyer as a result of any settlement
         thereof unless in the judgement of Parent such settlement is reasonable
         under the circumstances.

14.      NOTICES

         Any notice required or permitted to be given hereunder shall be deemed
         sufficient if sent by facsimile letter or overnight courier, or
         delivered by hand to Parent or Buyer at the respective addresses and
         facsimile numbers set forth below or at such other address and
         facsimile number as either party hereto may designate. If sent by
         facsimile letter, notice shall be deemed given when the transmission is
         completed if the sender has a confirmed transmission report and if the
         sender has sent a confirmation copy by registered mail. If a confirmed
         transmission report does not exist, then the notice will be deemed
         given when the notice is actually received by the person to whom it is
         sent. If delivered by overnight courier, notice shall be deemed given
         when it has been signed for. If delivered by hand, notice shall be
         deemed given when received.

         If to Buyer, to:

         Centocor, Inc.
         200 Great Valley Parkway
         Malvern, PA 19355-1307
         Attention: Corporate Secretary
         Fax: 610-651-6331

                                      44
<PAGE>
 
         if to Parent, to:

         Roche Healthcare Limited
         P.O. Box HM 905
         Hamilton HM DX
         Bermuda
         Attention: President
         Fax: ++1 441 295-4165

         with a copy to:

         F. Hoffmann-La Roche Ltd
         CH-4070 Basel, Switzerland
         Attention: Corporate Law Department
         Fax: ++41 61 688 1396

15.      ARBITRATION AND GOVERNING LAW

                15.1.   Except for the right of either party to apply to a court
         of competent jurisdiction for a temporary restraining order to preserve
         the status quo or prevent irreparable harm pending the selection and
         confirmation of a panel of arbitrators, any dispute, controversy, or
         claims arising under, out of or relating to this Agreement (and
         subsequent amendments thereof), its valid conclusion, binding effect,
         interpretation, performance, breach or termination, including tort
         claims, shall be referred to and finally determined by arbitration, to
         the exclusion of any courts of law, in accordance with the Rules of
         Arbitration of the International Chamber of Commerce as in force at the
         time when initiating the arbitration. The arbitral tribunal shall
         consist of three arbitrators. The place of arbitration shall be
         Hamilton, Bermuda. The language to be used in the arbitral proceedings
         shall be English. The arbitration decision shall be final and binding
         upon the parties and the parties agree that any award granted pursuant
         to such decision may be entered forthwith in any court of competent
         jurisdiction. This arbitration clause and any award rendered pursuant
         to it shall be governed by the United Nations Convention on the
         Recognition and Enforcement of Foreign Arbitration Awards signed in New
         York as of 10 June, 1958. The party to whom a favourable ruling is
         awarded shall be entitled to reimbursement of all its reasonable costs
         and expenses in arbitration by the other party.

                15.2.   The present Agreement shall be subject to the
         substantive law of Bermuda (regardless of its or any other
         jurisdiction's choice of law principles).

                                      45
<PAGE>
 
16.      ADDITIONAL TERMS

                16.1.   Brokers. Buyer represents to Parent that it has not
         employed any investment banker, broker, finder or intermediary in
         connection with the transactions contemplated hereby who might be
         entitled to a fee or any commission from Parent upon consummation of
         the transactions contemplated hereby. Parent represents to Buyer that
         it has not employed any such person in connection with the transactions
         contemplated hereby who might be entitled to a fee or any commission
         from Buyer upon consummation of the transactions contemplated hereby.

                16.2.   Expenses, Taxes and Fees. Except as otherwise expressly
         provided in this Agreement, all legal, accounting and other costs and
         expenses incurred in connection herewith and the transactions
         contemplated hereby shall be paid by the party incurring such costs and
         expenses. Any possible value added, excise or transfer taxes or merger
         control filing fees or similar filing fees levied in connection with
         the present Agreement shall be paid and borne solely by Buyer and are
         not included in the Purchase Price or the payment for the inventory
         according to Section 3.

                16.3.   Entire Agreement. This Agreement, the Exhibits, the
         Schedules (including Disclosure Schedule), and the Confidentiality
         Agreement embody the entire agreement of the parties hereto with
         respect to the subject matter hereof and supersede and replace all
         previous negotiations, understandings, representations, writings, and
         contract provisions and rights relating to the subject matter hereof.

                16.4.   Successors and Assigns. This Agreement shall be binding
         upon and shall inure to the benefit of the parties and their respective
         successors and assigns; provided that this Agreement may not be
         assigned by any party without the written consent of the other party.

                16.5.   Amendments; No Waiver. No provision of this Agreement
         may be amended, revoked or waived except by a writing signed and
         delivered by an authorised officer of each party. No failure or delay
         on the part of either party in exercising any right hereunder will
         operate as a waiver of, or impair, any such right. No single or partial
         exercise of any such right will preclude any other or further exercise
         thereof or the exercise of any other right. No waiver of any such right
         will be deemed a waiver of any other right hereunder.

                                      46
<PAGE>
 
                16.6.   Counterparts. This Agreement may be executed in one or
         more counterparts all of which shall together constitute one and the
         same instrument and shall become effective when a counterpart has been
         signed by Buyer and delivered to Parent and a counterpart has been
         signed by Parent and delivered to Buyer.
         
                16.7.   Captions. The captions herein are included for
         convenience of reference only and shall be ignored in the construction
         or interpretation hereof.

         IN WITNESS WHEREOF, this Agreement has been signed by duly authorised
representatives of each of the parties hereto as of the date first above
written.

Roche Healthcare Limited                    Centocor, Inc.



By /s/ John R. Talbot                       By  /s/ David P. Holveck
   ---------------------------                  --------------------------- 
Name  John R. Talbot                        Name  David P. Holveck
     -------------------------                   --------------------------  
Title: President                            Title: Chief Executive Officer
      ------------------------                    -------------------------


                                      47
<PAGE>
 
List of Exhibits
----------------
                                      48
<PAGE>
                                                                  Exhibit 10.35 

                                                                  Exhibit A
                                                                  ---------


                         TRANSITION SERVICES AGREEMENT


     THIS TRANSITION SERVICES AGREEMENT (the "Agreement") is made and entered
into on ____________ ,1998 by and between Boehringer Mannheim Corporation
("Seller") on the one hand and Centocor, Inc. ("Buyer") on the other hand.

     WHEREAS Roche Healthcare Limited ("Parent") and Buyer have entered into an
Asset Purchase Agreement dated February 11, 1998 (the "Asset Purchase
Agreement") relating to RETAVASE (the "Product"), and

     WHEREAS the parties agree that Buyer or its Affiliates shall take over the
distribution of the Product as soon as possible when Buyer or its Affiliate has
obtained the pertaining necessary government approvals for the distribution of
the Product.  Parent and Buyer have agreed in the Asset Purchase Agreement that
Parent or its Affiliates shall provide certain transition services to Buyer or
its Affiliates for the Product under a transition services agreement for a
certain transition period after Closing.

Now, therefore the parties hereto agree as follows:

ARTICLE 1.     DEFINITIONS

1.1. "Affiliate" of a party means any corporation or other business entity
     controlled by, controlling or under common control with, such party. For
     this purpose "control" shall mean direct or indirect beneficial ownership
     of more than fifty percent (50%) of the voting or income interest in such
     corporation or other business entity; provided, however, Genentech, Inc.
     and its subsidiaries shall not be considered an Affiliate of Parent.

1.2. "Fully Loaded Costs" means all direct expenses and, with respect to time
     spent on a project by employees, an hourly rate which equals salary
     (including benefits) plus overhead allocated on the basis of time spent.

1.3. "Net Sales" means  gross sales occurring after the Closing Date after
     deduction of returns, distributor discounts, sales rebates (price
     reduction) and volume (quantity) discount as well as sales taxes (e.g.
     value added taxes) and other taxes directly linked to the sales (e.g.
     excise taxes) attributed to those sales.

                                       1
<PAGE>
 
1.4. "Services Fee" means a rate which equals 4% of Net Sales for the first
     month, 3% of Net Sales for the second month and 2% of Net Sales for the
     third month (and thereafter) following the Closing Date.

1.5. "Services" means any and all services with respect to the Product provided
     by Seller to Buyer pursuant to this Agreement.

1.6. "Territory" means the United States and Canada and respective possessions
     or territories.

1.7. Other Terms.    The term "Product" as well as other defined terms used
     herein and not defined above shall have the respective meanings assigned to
     such terms in the Asset Purchase Agreement.


ARTICLE 2.     RESPONSIBILITY OF PARTIES

2.1. Provision of Services.     Subject to the terms hereof, Seller and/or its
     designated Affiliate(s) shall (a) cooperate with Buyer or its Affiliate and
     assist in the orderly transition of the Business in the Territory to Buyer,
     and (b) provide the Services described herein that are requested by Buyer.

2.2. Cooperation and Assistance.     Seller or its designated Affiliate(s) shall
     make available knowledgeable employees/the individuals identified on
     Schedule I, or their qualified designees, for consultation with Buyer's
     representatives who shall be designated in writing to Seller via telephone,
     correspondence or in person at Seller's or its designated Affiliate's
     facilities for the purpose of conveying and transferring information
     relating to the operation of the Business in the Territory. Such
     consultation shall occur for reasonable periods of time upon reasonable
     notice during normal business hours. Seller may appoint substitutes for the
     individuals listed on Schedule I. Notwithstanding any other provision of
     this Agreement, the individuals listed on Schedule I (or their substitutes)
     shall be available for reasonable consultation but only for a period of six
     (6) months following Closing.

2.3. Distribution Agency Services.      With respect to the Product in the
     Territory, Seller or its designated Affiliate(s) shall provide all services
     (including warehousing and distribution, order taking, shipping, invoicing
     and collecting) customarily performed by a distribution agent and as
     currently conducted by Seller in connection with the sale of the Product in
     the Territory, including the following:

                                       2
<PAGE>
 
     (a) accepting orders and invoicing purchasers on behalf of Buyer;
     (b) processing all Product returned by customers in accordance with Section
         3 of this Agreement;
     (c) order entry and billing services;
     (d) recording sales and collecting amounts due in accordance with Section 4
         of this Agreement;
     (e) making appropriate payments for charge-backs and rebates subject to
         Section 3.1; and
     (f) customer complaint and inquiry services;

     it being understood that in providing such services Seller and/or its
     Affiliates shall continue to use certain tangible assets not transferred to
     Buyer at Closing including, without limitation, AUDIUS system, electronic
     mail, computer hardware and call reporting.

2.4. Customer Information. In order to inform customers of the transfer of
     the Business to Buyer, and otherwise transition same, Seller and/or its
     Affiliates and Buyer shall notify all contracted customers, trade customers
     and wholesalers of the transfer of the Product to Buyer by a method and at
     a time mutually agreed to by the parties. Notice to wholesalers  shall
     allow adequate transition time for the wholesalers. The parties hereby
     agree that Seller and its Affiliates shall not be responsible for providing
     Buyer with any sales or promotion support.

2.5. Government Contracts. The parties shall mutually agree on the timing and
     method of notifying applicable federal agency customers and the Health Care
     Financing Administration ("HCFA") of the sale of the Product to Buyer, and
     shall take whatever action is necessary to simultaneously add the Product
     to Buyer's federal supply schedule and Medicaid rebate agreement and delete
     the Product from the federal supply schedule and Medicaid rebate agreement
     of Seller or its Affiliates, as applicable.

2.6. Reports. Seller shall submit in writing to Buyer (i) within four (4)
     business days after the end of each month a report setting forth total
     Sales, and (ii) within fifteen (15) days after the end of each calendar
     month a report as set forth on Schedule II and such other information as
     Buyer shall reasonably request and that the BM Group had in place prior to
     the Closing Date.

2.7. NDC Numbers. Promptly following the Closing, Buyer shall take any and all
     action necessary to change the National Drug Code number for the Product,
     which change shall be implemented under Section 7.1 of the Asset Purchase
     Agreement; and if such number shall be obtained during the term of this
     Agreement, the 

                                       3
<PAGE>
 
     parties will discuss the appropriate implementation thereof with respect to
     the Services provided hereunder. Payments with respect to rebates shall be
     consistent with the Asset Purchase Agreement.

2.8. Payment of Net Sales.  Four days following the end of each month, Seller
     will wire transfer to Buyer an amount equal to total Net Sales collected
     for such month less the amount of the Services Fee portion of the fee
     calculated for such month under Section 5.2.

2.9. Medical Safety and Reporting. Following Closing, Buyer, will be responsible
     to provide all drug safety services for the Product in the Territory, such
     as handling medical and safety inquiries regarding the Product, receiving
     adverse event inquiries and report preparation, and the preparation and
     submission of two required quarterly reports, namely the Drug Safety
     Periodic Report and the Drug Safety Increased Frequency Report. Buyer
     represents to Seller that it will employ a trained physician to handle such
     inquiries and report preparation and filing. Following Closing, Seller and
     Buyer shall cooperate in good faith, as defined by the regulatory and drug
     safety reporting transition teams, to respond to all such questions, calls
     or inquiries.  Seller shall during the term of this Agreement forward
     medical safety information concerning the Products in the Territory
     received by Seller or its Affiliates to Buyer.


ARTICLE 3.     PRODUCT RETURNS

3.1. Returns.  The responsibility for Product returns in the Territory
     shall be governed by Section 8.11 of the Asset Purchase Agreement. During
     the term of this Agreement, Seller and its Affiliates process and pay all
     claims received by them for returns of Product in accordance with the
     provision of their return goods policy attached hereto as Schedule III.
     Buyer shall not engage in any action (other than pricing of the Product) to
     induce any purchaser of the Product to return Product sold prior to Closing
     Date; provided, however, that to the extent returns of Product result from
     changes in pricing by Buyer, Buyer shall be responsible for such returns.
     For Product shipped after the Closing Date, Buyer shall be responsible for
     all returns of the Product within the Territory. Buyer shall reimburse
     Seller and its Affiliates for all cost of returns handled by Seller and its
     Affiliates hereunder for which Buyer is responsible according to Section
     8.11 of the Asset Purchase Agreement.

3.2. Disposition of Returned Product.  Returned Product will be handled in
     accordance with the provisions of the disposition of returned goods policy

                                       4
<PAGE>
 
     Seller, a copy of which is attached hereto as Schedule IV.
 

ARTICLE 4.     ACCOUNTS RECEIVABLE

     So long as it continues to provide Services, Seller or its designated
     Affiliate(s) shall use reasonable efforts (except for instituting third
     party collection or legal proceedings) to collect accounts receivable with
     respect to the Product.


ARTICLE 5.     PAYMENTS

5.1. Fees.     In consideration of Seller's and its Affiliate(s) Services under
     this Agreement, Buyer will pay to Seller a fee equal to the Services Fee.
     In addition, Seller and its Affiliate(s) shall be reimbursed their Fully
     Loaded Costs for any extraordinary services (i.e., those services beyond
     those expected in the context of ordinary business operations) including
     without limitation the cost of destruction of returned goods other than
     pursuant to on-going, normal business operations and the participation of
     Seller and its Affiliates in any recall of Product, "scrap" charges
     incurred because of NDC or other labelling or packaging changes,
     transportation costs associated with the delivery of inventory and records
     upon termination of this Agreement and any other expenses incurred by
     Seller and its Affiliates specifically as a result of this Agreement.
     Buyer will reimburse Seller and its Affiliates with respect to the
     foregoing costs, if any, within thirty (30) days of receipt of Seller's
     statement.

5.2. Calculations.  As soon as practicable after the end of each calendar month,
     Seller and its Affiliates will calculate the total amount of fee payable by
     Buyer for such month under Section 5.1.


ARTICLE 6.     STANDARD FOR SERVICE

     Seller and its Affiliate(s) shall meet the standards of the applicable
     profession in performing Services hereunder; provided that neither Seller
     and its Affiliate(s) nor their employees shall have any liability to Buyer
     in connection with such performance absent bad faith, negligence or wilful
     misconduct. As a principle, the parties agree that the quality and quantity
     of Services provided hereunder to Buyer (including without limitation the
     substance, timeliness and diligence thereof) shall be substantially the
     same as the quality and quantity of services previously rendered in
     relation to the Product by BMC personnel. Nothing contained in this

                                       5
<PAGE>
 
     Agreement shall require Seller and its Affiliate(s) to alter its
     operations, policies, procedures, method of doing business, reporting
     mechanism or formats or information technology systems in order to provide
     Services hereunder or otherwise engage in any extraordinary activities,
     except as set forth in this Agreement. If Buyer suffers any loss or damage
     caused directly by the bad faith, negligence or wilful misconduct of
     Seller, its Affiliates or their employees hereunder, Buyer shall be
     entitled to recover its direct costs incurred. Under no circumstances shall
     Seller and its Affiliates have to pay or shall Buyer be entitled to recover
     any consequential, special, indirect or incidental damages hereunder.


ARTICLE 7.     TERM AND TERMINATION

7.1. Term. This Agreement shall commence as of the Closing date under the Asset
     Purchase Agreement and shall expire on the later of (i) 3 (three) months
     following the Closing Date and (ii) when Buyer or its Affiliate has
     obtained the pertaining necessary government approvals for the distribution
     of the Product in the country concerned, but in no event later than 6 (six)
     months after the Closing Date under the Asset Purchase Agreement. Buyer
     shall use best efforts to assume the Services provided by Seller and its
     Affiliates hereunder as soon as possible, whenever possible earlier than
     the expiry of this Agreement. If Buyer is, despite such best efforts,
     unable to assume the services being provided within the term of this
     Agreement, Buyer and Seller shall discuss in good faith solutions for the
     countries concerned.

7.2. Termination.     Either party may terminate this Agreement with immediate
     effect upon written notice (a) if the other party is in material breach or
     default with respect to any term or provision hereof and fails to cure the
     same within twenty-one (21) days of receipt of notice of said breach or
     default or (b) if the other party is or will inevitably in the near future
     be dissolved, liquidated or bankrupt. Buyer may terminate this Agreement at
     any time upon not less than ten (10) days written notice, provided any
     transition issues that will require cooperation after termination are
     mutually agreed to by the parties.

7.3. Rights and Duties of Parties Upon Termination.  Upon expiration or other
     termination of this Agreement in accordance with the terms hereof, the
     parties shall cooperate in the orderly termination of the Services
     hereunder, including without limitation the transfer of Product to Buyer;
     and the transfer of other information relating solely to the Product,
     including customer information.

                                       6
<PAGE>
 
ARTICLE 8.     CONFIDENTIALITY

     Seller and its Affiliates shall treat as confidential all information
     provided by Buyer hereunder, including but not limited to information
     relating to the Services. Buyer shall provide such information only to
     those employees of Seller and its Affiliates that require such information
     to effect the provisions of this Agreement. Seller shall not use such
     information except for the express purposes contemplated by this Agreement
     and shall not disclose such information to any individual or entity (except
     to such of its employees, Affiliates and subcontractors who reasonably
     require same for the purposes hereof and who are bound to Seller by like
     obligations as to confidentiality and non-use) without the express written
     permission of Buyer. Notwithstanding the foregoing, Seller shall not be
     prevented from using or disclosing any portion of such information that
     Seller can prove: (a) was in the public domain prior to the date of this
     agreement or thereafter enters the public domain through no fault of
     Seller, its Affiliates or their respective representatives; (b) was
     available to Seller on a non-confidential basis prior to its disclosure to
     Seller by Buyer, its Affiliates or their respective representatives; (c) is
     later lawfully acquired by Seller from sources other than Buyer, its
     Affiliates or their respective representatives who are not, to the best of
     knowledge of Seller, subject to any legally binding obligation to keep such
     information confidential; (d) independently developed by Seller without
     reference to such confidential information; or (e) is required by law,
     regulation, rule, act or order of any governmental authority or agency to
     be disclosed by Seller; provided, however, that in the case of (e), Seller
     gives Buyer sufficient advance written notice to permit Buyer to seek a
     protective order with respect to such information and thereafter Seller
     discloses only the minimum information required to be disclosed in order to
     comply. Should Seller and its Affiliates provide Buyer with any
     confidential information, or marked or confirmed in writing as confidential
     by Seller, relating to Seller's or its Affiliate(s) products or business,
     other than information which pertains to the Product or the Business, Buyer
     shall be subject to the confidentiality provisions under this Section 7.
     The obligations of each party under this Section shall remain in full force
     and effect for five (5) years following termination or expiration of this
     Agreement.


ARTICLE 9.     INDEPENDENT CONTRACTOR

     Each party shall act solely as an independent contractor and nothing in
     this Agreement shall be construed to give either the power or authority to
     enter into or incur, any commitments, expenses or liabilities whatsoever on
     behalf of the other party. Nothing herein shall be construed to create the
     relationship of partnership, 

                                       7
<PAGE>
 
     principal and agent, or joint venture between Buyer and Seller, other than
     as expressly set forth herein.


ARTICLE 10.   NOTICES

     Any notice required or permitted to be given hereunder shall be deemed
     sufficient if sent by facsimile letter or overnight courier, or delivered
     by hand to Seller or its designates Affiliate(s) or to Buyer at the
     respective addresses and facsimile numbers set forth below or at such other
     address and facsimile number as either party hereto may designate. If sent
     by facsimile letter, notice shall be deemed given when the transmission is
     completed if the sender has a confirmed transmission report. If a confirmed
     transmission report does not exist, then the notice will be deemed given
     when the notice is actually received by the person to whom it is sent. If
     delivered by overnight courier, notice shall be deemed given when it has
     been signed for. If delivered by hand, notice shall be deemed given when
     received.

     All correspondence to Seller shall be addressed as follows:

     Boehringer Mannheim Corporation
     101 Orchard Ridge Drive
     Gaithersburg, MD 20878
     Attention: Law Department
     Fax: 301-990-3815

     with a copy to:

     F.Hoffmann-La Roche Ltd
     CH-4070 Basel, Switzerland
     Attention: Corporate Law Department
     Fax: ++41 61 688 1396

                                       8
<PAGE>
 
          All correspondence to Buyer shall be addressed as follows:

          Centocor, Inc.
          200 Great Valley Parkway
          Malvern, PA 19355-1307
          Attention: Corporate Secretary
          Fax: 610-651-6331

ARTICLE 11.    SUCCESSORS AND ASSIGNS

          This Agreement shall be binding upon and shall inure to the benefit of
          the parties and their respective successors and assigns; provided that
          this Agreement may not be assigned by any party without prior written
          consent of the other party except that Seller may assign this
          Agreement to one or more of its Affiliates with the prior written
          consent of Buyer, which consent shall not be unreasonably withheld.

ARTICLE 12.    ADDITIONAL TERMS

12.1.     Arbitration and Governing Law. Any dispute, controversy or claim
          arising out of or relating to this Agreement shall be settled by final
          and binding arbitration in accordance with the arbitration provisions
          and the governing law of the Asset Purchase Agreement.

12.2.     Entire Agreement. This Agreement, along with the Asset Purchase
          Agreement, constitutes the entire understanding between the parties
          with respect to the subject matter hereof and supersedes and replaces
          all previous negotiations, understandings, representations, writings,
          and contract provisions and rights relating to the subject matter
          hereof. If there is any conflict between this Agreement and the terms
          and conditions contained on any purchase order or invoice, the terms
          and conditions of this Agreement shall prevail.

12.3.     Amendments; No Waiver. No provision of this Agreement may be amended,
          revoked or waived except by a writing signed and delivered by an
          authorized officer of each party. No failure or delay on the part of
          either part in exercising any right hereunder will operate as a waiver
          of, or impair, any such right. No single or partial exercise of any
          such right will preclude any other or further exercise thereof or the
          exercise of any other right. No waiver of any such right will be
          deemed a waiver of any other right hereunder.

12.4.     Validity. Should any part or provision of this Agreement be held
          unenforceable or invalid, the invalid or unenforceable provision shall
          be replaced with a provision

                                       9
<PAGE>
 
      that accomplishes, to the extent possible, the original business purpose
      of such provision in a valid and enforceable manner, and the remainder of
      this Agreement shall remain binding upon the parties.

12.5. Counterparts.  This Agreement may be executed in one or more counterparts,
      each of which shall be deemed to be an original, but all of which together
      shall constitute a single agreement.

      IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the day and year first hereinabove written.


Boehringer Mannheim Corporation     Centocor, Inc.



By                              By
  -------------------------       ---------------------------
Name                            Name                          
    -----------------------         -------------------------
Title:                          Title: 
      ---------------------           -----------------------

                                       10
<PAGE>
 
                                  SCHEDULE I


                                SELLER CONTACTS

<TABLE>
<CAPTION>
                                                   Key Contacts:

                                            Primary              Secondary
                                            -------              ---------
<S>                                     <C>              <C>
Overall questions of policy on major
unresolved issues

General operational questions             Barry Buzogany     Emile Williams     
                                                                                
Legal                                     Barry Buzogany     Donate Garoner     
                                                                                
Sales and marketing                       Jesus Leal         Jim Lennertz       
                                                                                
Contracts                                 Dave Martinez      Kathy Jarber       
                                                                                
Production planning/specific orders       Phil Rothchild     Veronica Starks    
                                                                                
Accounting/Finance                        Emile Williams     Kirk Barton        
                                                                                
Inventory                                 Phil Rothchild     Vic Pascoe         
                                                                                
Distribution                              Vic Pascoe         Phil Rothchild     
                                                                                
Records transfer/retention                Barry Buzogany     Donate Garoner     
                                                                                
Regulatory                                Julie Zimmerman    Chris Pannunzio    
                                                                                
Medicaid                                  Kirk Barton        Kathy Jarber       
                                                                                
Clinical Studies                          Stephan Fischer    Hugo Morales       
                                                                                
Medical Affairs                           Stephen Ohimor     Hugo Morales       
                                                                                
Quality Assurance/Quality Control         Lyn Olson          Karl-Wilhem Schultze
</TABLE>


<PAGE>
 
                                  SCHEDULE II


                               REPORTING FORMAT

<TABLE>
<CAPTION>
                                                  $ Amount  Units    Average
                                                                     price or cost
<S>                                               <C>       <C>      <C>
SALES:
Gross Sales
(by NDC for finished product or by product for
 bulk active)
 
Adjustments to gross sales:
 
Sales returns and allowances (by NDC)
 
Managed Care Rebates
(by NDC)
 
Medicaid Rebates
(by NDC)
 
Charge-backs (by NDC)
 
FINISHED GOOD INVENTORY
 
Beginning Balance
(by NDC)
 
Production (by NDC), @ agreed upon unit cost)
 
Cost of Sales (by NDC)
 
Ending Balance (by NDC)
</TABLE>


<PAGE>
 
                                                                   EXHIBIT 10.36

                                                                     Exhibit B
                                                                     ---------



                                SUPPLY AGREEMENT


       THIS SUPPLY AGREEMENT (this "Agreement") is made and entered into on
_____, 1998 by and between Boehringer Mannheim GmbH ("Seller") on the one hand
and Centocor, Inc. ("Buyer") on the other hand.

       WHEREAS Roche Healthcare Limited ("Parent") and Buyer have entered into
an Asset Purchase Agreement dated February 11, 1998 (the "Asset Purchase
Agreement") relating to RETAVASE (the "Product"), and

       WHEREAS Parent and Buyer have agreed in the Asset Purchase Agreement that
Seller and/or its Affiliates shall supply bulk labelled lyophilized vials or
bulk Active Ingredient to Buyer or its Affiliate for a period of four years and
at certain terms and conditions to be set forth in more detail in the present
Supply Agreement;

       Now, therefore, the parties hereto agree as follows:

1.     DEFINITIONS

1.1.   "Active Ingredient" means recombinant reteplase (rPA), a recombinant, 
       non-glycosylated plasminogen activator containing amino acids 1-3 and 
       176-527 of the amino acid sequence of tissue-type plasminogen activator.

1.2.   "Affiliate" of a party means any corporation or other business entity
       controlled by, controlling or under common control with, such party. For
       this purpose "control" shall mean direct or indirect beneficial ownership
       of more than fifty percent (50%) of the voting or income interest in such
       corporation or other business entity; provided, however, Genentech, Inc.
       and its subsidiaries shall not be considered an Affiliate of Seller.

1.3.   "Product", for purposes of this Supply Agreement only, means either the
       Active Ingredient or any pharmaceutical preparation containing the Active
       Ingredient (sometimes hereinafter referred to as bulk labelled
       lyophilized vials), and including future formulation changes developed
       during the term of this Supply Agreement that are used by Seller to
       supply Buyer.

                                       1
<PAGE>
 
1.4.   "Specifications" has the meaning ascribed to such term in Section 5.1.1.

1.5.   "Territory" means the United States and Canada and respective possessions
       or territories.

1.6.   Other Terms.  The defined terms used herein and not defined above shall
       have the respective meanings assigned to such terms in the Asset Purchase
       Agreement.


2.     SUBJECT MATTER

2.1.   Subject Matter.  Subject to the terms and conditions of this Agreement,
       Seller or its designated Affiliate(s) shall supply to Buyer during the
       term of the present Agreement Buyer's requirements of the bulk labelled
       lyophilized vials or bulk Active Ingredient manufactured by Seller or
       Affiliates of Seller, provided that Seller and its Affiliates shall not
       be obliged to supply bulk labelled lyophilized vials or bulk Active
       Ingredient in excess of its capacity.


3.     FORECASTS AND ORDERS

3.1.   Forecasts.  Buyer shall give Seller or Seller's designated Affiliate(s)
       within one month from the date of this Agreement and thereafter at the
       beginning of every calendar quarter the estimate by month of its
       requirements of bulk labelled lyophilized vials or bulk Active Ingredient
       for the following 12 (twelve) months. The first 3 (three) months of each
       estimate shall constitute a firm order. Each successive estimate (after
       the first such estimate) shall update the estimate previously given for
       the last calendar quarter covered by the immediately preceding estimate
       and add an estimate for the calendar quarter following immediately
       thereafter, such that Seller shall have sufficient information upon which
       to schedule its manufacturing operations so as to be able to meet Buyer's
       estimated requirements of the bulk labelled lyophilized vials or bulk
       Active Ingredient. Seller shall not provide any of the forecast
       information set forth above to Genentech, Inc.

3.2.   Orders.  Buyer shall provide a written firm purchase order to Seller or
       its designated Affiliate(s) (at one of Seller's or its Affiliates'
       offices designated by Seller) at least 3 (three) months prior to a
       requested delivery date. Seller or its designated Affiliate(s) shall
       supply the bulk labelled lyophilized vials or bulk Active Ingredient
       within 3 (three) months after receipt of a firm order therefor from
       Buyer. In the event that the sum of the orders for delivery within any

                                       2
<PAGE>

THE REGISTRANT HAS REQUESTED CONFIDENTIAL TREATMENT FOR CERTAIN PORTIONS OF THIS
AGREEMENT. THOSE PORTIONS HAVE BEEN OMITTED FROM THIS COPY OF THE AGREEMENT AT 
THE PLACES INDICATED BY ASTERICKS (*); AND HAVE BEEN FILED SEPARATELY WITH THE 
SECURITIES AND EXCHANGE COMMISSION

       calendar quarter exceeds 100% (one hundred percent) of the most recent
       estimate given by Buyer for such calendar trimester pursuant to Section
       3.1 above, and subject to the supply obligation set forth in Section 2.1
       above, Seller and Buyer shall consult with each other and Seller shall be
       allowed such reasonable time as is needed to arrange for the orderly
       manufacture of such additional requirements.

3.3    Minimum Order Size.  The minimum size of any order for any bulk labelled
       lyophilized vials or bulk Active Ingredient shall be one full batch of
       such bulk labelled lyophilized vials (as set forth in Schedule 3.3
       hereto) or bulk Active Ingredient with larger orders being in whole
       number multiples of such a batch.


4.     PRICE, DELIVERY AND PAYMENT CONDITIONS

4.1    Price.  Buyer shall purchase the bulk labelled lyophilized vials from the
       Seller at DM [*] per vial or DM [*] per amount of bulk Active
       Ingredient contained in one such vial or, in the case of formulation
       changes, a price to be agreed on by the parties in good faith.

4.2    Delivery Conditions. Title and risk of loss or damage to any bulk
       labelled lyophilized vials or bulk Active Ingredient supplied hereunder
       shall pass to Buyer upon delivery at Seller's or its Affiliate's
       manufacturing plant to a common carrier for delivery of such Product.
       Buyer shall be responsible and pay for any and all customs duties, value
       added, excise and other taxes, clearances and/or levies of any type
       whatsoever with regard to the supply of the Product from Seller or its
       Affiliate hereunder Seller may select a common carrier for shipment of
       goods; delivery will be per Buyer's instruction.

4.3    Certificate of Analysis.  All bulk labelled lyophilized vials or bulk
       Active Ingredient supplied to Buyer shall be accompanied by a signed and
       dated Certificate of Analysis, which shall be substantially in the form
       attached as Schedule 4.3 hereto. A copy of this Certificate of Analysis
       will be sent by fax to the appropriate contact person at Buyer. The
       original Certificate of Analysis shall be dispatched by airmail, or sent
       together with the Product, at the time of shipment in accordance with
       Buyer's instructions.

4.4    Invoicing and Payment Conditions.  Seller or its designated Affiliate(s)
       shall invoice Buyer in German marks for all supplies of bulk labelled
       lyophilized vials or bulk Active Ingredient hereunder monthly after
       delivery as defined herein. Buyer shall effect payment of such invoices
       in German marks to Seller's or its Affiliate(s) designated bank account
       within 30 (thirty) days after the date of 

                                       3

                       Confidential Treatment Requested
<PAGE>
 
       invoice. Seller and its Affiliate(s) may charge a late payment fee of
       1.5% of the outstanding balance for each 30 (thirty) day period
       thereafter during which said balance remains unpaid.

4.5    Supply. If there is an interruption in the manufacture of the bulk
       labelled lyophilized vials or bulk Active Ingredient for a period of more
       than 45 days (i) caused by the actions of Seller or its Affiliates, Buyer
       shall have first call on the then available supply, or (ii) caused by
       actions other than those of Seller or its Affiliates, the then available
       supply shall be divided between Seller and Buyer based upon their
       respective previous three months' sale.

5.     SPECIFICATIONS, WARRANTY AND INDEMNIFICATION

5.1    Warranties; Specifications and Analysis

5.1.1. Seller represents and warrants that the bulk labelled lyophilized vials
       or bulk Active Ingredient manufactured by Seller or its Affiliate(s) for
       Buyer pursuant meet the FDA approved specifications therefor, as may be
       amended from time to time by Seller after reasonable prior notice to
       Buyer which is sufficient to enable Buyer to assess the impact of the
       amendment on Buyer's manufacturing process, but not exceeding 60 (sixty)
       days, and prior approval by the respective registration authorities, if
       required (the "Specifications").

       Seller or its Affiliate shall send to Buyer with each such shipment a
       certificate of analysis specifying, inter alia, the results of each of
       the determinations required to show conformance of such shipment with the
       Specifications. The figures set forth in the certificate of analysis
       shall be accepted as accurate for the purposes of this Agreement unless
       Buyer within 30 (thirty) days of the receipt of such shipment notifies
       Seller in writing that it has analysed such shipment in accordance with
       Seller's or its Affiliates' methods of analysis, as may be amended from
       time to time by Seller after reasonable prior notice to Buyer which is
       sufficient to enable Buyer to assess the impact of the amendment on
       Buyer's manufacturing process, but not exceeding 60 (sixty) days, and
       prior approval by the respective registration authorities, if required
       and has determined that such shipment does not conform to the
       Specifications. In the latter event, Buyer and Seller agree to consult
       with each other in order to resolve the discrepancy between each other's
       determinations. If such consultations do not resolve the discrepancy,
       Buyer and Seller agree to nominate an independent, reputable laboratory,
       acceptable to both parties, which shall carry out determinations on
       representative samples taken from such shipment, using Seller's or its
       Affiliates' methods of analysis, and the resulting determinations shall
       be binding on Buyer and Seller for the purposes hereof. The 

                                       4
<PAGE>
 
       cost of the analysis of such independent laboratory shall be borne by the
       party whose testing was in error.

5.1.2. If it is determined that a shipment of bulk labelled lyophilized vials or
       bulk Active Ingredient, as of the date shipped, does not conform to the
       Specifications, Seller shall replace such shipment with a substitute
       shipment that meets the Specifications. The above shall be Seller's and
       its Affiliates' sole liability for, and Buyer's sole and exclusive remedy
       for the supply of any Product that do not conform to the Specifications.
       The non-conforming shipment shall be returned, at Seller's expense by
       Buyer to Seller upon final determination in accordance with Section 5.1.1
       above that it does not meet the Specifications.

5.2    DISCLAIMER. EXCEPT AS SET FORTH IN SECTIONS 5.1.1 AND 5.1.2 ABOVE, SELLER
       MAKES NO REPRESENTATIONS AND DISCLAIMS ANY WARRANTIES OF ANY KIND,
       EXPRESS OR IMPLIED, TO BUYER FOR ANY BULK LABELLED LYOPHILIZED VIALS OR
       BULK ACTIVE INGREDIENT SUPPLIED BY SELLER OR ITS AFFILIATES HEREUNDER,
       INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY OR FITNESS
       FOR A PARTICULAR PURPOSE.

5.3    Recall. Buyer is competent and responsible for deciding about and
       effecting a recall of the Product. In case of such a recall, to the
       extent necessary or needed, Seller shall cooperate with Buyer as
       reasonably required in carrying out any such recall. Buyer shall
       reimburse Seller and its Affiliates for any cost reasonably expended by
       Seller and its Affiliates to effect the recall, provided that if a recall
       is caused by non-compliance of the Product with the Specifications at the
       date of shipment, Seller shall reimburse Buyer for (a) any cost
       reasonably expended by Buyer to effect the recall, (b) any manufacturing
       and shipping fees paid to Seller by Buyer for recalled Product, and (c)
       any reasonable disposal costs for such recalled Product.

5.4    Indemnification

5.4.1. Indemnification by Seller. Subject to the following limitations, Seller
       shall be liable for and shall indemnify and hold harmless Buyer in
       respect of any and all liabilities, losses, damages, claims or lawsuits,
       including but not limited to any liabilities, losses, damages, claims or
       lawsuits arising out of the manufacture, use, sale or marketing of the
       Product, including but not limited to any claims made (directly or
       indirectly) by or on behalf of consumers who have purchased or otherwise
       obtained and/or used the Product, arising from Seller's (i) failure to

                                       5
<PAGE>
 
       supply bulk labelled lyophilized vials or bulk Active Ingredient meeting
       FDA specifications upon delivery to Buyer, provided that Buyer gives
       Seller prompt, adequate notice of such third party claim and permits
       Seller to assume the sole control of all phases of the defense and/or
       settlement of such claim, including the selection of counsel, it being
       understood that Seller shall not be liable for any negligent act or
       omission of Buyer or for any representations and warranties, express or
       implied, made by Buyer that exceed the representations and warranties
       made by Seller to Buyer under this Agreement, (ii) breach of this
       Agreement, (iii) negligence or wilful misconduct, (iv) breach of
       statutory duty, or (v) act, omission or default howsoever caused on the
       part of Seller, its Affiliates, employees and agents. The indemnity by
       Seller set forth in clause (i) above shall include loss of Buyer's
       profits unless Seller is able to demonstrate that Seller's failure to
       supply bulk labelled lyophilized vials or bulk Active Ingredient meeting
       FDA specifications upon delivery to Buyer was entirely beyond Seller's
       control and in no part the result of negligence or wilful misconduct on
       the part of Seller.

5.4.2. Indemnification by Buyer. Subject to the following limitations, Buyer
       shall be liable for and shall indemnify and hold harmless Seller in
       respect of any and all liabilities, losses, damages, claims or lawsuits,
       including but not limited to any liabilities, losses, damages, claims or
       lawsuits arising out of the manufacture, use, sale or marketing of the
       Product, including but not limited to any claims made (directly or
       indirectly) by or on behalf of consumers who have purchased or otherwise
       obtained and/or used the Product, arising from Buyer's (i) breach of this
       Agreement, (ii) negligence or wilful misconduct, (iii) breach of
       statutory duty or (iv) act, omission or default howsoever caused on the
       party of Buyer, its employees and agents. Notwithstanding the foregoing,
       Buyer shall not be liable to Seller, whether in contract, tort or
       otherwise, for any consequential, indirect, economic or financial loss or
       damage (including, without prejudice to the generality of the foregoing,
       any loss of turnover, revenue, profits, business or goodwill) howsoever
       caused.


6.     CONFIDENTIALITY

6.1    Subject to the Asset Purchase Agreement, each party shall during and for
       5 (five) years after the term of this Agreement not use for any other
       purpose than contemplated under this Agreement and not disclose to any
       person (not including a contract manufacturer of Buyer with respect to
       manufacture of the Active Ingredient, provided that such contract
       manufacturer (i) shall be obligated to keep such confidential information
       confidential and (ii) shall not use such information for any purpose
       other than with respect to manufacture of the Active Ingredient) 

                                       6
<PAGE>
 
     any confidential information received from the other party concerning
     formulas, manufacturing processes, commercial methods and other activities
     of the other party, except to the extent required by government authorities
     for the execution of this Agreement or relating to the safety of the
     Product.

6.2  It is understood that confidential information shall not include
     information which the party receiving the information (in the case of
     either Seller or Buyer, their Affiliates and their respective
     representatives, "Receiving Party") can prove (a) was in the public domain
     prior to the date of this agreement or thereafter enters the public domain
     through no fault of Receiving Party; (b) was available to Receiving Party
     on a non-confidential basis prior to its disclosure to Receiving Party by
     the party providing the information (in the case of either Seller or Buyer,
     their Affiliates and their respective representatives, "Providing Party");
     (c) is later lawfully acquired by Receiving Party from sources other than
     Providing Party who are not, to the best of knowledge of Receiving Party
     subject to any legally binding obligation to keep such information
     confidential; (d) independently developed by Receiving Party without
     reference to such confidential information; or (e) is required by law,
     regulation, rule, act or order of any governmental authority or agency to
     be disclosed by Receiving Party; provided, however, that in the case of
     (e), Receiving Party gives Providing Party sufficient advance written
     notice to permit Providing Party to seek a protective order with respect to
     such information and thereafter Receiving Party discloses only the minimum
     information required to be disclosed in order to comply.


7.   TERM AND TERMINATION

7.1  Term.  The present Agreement shall become effective at the Closing Date and
     shall remain in force for a period which is the earlier of (i) four years
     and (ii) three months following the date Buyer obtains all necessary
     approvals to manufacture the Active Ingredient, subject to extension with
     approval of the FTC.

7.2  Termination.  Notwithstanding Section 7.1 above, either party may terminate
     this Agreement at any time with immediate effect by written notice to the
     other party.

     a)   if the other party has failed to perform any of its obligations
          hereunder and has not corrected such default within 60 (sixty) days
          after dispute resolution pursuant to Section 8.1 hereof (provided
          that, even following the 60-day period referred to above, the Seller
          shall not have a right to terminate pursuant to this Section 7.2 a) as
          long as Buyer continues to pay all amounts due to Seller in accordance
          with Sections 4.4. and 5.4.2 

                                       7
<PAGE>
 
          hereof);

     b)   if the other party is or will inevitably in the near future be
          dissolved, liquidated or bankrupt; provided that Seller shall not have
          a right to terminate pursuant to this Section 7.2 b) as long as Buyer
          continues to pay all amounts due to Seller in accordance with Section
          4.4.


8.   ARBITRATION AND GOVERNING LAW

8.1  Arbitration.  Except for the right of either party to apply to a court of
     competent jurisdiction for a temporary restraining order to preserve the
     status quo or prevent irreparable harm pending the selection and
     confirmation of a panel of arbitrators, any dispute, controversy, or claims
     arising under, out of or relating to this Agreement (and subsequent
     amendments thereof), its valid conclusion, binding effect, interpretation,
     performance, breach or termination, including tort claims, shall be
     referred to and finally determined by arbitration, to the exclusion of any
     courts of law, in accordance with the Rules of Arbitration of the
     International Chamber of Commerce as in force at the time when initiating
     the arbitration. The arbitral tribunal shall consist of three arbitrators.
     The place of arbitration shall be Hamilton, Bermuda. The language to be
     used in the arbitral proceedings shall be English. The arbitration decision
     shall be final and binding upon the parties and the parties agree that any
     award granted pursuant to such decision may be entered forthwith in any
     court of competent jurisdiction. This arbitration clause and any award
     rendered pursuant to it shall be governed by the United Nations Convention
     on the Recognition and Enforcement of Foreign Arbitration Awards signed in
     New York as of 10 June, 1958. The party to whom a favourable ruling is
     awarded shall be entitled to reimbursement of all its reasonable costs and
     expenses in arbitration by the other party.

8.2  Governing Law.  The present Agreement shall be subject to the substantive
     law of Bermuda (regardless of its or any other jurisdiction's choice of law
     principles).


9.   MISCELLANEOUS

9.1  Force Majeure.  If any of the parties hereto finds itself in spite of
     ordinary care unable by reason of a duly evidenced case of force majeure,
     i.e. an event beyond its control, to carry out its obligations hereunder in
     whole or in part, the obligations of such party, to the extent that they
     are affected by such force majeure, shall be suspended as long as the
     impossibility so caused shall endure. 

                                       8
<PAGE>
 
     The party affected by force majeure shall immediately inform the other
     party and shall make all reasonable efforts to remedy the situation created
     by such force majeure as soon as possible.

9.2  Independent Contractor.  Each party shall act solely as an independent
     contractor and nothing in this Agreement shall be construed to give either
     the power or authority to enter into or incur, any commitments, expenses or
     liabilities whatsoever on behalf of the other party.  Nothing herein shall
     be construed to create the relationship of partnership, principal and
     agent, or joint venture between Seller and Buyer.

9.3  Quality Control.  In connection with the obligations of Seller and Buyer as
     set forth in this Agreement, Seller and Buyer shall review the quality
     control procedures required by the FDA and the Department of Health Canada
     in order to determine the most practical way in which to comply with such
     procedures.

9.4  Notices.  Any notice required or permitted to be given hereunder shall be
     deemed sufficient if sent by facsimile letter or overnight courier, or
     delivered by hand to Seller or Buyer at the respective addresses and
     facsimile numbers set forth below or at such other address and facsimile
     number as either party hereto may designate. If sent by facsimile letter,
     notice shall be deemed given when the transmission is completed if the
     sender has a confirmed transmission report and if the sender has sent a
     confirmation copy by registered mail. If a confirmed transmission report
     does not exist, then the notice will be deemed given when the notice is
     actually received by the person to whom it is sent. If delivered by
     overnight courier, notice shall be deemed given when it has been signed
     for. If delivered by hand, notice shall be deemed given when received.

     if to Buyer, to:

     Centocor, Inc.
     200 Great Valley Parkway
     Malvern, PA 19355-1307
     Attention: Corporate Secretary
     Fax: 610-651-6331


     if to Seller, to:
     Boehringer Mannheim GmbH
     Sandhofer Str. 116
     D-68305 Mannheim

                                       9
<PAGE>
 
     Germany
     Attention: Claus-Jorg Rutsch
     Fax: ++49 621 759 3523

     with a copy to:

     F.Hoffmann-La Roche Ltd
     CH-4070 Basel, Switzerland
     Attention: Corporate Law Department
     Fax: ++41 61 688 1396

9.5  Assignment.  Neither party shall have the right to assign the present
     Agreement or any part thereof to any third party without the prior written
     approval of the other party.  However, all Affiliates of Seller shall not
     be deemed to be third parties within the meaning of this provision.

9.6  Amendments: No Waiver.  No provision of this Agreement may be amended,
     revoked or waived except by a writing signed and delivered by an authorized
     officer of each party.  No failure or delay on the part or either party in
     exercising any right hereunder will operate as a waiver of, or impair, any
     such right.  No single or partial exercise of any such right will preclude
     any other or further exercise thereof or the exercise of any other right.
     No waiver of any such right will be deemed a waiver of any other right
     hereunder.

9.7  Validity.  Should any part or provision of this Agreement be held
     unenforceable or invalid, the invalid or unenforceable provision shall be
     replaced with a provision that accomplishes, to the maximum possible
     extent, the original business purpose of such provision in a valid and
     enforceable manner, and the remainder of this Agreement shall remain
     binding upon the parties.

9.8  Counterparts.  This Agreement may be executed in one or more counterparts
     all of which shall together constitute one and the same instrument and
     shall become effective when a counterpart has been signed by Buyer and
     delivered to Seller and a counterpart has been signed by Seller and
     delivered to Buyer.

                                       10
<PAGE>
 
     IN WITNESS WHEREOF, this Agreement has been signed by duly authorized
representatives of each of the parties hereto as of the date first above
written.


Boehringer Mannheim GmbH            Centocor, Inc.



By:                                 By: 
    -------------------------           --------------------------
Name:                               Name:
     ------------------------            ------------------------- 
Title:                              Title:
      -----------------------             ------------------------        

                                       11
<PAGE>

THE REGISTRANT HAS REQUESTED CONFIDENTIAL TREATMENT FOR CERTAIN PORTIONS OF THIS
AGREEMENT. THOSE PORTIONS HAVE BEEN OMITTED FROM THIS COPY OF THE AGREEMENT AT 
THE PLACES INDICATED BY ASTERICKS (*); AND HAVE BEEN FILED SEPARATELY WITH THE 
SECURITIES AND EXCHANGE COMMISSION
 
                                                                    SCHEDULE 3.3


For bulk labelled vials: One full batch equals [*]


For bulk Active Ingredient:  One full batch equals 100g (one hundred grams).

                                       12
<PAGE>
 

                                                                       Exhibit D
                                                                       ---------

                               KEEP WELL AGREEMENT



     Agreement dated as of            , 1998  between Roche Holding Ltd (the
"Parent") and Roche Healthcare Limited (the "Subsidiary").

     WHEREAS the Parent owns directly or indirectly all the capital stock of the
Subsidiary; and

     WHEREAS the Subsidiary proposes to enter into an Asset Purchase Agreement
with Centocor, Inc. (the "Asset Purchase Agreement").

     NOW, THEREFORE, the parties agree as follows:

     1.   Stock Ownership of the Subsidiary. At all times during the term of
          ---------------------------------                                 
this Agreement, the Parent shall directly or indirectly own and hold the entire
legal title to and beneficial interest in all the outstanding shares of stock of
the Subsidiary having the right to vote for the election of members of the Board
of Directors of the Subsidiary and will not directly or indirectly pledge or in
any way encumber or otherwise dispose of any such shares of stock, unless
required to dispose of any or all such shares of stock pursuant to a court
decree or order of any governmental authority which, in the opinion of counsel
to the Parent, may not be successfully challenged.

     2.   Maintenance of Consolidated Net Worth. The Parent agrees that it shall
          -------------------------------------                                 
cause the Subsidiary to have a Consolidated Net Worth of at least U.S.$1,000,000
at all times.

     For purposes of this Agreement, the term "Consolidated Net Worth" shall
mean the excess of total assets of the Subsidiary and its consolidated
subsidiaries over total liabilities of the Subsidiary and its consolidated
subsidiaries, total assets and total liabilities each to be determined in
accordance with generally accepted international accounting principles
consistently applied.

     3.   Waiver. The Parent hereby waives any failure or delay on the part of
          ------                                                              
the Subsidiary in asserting or enforcing any of its rights or in making any
claims or demands hereunder.

     4.   Not a Guarantee. This Agreement is not, and nothing herein contained
          ---------------                                                     
and nothing done pursuant hereto by the Parent shall be deemed to 
<PAGE>
 
constitute, a guarantee by the Parent of the payment of any obligation,
indebtedness or liability, of any kind or character whatsoever, of the
Subsidiary. The only parties to this Agreement are the Subsidiary and the
Parent, and this Agreement shall not confer upon any other person any right or
claim against the Parent.

     5.   Modification, Amendment or Termination. This agreement may be
          --------------------------------------                       
modified, amended or terminated by the written agreement of the parties;
provided, however, that no such modification, amendment or termination shall
have any adverse effect upon the ability of the Subsidiary to meet its
obligations under Section 3.4 and Section 13.7 of the Asset Purchase Agreement
without the written consent of Centocor, Inc.

     6.   Bankruptcy, Liquidation or Moratorium. Any rights and obligations
          -------------------------------------                            
which either of the parties has under this Agreement will remain valid and
binding notwithstanding any bankruptcy or liquidation of, or moratorium
involving, the Subsidiary.

     7.   Rights of the Subsidiary. It is the intention of the parties in
          ------------------------                                       
entering into this Agreement to benefit the Subsidiary, and accordingly the
obligations of the Parent under this Agreement may be enforced exclusively by
the Subsidiary at any time against the Parent.

     8.   Successors. The agreements herein set forth shall be mutually binding
          ----------                                                           
upon, and inure to the mutual benefit of, the Parent and the Subsidiary and
their respective successors.

     9.   Governing Law. This Agreement shall be governed by the laws of Bermuda
          -------------                                                         
(regardless of its or any other jurisdiction's choice of law principles).

                                       2
<PAGE>
 
     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be 
executed and delivered by their respective officers thereunto duly authorized as
of the day and year first above written.



Roche Holding Ltd                   Roche Healthcare Limited


By:                                 By:
   --------------------------          ---------------------------



By:
   --------------------------

                                       3