EXTENSION OF PROMISSORY NOTE

This Extension of Promissory Note (the "Extension")  is made  effective as of
December 7, 1996 (the "Effective Date"), by and between Corvas International,
Inc., a Delaware corporation ("Lender"), and Randall E. Woods ("Borrower") with
respect to the following:

    A.   Borrower executed a Promissory Note for a principal amount of
$200,000.00, dated June 25, 1996 (the "Note") secured by that certain Deed of
Trust dated as of June 25, 1996, encumbering Borrower's real property in
Potomac, Maryland (the "Property");  and

    B.   The outstanding principal  amount of the Note was due and payable on
the earlier of December 7, 1996, or the closing of the sale of the Property or
any transfer by Borrower of the interest therein; and

    C.   Borrower has made all reasonable efforts to sell the Property and has
been unable to do so.

    The parties hereto agree as follows:

    As approved by resolution of the Board of Directors of Lender at its Board
meeting held December 4, 1996, Lender and Borrower have agreed to extend the
term of the Note for a period of one (1) year, expiring on the sale of the
Maryland residence or December 7, 1997, whichever shall first occur.  

    Except as set forth herein, all of the remaining terms, conditions and
provisions of the Note shall remain in full force and effect.

IN WITNESS WHEREOF, the parties have executed this Extension effective as of the
Effective Date.

AGREED TO AND ACCEPTED:

"LENDER"                                    "BORROWER"

CORVAS INTERNATIONAL, INC.

By: /s/ JOHN E. CRAWFORD                    By: /s/ RANDALL E. WOODS 
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    John E. Crawford, Executive Vice             Randall E. Woods
    President, Chief Financial Officer and
    Corporate Secretary

Dated: January  30, 1997                    Dated:  January  29, 1997     
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