<PAGE>

EXHIBIT 10.54

                            BUY OUT AGREEMENT

        This Buy Out Agreement (the "AGREEMENT") is made as of the ninth day 
of September, 1996, between Cortech, Inc., a Delaware corporation having its 
principal place of business at 6850 North Broadway, Denver, Colorado 80221 
("CORTECH") and Hoechst Marion Roussel, Inc., a Delaware corporation having 
its principal place of business at 9300 Ward Parkway, Kansas City, Missouri 
64114 ("HMRI"), as successor in interest to Marion Laboratories, Inc.

        WHEREAS, Cortech and HMRI are parties to the Stock Purchase Agreement 
dated as of February 29, 1988 (the "PURCHASE AGREEMENT");

        WHEREAS, pursuant to Sections 6.03 and 6.04 of the Purchase Agreement 
Cortech granted HMRI a right of first offer with respect to certain rights to 
new products, technologies and therapeutic applications which may result from 
Cortech's research and development activities (the "RIGHT OF FIRST OFFER"); 

        WHEREAS, Cortech and HMRI desire to terminate the Right of First 
Offer and to finally and fully compromise, settle and discharge all claims, 
controversies, demands, actions or causes of action which HMRI may have or 
claim to have arising out of or in connection with the Right of First Offer.

                                AGREEMENT

        NOW, THEREFORE, IN CONSIDERATION of the promises and mutual covenants 
and agreements herein contained, the parties hereto covenant and agree as 
follows:

1.      TERMINATION OF RIGHT OF FIRST OFFER.  The parties agree that Sections 
        6.03 and 6.04 of the Purchase Agreement are hereby terminated.  All 
        other provisions of the Purchase Agreement shall remain in full force 
        and effect.

2.      RELEASE. HMRI hereby forever generally and completely 
        releases and discharges Cortech and its servants, agents, directors, 
        officers and employees, of and from any and all claims and demands of 
        every kind and nature, in law, equity or otherwise, known and 
        unknown, arising out of or in connection with their respective 
        obligations, activities and/or dealings under the Right of First 
        Offer at any time prior to the date of this Agreement.

3.      CONSIDERATION.  As consideration for this Agreement, Cortech hereby 
        agrees to issue to HMRI 200,000 shares of Cortech Common Stock par 
        value $.002 per share (the "Shares"). Except as set forth in the next 
        sentence, HMRI shall have piggyback registration rights with respect 
        to the Shares on the terms and subject to the conditions set forth in 
        Section 7.09 of the Purchase Agreement.  In the event of a 
        registration pursuant to subsection (a) thereof in which an 
        underwriter has determined that inclusion of all shares requested to 
        be sold by selling security holders would have a material adverse 
        effect on the offering, the Shares will rank junior in priority to 
        all shares of Cortech securities for which registration rights have 
        been granted prior hereto.


                                     1.

<PAGE>

4.      ACKNOWLEDGMENT.  HMRI acknowledges that it has had access, under 
        confidentiality, to all material information concerning New Product 
        Opportunities (as defined in the Purchase Agreement) subject to the 
        Right of First Offer which it has requested, as well as all current 
        public information concerning Cortech.  HMRI also acknowledges that 
        it has had the opportunity to, and has to its satisfaction, 
        questioned and otherwise consulted the officers of Cortech with 
        respect to the prospects of the New Product Opportunities, and the 
        value of the Shares.  HMRI further acknowledges that the Shares are 
        being acquired by HMRI for its own account, for investment and not 
        with a view to resale, and that such Shares have not been registered 
        under the Securities Act of 1933, as amended, and may not be resold 
        unless registered under such Act or pursuant to an exemption from 
        such registration.  

5.      MISCELLANEOUS.  

        a)      ENTIRE AGREEMENT.  This Agreement and the exhibits attached 
                hereto contain the entire agreement between the parties 
                hereto and constitute the complete, final and exclusive 
                embodiment of their agreement with respect to the subject 
                matter hereof. The terms of this Agreement are contractual 
                and not a mere recital.  This Agreement is executed without 
                reliance upon any promise, warranty or representation by any 
                party or any representative of any party other than those 
                expressly contained herein, and each party has carefully read 
                this Agreement, has been advised of its meaning and 
                consequences by his or its respective attorney, and signs the 
                same of its own free will.

        b)      ASSIGNMENT.  Any unauthorized assignment of this Agreement is 
                void.  This Agreement shall bind the heirs, personal 
                representatives, successors and assigns of each party, and 
                inure to the benefit of each party, its agents, directors, 
                officers, employees, servants, successors and assigns.

        c)      EXPENSES.  Each party to this Agreement will bear its own costs,
                expenses, and attorney's fees, whether taxable or otherwise, 
                incurred in or arising out of or in any way related to the 
                matters released herein.

        d)      CHOICE OF LAW.  This Agreement shall be deemed to have been 
                entered into and shall be construed and enforced in 
                accordance with the laws of the State of Colorado as applied 
                to contracts made and to be performed entirely within 
                Colorado.

        e)      COUNTERPARTS.  This Agreement may be executed in counterparts,
                each of which shall be deemed an original, but all of which 
                together shall constitute one and the same instrument.

        IN WITNESS WHEREOF, the parties have duly authorized and caused this 
Agreement to be executed on the date first above written.

CORTECH, INC.                          HOECHST MARION ROUSSEL, INC.


By:   /s/ KENNETH LYNN                 By:  /s/ FRANK L. DOUGLAS, M.D. 
   ----------------------------           -------------------------------
Title:  President and CEO              Title:  Executive Vice President
      -------------------------              ----------------------------

                                     2.