Document:

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                                                                   EXHIBIT 10.52

                             SECOND AMENDMENT TO THE
                           CORVAS INTERNATIONAL, INC.
                    401(K) COMPENSATION DEFERRAL SAVINGS PLAN
                               AND TRUST AGREEMENT

     The Corvas International, Inc. 401(k) Compensation Deferral Savings Plan
and Trust Agreement (the "Plan"), as amended and restated effective January 1,
1997, is hereby amended effective as of the dates shown herein, in the manner
set forth below:

     I. The amendment set forth below is adopted as of the dates set forth
herein to enable the Plan to comply with the Economic Growth and Tax Relief
Reconciliation Act of 2001 ("EGTRRA"):

     SECTION 1. GENERAL PROVISIONS

     1. ADOPTION AND EFFECTIVE DATE OF AMENDMENT. This Amendment of the Plan is
     adopted to reflect certain provisions of the Economic Growth and Tax Relief
     Reconciliation Act of 2001 ("EGTRRA"). This Amendment is intended as good
     faith compliance with the requirements of EGTRRA and is to be construed in
     accordance with EGTRRA and guidance issued thereunder. Except as otherwise
     provided, this Amendment shall be effective as of the first day of the
     first Plan Year beginning after December 31, 2001.

     2. SUPERSESSION OF INCONSISTENT PROVISIONS. This Amendment shall supersede
     the provisions of the Plan to the extent those provisions are inconsistent
     with the provisions of this Amendment.

     SECTION 2. PLAN LOANS FOR OWNER-EMPLOYEES AND SHAREHOLDER EMPLOYEES

     Effective for Plan loans made after December 31, 2001, Plan provisions
     prohibiting loans to any owner-employee or shareholder-employee shall cease
     to apply.

     SECTION 3. LIMITATIONS ON CONTRIBUTIONS

     1. EFFECTIVE DATE. This Section shall be effective for Limitation Years
     beginning after December 31, 2001.

     2. MAXIMUM ANNUAL ADDITION. Except to the extent permitted under Section 10
     of this Amendment and Section 414(v) of the Code, if applicable, the annual
     addition that may be contributed or allocated to a Participant's Account
     under the Plan for any Limitation Year shall not exceed the lesser of:

     (a) $40,000, as adjusted for increases in the cost-of-living under Section
     415(d) of the Code, or

     (b) 100 percent of the Participant's Compensation, within the meaning of
     Section 415(c)(3) of the Code, for the Limitation Year.

     The Compensation limit referred to in (b) shall not apply to any
     contribution for medical benefits after separation from service (within the
     meaning of Section 401(h) or Section 419A(f)(2) of the Code) which is
     otherwise treated as an annual addition.

                                       1.
<PAGE>

     SECTION 4. INCREASE IN COMPENSATION LIMIT

     The annual Compensation of each Participant taken into account in
     determining allocations for any Plan Year beginning after December 31,
     2001, shall not exceed $200,000, as adjusted for cost-of-living increases
     in accordance with Section 401(a)(17)(B) of the Code. Annual Compensation
     means Compensation during the Plan Year or such other consecutive 12-month
     period over which Compensation is otherwise determined under the Plan (the
     determination period). The cost-of-living adjustment in effect for a
     calendar year applies to annual Compensation for the determination period
     that begins with or within such calendar year.

     SECTION 5. MODIFICATION OF TOP-HEAVY RULES

     1. EFFECTIVE DATE. This Section shall apply for purposes of determining
     whether the Plan is a top-heavy plan under Section 416(g) of the Code for
     Plan Years beginning after December 31, 2001, and whether the Plan
     satisfies the minimum benefits requirements of Section 416(c) of the Code
     for such years. This Section amends Article 15 of the Plan.

     2. DETERMINATION OF TOP-HEAVY STATUS.

     (a) KEY EMPLOYEE. Key Employee means any Employee or former Employee
     (including any deceased Employee) who at any time during the Plan Year that
     includes the determination date was an officer of the Employer having
     annual Compensation greater than $130,000 (as adjusted under Section
     416(i)(1) of the Code for Plan Years beginning after December 31, 2002), a
     5-percent owner of the Employer, or a 1-percent owner of the Employer
     having annual Compensation of more than $150,000. For this purpose, annual
     Compensation means Compensation within the meaning of Section 415(c)(3) of
     the Code. The determination of who is a Key Employee will be made in
     accordance with Section 416(i)(1) of the Code and the applicable
     regulations and other guidance of general applicability issued thereunder.

     (b) DETERMINATION OF PRESENT VALUES AND AMOUNTS. This Section shall apply
     for purposes of determining the present values of accrued benefits and the
     amounts of account balances of Employees as of the determination date.

     (c) DISTRIBUTIONS DURING YEAR ENDING ON THE DETERMINATION DATE. The present
     values of accrued benefits and the amounts of account balances of an
     Employee as of the determination date shall be increased by the
     distributions made with respect to the Employee under the Plan and any plan
     aggregated with the Plan under Section 416(g)(2) of the Code during the
     1-year period ending on the determination date. The preceding sentence also
     shall apply to distributions under a terminated plan which, had it not been
     terminated, would have been aggregated with the Plan under Section
     416(g)(2)(A)(i) of the Code. In the case of a distribution made for a
     reason other than separation from service, death, or disability, this
     provision shall be applied by substituting "5-year period" for "1-year
     period."

     (d) EMPLOYEES NOT PERFORMING SERVICES DURING YEAR ENDING ON THE
     DETERMINATION DATE. The accrued benefits and accounts of any individual who
     has not performed services for the Employer during the 1-year period ending
     on the determination date shall not be taken into account.

                                       2.
<PAGE>

     3. MINIMUM BENEFITS. Employer matching contributions shall be taken into
     account for purposes of satisfying the minimum contribution requirements of
     Section 416(c)(2) of the Code and the Plan. The preceding sentence shall
     apply with respect to matching contributions under the Plan or, if the Plan
     provides that the minimum contribution requirement shall be met in another
     plan, such other plan. Employer matching contributions that are used to
     satisfy the minimum contribution requirements shall be treated as matching
     contributions for purposes of the Actual Contribution Percentage test and
     other requirements of Section 401(m) of the Code.

     SECTION 6. DIRECT ROLLOVERS OF PLAN DISTRIBUTIONS

     1. EFFECTIVE DATE. This Section shall apply to distributions made after
     December 31, 2001.

     2. MODIFICATION OF DEFINITION OF ELIGIBLE RETIREMENT PLAN. For purposes of
     the direct rollover provisions in Section 4.6 of the Plan, an Eligible
     Retirement Plan also shall mean an annuity contract described in Section
     403(b) of the Code and an eligible plan under Section 457(b) of the Code
     which is maintained by a state, political subdivision of a state, or any
     agency or instrumentality of a state or political subdivision of a state
     and which agrees to separately account for amounts transferred into such
     plan from this Plan. The definition of Eligible Retirement Plan also shall
     apply in the case of a distribution to a surviving spouse, or to a spouse
     or former spouse who is the alternate payee under a qualified domestic
     relation order, as defined in Section 414(p) of the Code.

     3. MODIFICATION OF DEFINITION OF ELIGIBLE ROLLOVER DISTRIBUTION TO EXCLUDE
     HARDSHIP DISTRIBUTIONS. For purposes of the direct rollover provisions in
     Section 4.6 of the Plan, any amount that is distributed on account of
     Hardship shall not be an Eligible Rollover Distribution and the Distributee
     may not elect to have any portion of such a distribution paid directly to
     an Eligible Retirement Plan.

     SECTION 7. ROLLOVERS FROM OTHER PLANS

     If provided by the Employer, the Plan will accept Participant Rollover
     Contributions and/or direct rollovers of distributions made after December
     31, 2001, from the types of plans specified below, beginning on the
     effective date specified below.

     DIRECT ROLLOVERS:

     The Plan will accept a direct rollover of an Eligible Rollover Distribution
     from a qualified plan described in Section 401(a) or 403(a) of the Code,
     excluding after-tax employee contributions; an annuity contract described
     in Section 403(b) of the Code, excluding after-tax employee contributions;
     and an eligible plan under Section 457(b) of the Code which is maintained
     by a state, political subdivision of a state, or any agency or
     instrumentality of a state or political subdivision of a state.

     PARTICIPANT ROLLOVER CONTRIBUTIONS FROM OTHER PLANS:

     The Plan will accept a Participant contribution of an Eligible Rollover
     Distribution from a qualified plan described in Section 401(a) or 403(a) of
     the Code; an annuity contract described in Section 403(b) of the Code; and
     an eligible plan under Section 457(b) of the Code which is maintained by a
     state, political subdivision of a state, or any agency or instrumentality
     of a state or political subdivision of a state.

                                       3.
<PAGE>

     PARTICIPANT ROLLOVER CONTRIBUTIONS FROM IRAS:

     The Plan will accept a Participant rollover contribution of the portion of
     a distribution from an individual retirement account or annuity described
     in Section 408(a) or 408(b) of the Code that is eligible to be rolled over
     and would otherwise be includible in gross income.

     EFFECTIVE DATE OF DIRECT ROLLOVER AND PARTICIPANT ROLLOVER CONTRIBUTION
     PROVISIONS:

     Section 7, Rollovers From Other Plans, shall be effective January 1, 2002.

     SECTION 8. ROLLOVERS DISREGARDED IN INVOLUNTARY CASH-OUTS

     1. APPLICABILITY AND EFFECTIVE DATE. This Section shall apply if elected by
     the Employer and shall be effective as specified below.

     2. ROLLOVERS DISREGARDED IN DETERMINING VALUE OF ACCOUNT BALANCE FOR
     INVOLUNTARY DISTRIBUTIONS. The value of a Participant's nonforfeitable
     Account balance shall be determined without regard to that portion of the
     Account balance that is attributable to Rollover Contributions (and
     earnings allocable thereto) within the meaning of Sections 402(c),
     403(a)(4), 403(b)(8), 408(d)(3)(A)(ii) and 457(e)(16) of the Code. If the
     value of the Participant's nonforfeitable account balance as so determined
     is $5,000 or less, the Plan shall immediately distribute the Participant's
     entire nonforfeitable Account balance. This Section shall apply with
     respect to distributions made after December 31, 2001, with respect to
     Employees who separated from service after December 31, 2001.

     SECTION 9. ELECTIVE DEFERRALS -- CONTRIBUTION LIMITATION

     No Participant shall be permitted to have Elective Deferrals made under
     this Plan, or any other qualified plan maintained by the Employer during
     any taxable year, in excess of the dollar limitation contained in Section
     402(g) of the Code in effect for such taxable year, except to the extent
     permitted under Section 10 of this Amendment and Section 414(v) of the
     Code, if applicable.

     Effective November 1, 2002, the last sentence of Section 4.1(a) of the Plan
     is amended to delete the reference to "a maximum of fifteen percent (15%)"
     and substituting in its place a reference to "the maximum legal limit
     allowed by applicable law."

     SECTION 10. CATCH-UP CONTRIBUTIONS

     All Employees who are eligible to make elective deferrals under this Plan
     and who have attained age 50 before the close of the Plan Year shall be
     eligible to make catch-up contributions in accordance with, and subject to
     the limitations of, Section 414(v) of the Code. Such catch-up contributions
     shall not be taken into account for purposes of the provisions of the Plan
     implementing the required limitations of Sections 402(g) and 415 of the
     Code. The Plan shall not be treated as failing to satisfy the provisions of
     the Plan implementing the requirements of Section 401(k)(3), 401(k)(11),
     401(k)(12), 410(b), or 416 of the Code, as applicable, by reason of the
     making of such catch-up contributions.

                                       4.
<PAGE>

     The over age-50 catch-up contributions shall apply to contributions after
     December 31, 2001.

     SECTION 11. SUSPENSION PERIOD FOLLOWING HARDSHIP DISTRIBUTION

     A Participant who receives a distribution of elective deferrals after
     December 31, 2001 on account of Hardship shall be prohibited from making
     elective deferrals and Employee contributions under this and all other
     plans of the Employer for six months after receipt of the distribution.

     A Participant who receives a distribution of elective deferrals in calendar
     year 2001 on account of Hardship shall be prohibited from making elective
     deferrals and Employee contributions under this and all other plans of the
     Employer for six months after receipt of the distribution or until January
     1, 2002, if later.

     Effective for Hardship distributions made after December 31, 2001, Section
     9.6(b)(4) of the Plan, which limits the amount of Salary Deferral
     Contributions that may be made to the Plan following a Hardship
     distribution, is no longer effective and is deleted from the Plan.

     SECTION 12. DISTRIBUTION UPON SEVERANCE FROM EMPLOYMENT

     1. EFFECTIVE DATE. This Section shall apply for distributions and
     severances from employment occurring after the dates specified below.

     2. NEW DISTRIBUTABLE EVENT. A Participant's elective deferrals, qualified
     nonelective contributions, qualified matching contributions, and earnings
     attributable to these contributions shall be distributed on account of the
     Participant's severance from employment. However, such a distribution shall
     be subject to the other provisions of the Plan regarding distributions,
     other than provisions that require a separation from service before such
     amounts may be distributed.

     This Section, DISTRIBUTION UPON SEVERANCE FROM EMPLOYMENT, shall apply for
     distributions after December 31, 2001, regardless of when the severance
     from employment occurred.

                                       5.
<PAGE>

II. The amendment set forth below is adopted as of the dates set forth herein to
enable the Plan to comply with the revised required minimum distribution rules
under Section 401(a)(9) of the Code:

     SECTION 1. GENERAL RULES.

     1.1 EFFECTIVE DATE. Unless an earlier Effective Date is specified, the
     provisions of this Amendment will apply for purposes of determining
     required minimum distributions for calendar years beginning with the 2003
     calendar year.

     1.2 PRECEDENCE. The requirements of this Amendment will take precedence
     over any inconsistent provisions of the Plan.

     1.3 REQUIREMENTS OF TREASURY REGULATIONS INCORPORATED. All distributions
     required under this Amendment will be determined and made in accordance
     with the Treasury Regulations under Section 401(a)(9) of the Code.

     1.4 TEFRA SECTION 242(b)(2) ELECTIONS. Notwithstanding the other provisions
     of this Amendment, distributions may be made under a designation made
     before January 1, 1984, in accordance with Section 242(b)(2) of the Tax
     Equity and Fiscal Responsibility Act ("TEFRA") and the provisions of the
     Plan that relate to Section 242(b)(2) of TEFRA.

     SECTION 2. TIME AND MANNER OF DISTRIBUTION.

     2.1 REQUIRED BEGINNING DATE. The Participant's entire interest will be
     distributed, or begin to be distributed, to the Participant no later than
     the Participant's Required Beginning Date.

     2.2 DEATH OF PARTICIPANT BEFORE DISTRIBUTIONS BEGIN. If the Participant
     dies before distributions begin, the Participant's entire interest will be
     distributed, or begin to be distributed, no later than as follows:

     (a) if the Participant's surviving spouse is the Participant's sole
     Designated Beneficiary, then, except as otherwise provided in Section 4.2
     of this Amendment, distributions to the surviving spouse will begin by
     December 31 of the calendar year immediately following the calendar year in
     which the Participant died, or by December 31 of the calendar year in which
     the Participant would have attained age seventy and one-half (70 1/2), if
     later.

     (b) if the Participant's surviving spouse is not the Participant's sole
     Designated Beneficiary, then, except as otherwise provided in Section 4.2
     of this Amendment, distributions to the Designated Beneficiary will begin
     by December 31 of the calendar year immediately following the calendar year
     in which the Participant died.

     (c) if there is no Designated Beneficiary as of September 30 of the year
     following the year of the Participant's death, the Participant's entire
     interest will be distributed by December 31 of the calendar year containing
     the fifth anniversary of the Participant's death.

     (d) if the Participant's surviving spouse is the Participant's sole
     Designated Beneficiary and the surviving spouse dies after the Participant
     but before distributions to the surviving spouse begin, this Section 2.2,
     other than Section 2.2(a), will apply as if the surviving spouse were the
     Participant.

                                       6.
<PAGE>

     For purposes of this Section 2.2 and Section 4.2 of this Amendment, unless
     Section 2.2(d) applies, distributions are considered to begin on the
     Participant's Required Beginning Date. If Section 2.2(d) applies,
     distributions are considered to begin on the date distributions are
     required to begin to the surviving spouse under Section 2.2(a). If
     distributions under an annuity purchased from an insurance company
     irrevocably commence to the Participant before the Participant's Required
     Beginning Date (or to the Participant's surviving spouse before the date
     distributions are required to begin to the surviving spouse under Section
     2.2(a)), the date distributions are considered to begin is the date
     distributions actually commence.

     2.3 FORMS OF DISTRIBUTION. Unless the Participant's interest is distributed
     in the form of an annuity purchased from an insurance company or in a
     single sum on or before the Required Beginning Date, as of the first
     distribution calendar year distributions will be made in accordance with
     Sections 3 and 4 of this Amendment. If the Participant's interest is
     distributed in the form of an annuity purchased from an insurance company,
     distributions thereunder will be made in accordance with the requirements
     of Section 401(a)(9) of the Code and the Treasury Regulations.

     SECTION 3. REQUIRED MINIMUM DISTRIBUTIONS DURING PARTICIPANT'S LIFETIME.

     3.1 AMOUNT OF REQUIRED MINIMUM DISTRIBUTION FOR EACH DISTRIBUTION CALENDAR
     YEAR. During the Participant's lifetime, the minimum amount that will be
     distributed for each distribution calendar year is the lesser of:

     (a) the quotient obtained by dividing the Participant's account balance by
     the distribution period in the Uniform Lifetime Table set forth in Section
     1.401(a)(9)-9 of the Treasury Regulations, using the Participant's age as
     of the Participant's birthday in the distribution calendar year; or

     (b) if the Participant's sole Designated Beneficiary for the distribution
     calendar year is the Participant's spouse, the quotient obtained by
     dividing the Participant's account balance by the number in the Joint and
     Last Survivor Table set forth in Section 1.401(a)(9)-9 of the Treasury
     Regulations, using the Participant's and spouse's attained ages as of the
     Participant's and spouse's birthdays in the distribution calendar year.

     3.2 LIFETIME REQUIRED MINIMUM DISTRIBUTIONS CONTINUE THROUGH YEAR OF
     PARTICIPANT'S DEATH. Required minimum distributions will be determined
     under this Section 3.2 beginning with the first distribution calendar year
     and up to and including the distribution calendar year that includes the
     Participant's date of death.

     SECTION 4. REQUIRED MINIMUM DISTRIBUTIONS AFTER PARTICIPANT'S DEATH.

     4.1 DEATH ON OR AFTER DATE DISTRIBUTIONS BEGIN.

     (a) PARTICIPANT SURVIVED BY DESIGNATED BENEFICIARY. If the Participant dies
     on or after the date distributions begin and there is a Designated
     Beneficiary, the minimum amount that will be distributed for each
     distribution calendar year after the year of the Participant's death is the
     quotient obtained by dividing the Participant's account balance by the
     longer of the remaining life expectancy of the Participant or the remaining
     life expectancy of the Participant's Designated Beneficiary, determined as
     follows:

                                       7.
<PAGE>

     (i) the Participant's remaining life expectancy is calculated using the age
     of the Participant in the year of death, reduced by one for each subsequent
     year.

     (ii) if the Participant's surviving spouse is the Participant's sole
     Designated Beneficiary, the remaining life expectancy of the surviving
     spouse is calculated for each distribution calendar year after the year of
     the Participant's death using the surviving spouse's age as of the spouse's
     birthday in that year. For distribution calendar years after the year of
     the surviving spouse's death, the remaining life expectancy of the
     surviving spouse is calculated using the age of the surviving spouse as of
     the spouse's birthday in the calendar year of the spouse's death, reduced
     by one for each subsequent calendar year.

     (iii)if the Participant's surviving spouse is not the Participant's sole
     Designated Beneficiary, the Designated Beneficiary's remaining life
     expectancy is calculated using the age of the beneficiary in the year
     following the year of the Participant's death, reduced by one for each
     subsequent year.

     (b) NO DESIGNATED BENEFICIARY. If the Participant dies on or after the date
     distributions begin and there is no Designated Beneficiary as of September
     30 of the year after the year of the Participant's death, the minimum
     amount that will be distributed for each distribution calendar year after
     the year of the Participant's death is the quotient obtained by dividing
     the Participant's account balance by the Participant's remaining life
     expectancy calculated using the age of the Participant in the year of
     death, reduced by one for each subsequent year.

     4.2 DEATH BEFORE DATE DISTRIBUTIONS BEGIN.

     (a) PARTICIPANT SURVIVED BY DESIGNATED BENEFICIARY. If the Participant dies
     before the date distributions begin and there is a Designated Beneficiary,
     the minimum amount that will be distributed for each distribution calendar
     year after the year of the Participant's death is the quotient obtained by
     dividing the Participant's account balance by the remaining life expectancy
     of the Participant's Designated Beneficiary, determined as provided in
     Section 4.1 above.

     Alternatively, if the Participant dies before distributions begin and there
     is a Designated Beneficiary, distribution to the Designated Beneficiary is
     not required to begin by the date specified in Section 2.2 above, but the
     Participant's entire interest will be distributed to the Designated
     Beneficiary by December 31 of the calendar year containing the fifth
     anniversary of the Participant's death. If the Participant's surviving
     spouse is the Participant's sole Designated Beneficiary and the surviving
     spouse dies after the Participant but before distributions to either the
     Participant or the surviving spouse begin, this election will apply as if
     the surviving spouse were the Participant.

     Participants or beneficiaries may elect on an individual basis whether the
     5-year rule or the life expectancy rule in Sections 2.2 and 4.2 of this
     Amendment applies to distributions after the death of a Participant who has
     a Designated Beneficiary. The election must be made no later than the
     earlier of September 30 of the calendar year in which distribution would be
     required to begin under Section 2.2 above, or by September 30 of the
     calendar year which contains the fifth anniversary of the Participant's
     (or, if applicable, surviving spouse's) death. If neither the Participant
     nor beneficiary makes an election under this paragraph, distributions will
     be made in accordance with Section 2.2 and the first paragraph of Section
     4.2(a) of this Amendment. This election will apply to all distributions.

                                       8.
<PAGE>

     A Designated Beneficiary who is receiving payments under the 5-year rule
     may make a new election to receive payments under the life expectancy rule
     until December 31, 2003, provided that all amounts that would have been
     required to be distributed under the life expectancy rule for all
     distribution calendar years before 2004 are distributed by the earlier of
     December 31, 2003 or the end of the 5-year period.

     (b) NO DESIGNATED BENEFICIARY. If the Participant dies before the date
     distributions begin and there is no Designated Beneficiary as of September
     30 of the year following the year of the Participant's death, distribution
     of the Participant's entire interest will be completed by December 31 of
     the calendar year containing the fifth anniversary of the Participant's
     death.

     (c) DEATH OF SURVIVING SPOUSE BEFORE DISTRIBUTIONS TO SURVIVING SPOUSE ARE
     REQUIRED TO BEGIN. If the Participant dies before the date distributions
     begin, the Participant's surviving spouse is the Participant's sole
     Designated Beneficiary, and the surviving spouse dies before distributions
     are required to begin to the surviving spouse under Section 2.2(a), this
     Section 4.2 will apply as if the surviving spouse were the Participant.

     SECTION 5. DEFINITIONS.

     5.1 DESIGNATED BENEFICIARY. The individual who is designated as the
     beneficiary under Sections 2.5 and 8.8 of the Plan and is the Designated
     Beneficiary under Section 401(a)(9) of the Code and Section 1.401(a)(9)-1,
     Q&A-4, of the Treasury Regulations.

     5.2 DISTRIBUTION CALENDAR YEAR. A "Distribution Calendar Year" is defined
     as a calendar year for which a minimum distribution is required. For
     distributions beginning before the Participant's death, the first
     distribution calendar year is the calendar year immediately preceding the
     calendar year which contains the Participant's Required Beginning Date. For
     distributions beginning after the Participant's death, the first
     distribution calendar year is the calendar year in which distributions are
     required to begin under Section 2.2 above. The required minimum
     distribution for the Participant's first distribution calendar year will be
     made on or before the Participant's Required Beginning Date. The required
     minimum distribution for other distribution calendar years, including the
     required minimum distribution for the distribution calendar year in which
     the Participant's Required Beginning Date occurs, will be made on or before
     December 31 of that distribution calendar year.

     5.3 LIFE EXPECTANCY. Life Expectancy as computed by use of the Single Life
     Table in Section 1.401(a)(9)-9 of the Treasury Regulations.

     5.4 PARTICIPANT'S ACCOUNT BALANCE. The account balance as of the last
     valuation date in the calendar year immediately preceding the distribution
     calendar year (valuation calendar year) increased by the amount of any
     contributions made and allocated or forfeitures allocated to the account
     balance as of dates in the valuation calendar year after the valuation date
     and decreased by distributions made in the valuation calendar year after
     the valuation date. The account balance for the valuation calendar year
     includes any amounts rolled over or transferred to the Plan either in the
     valuation calendar year or in the distribution calendar year if distributed
     or transferred in the valuation calendar year.

     5.5 REQUIRED BEGINNING DATE. The date specified in Section 2.44 of the
     Plan.

                                       9.
<PAGE>

     IN WITNESS WHEREOF, this Second Amendment is executed this 16th day of
     December, 2002.

                                        CORVAS INTERNATIONAL, INC.

                                        By: /s/ Carolyn M. Felzer
                                           -------------------------------------
                                        Printed Name: Carolyn M. Felzer
                                        Title: Vice President and Controller

                                      10.<PAGE>

                                                                   EXHIBIT 10.53

                                  AMENDMENT TO
                           CORVAS INTERNATIONAL, INC.
                           2000 EQUITY INCENTIVE PLAN
              APPROVED BY THE BOARD OF DIRECTORS FEBRUARY 24, 2003

         WHEREAS, Corvas International, Inc. (the "Company") previously adopted
the Corvas International, Inc. 2000 Equity Incentive Plan (the "Plan"); and

         WHEREAS, Section 13 of the Plan provides that the Plan may be amended
by the Board of Directors of the Company and that the provisions relating to
Options granted to Directors who are not Employees may be amended once every six
months.

         NOW, THEREFORE, the Plan is amended as follows:

         1. Section 7 of the Plan is amended to add the following additional
paragraph to the end of Section 7:

                  "(f) Notwithstanding Section 7(e) of the Plan or any other
provision of the Plan or any relevant Option Agreement, the Options to purchase
an aggregate of 48,000 shares of Common Stock granted on January 2, 2003 to the
Directors who are not Employees, in the amounts and with the exercise price set
forth on EXHIBIT A attached hereto shall become fully vested and exercisable on
the closing of a corporate transaction described in Section 12(c) of the Plan."

<PAGE>

                                                   EXHIBIT A

<TABLE>
<CAPTION>

----------------------------------- ---------------------- ------------------------ ------------------ ----------------
               NAME                      GRANT DATE              GRANT TYPE          OPTIONS GRANTED    OPTION PRICE
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
<S>                                       <C>                   <C>                       <C>             <C>
Susan B. Bayh                             1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
M. Blake Ingle                            1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
J. Stuart Mackintosh                      1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
Burton E. Sobel                           1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
Michael Sorell                            1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
Nicole Vitullo                            1/2/2003              Non-Qualified             8,000           $1.338800
----------------------------------- ---------------------- ------------------------ ------------------ ----------------
</TABLE>

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