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                         LA JOLLA PHARMACEUTICAL COMPANY
                                  EXHIBIT 10.42

February 9, 2001

Theodora Reilly
La Jolla Pharmaceutical Company
6455 Nancy Ridge Drive
San Diego, CA  92121

Re: Severance Agreement

Dear Theodora,

        As a supplement to the offer letter and agreement dated August 13, 1998
between La Jolla Pharmaceutical Company ("LJP") and Theodora Reilly ("Reilly")
related to Reilly's employment by LJP, Reilly and LJP hereby agree as follows:

        In connection with her employment with LJP, Reilly's new title will be
Vice President of Human Resources.

        If Reilly's employment is terminated by LJP without cause (as defined
below), or if a Change in Control of LJP (as defined below) occurs and Reilly's
employment with LJP or its successor "terminates in connection with" (as defined
below) that Change in Control and in the absence of any event or circumstance
constituting Cause, then:

          (i)       Reilly will be entitled to receive from LJP a severance
                    payment equal to her then-current base salary for a period
                    of six full calendar months from the date of termination and
                    an additional three full calendar months if and when after
                    the first six months she has not found suitable employment,
                    payable consistent with LJP's normal payroll practices,
                    provided that such payment will be contingent upon execution
                    and delivery by Reilly and LJP of a mutual release, in form
                    satisfactory to LJP, of all claims arising in connection
                    with Reilly's employment with LJP and termination thereof,
                    and

          (ii)      Reilly will be entitled to receive for a period of six full
                    calendar months from the date of termination and an
                    additional three full calendar months if and when after the
                    first six months she has not found suitable employment,
                    medical and dental benefits coverage for Reilly and/or her
                    dependents through the Company's available plans at the time
                    and Reilly will be responsible to continue payment of all
                    applicable deductions for premium costs. After the Company's
                    obligation to pay the premiums for health and dental
                    coverage Reilly and/or her dependents will be eligible to
                    continue plan participation under COBRA.

          (iii)     Notwithstanding anything to the contrary in the option plan
                    (the "PLAN") pursuant to which all of Reilly's existing
                    options were granted, the Options shall automatically vest
                    and become fully exercisable as of the date of

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                    termination of Executive's employment (the TERMINATION
                    DATE"), notwithstanding any vesting or performance
                    conditions applicable thereto, and shall remain exercisable
                    for a period of one year following the Termination Date or
                    such longer period as is provided by the Plan or grant
                    pursuant to which the Options were granted. However,
                    notwithstanding the foregoing, in no case will the Options
                    be exercisable beyond the duration of the original term
                    thereof, and if the Options qualify as an incentive stock
                    option under the Internal Revenue Code and applicable
                    regulations thereunder, the exercise period thereof shall
                    not be extended in such a manner as to cause the Options to
                    cease to qualify as an incentive stock option unless
                    Executive elects to forego incentive stock option treatment
                    and extend the exercise period thereof as provided herein.

        For purposes hereof, "CHANGE IN CONTROL" of LJP has the meaning set
        forth in the Plan in its form as the date of grant of the Options.

        For purposes hereof, "CAUSE" means Reilly has (i) engaged in serious
        criminal activity or other wrongful conduct that has an adverse impact
        on LJP, (ii) disregarded instructions given to him under the authority
        of LJP's Board of Directors, (iii) performed services for any person or
        entity other than LJP and appropriate civic organizations, or (iv)
        otherwise materially breached her employment or fiduciary
        responsibilities to LJP.

        For purposes hereof, Reilly's employment with LJP or its successor will
        be deemed to "TERMINATE IN CONNECTION WITH" a Change in Control if,
        within 180 days after the consummation of the Change of Control, (i)
        Reilly is removed from Reilly's employment by, or resigns her employment
        upon the request of, a person exercising practical voting control over
        LJP or its successor following the Change in Control or a person acting
        upon authority or at the instruction of such person; or (ii) Reilly's
        position is eliminated as a result of a reduction in force made to
        reduce over-capacity or unnecessary duplication of personnel and Reilly
        is not offered a replacement position with LJP or its successor as a
        Vice President with compensation and functional duties substantially
        similar to the compensation and duties in effect immediately before the
        Change in Control; or (iii) Reilly resigns her employment with the
        Company or its successor rather than comply with a relocation of her
        primary work site more than 50 miles from LJP's headquarters.

               In Witness Whereof, LJP and Reilly have entered into this
        agreement as of May 18, 2001.

        LA JOLLA PHARMACEUTICAL COMPANY

        By: /s/ STEVEN B. ENGLE             /s/  THEODORA REILLY
           ----------------------------    -----------------------------------
                Steven B. Engle            Theodora Reilly
                Chairman & CEO             Vice President of Human Resources<PAGE>   1

                         LA JOLLA PHARMACEUTICAL COMPANY
                                  EXHIBIT 10.43

February 9, 2001

Paul Jenn, Ph.D.
La Jolla Pharmaceutical Company
6455 Nancy Ridge Drive
San Diego, CA  92121

Re: Severance Agreement

Dear Paul,

        As a supplement to the offer letter and agreement dated September 8,
1994 between La Jolla Pharmaceutical Company ("LJP") and Paul Jenn, Ph.D.
("Jenn") related to Jenn's employment by LJP, Jenn and LJP hereby agree as
follows:

        In connection with his employment with LJP, Jenn's new title will be
Vice President of Operations.

        If Jenn's employment is terminated by LJP without cause (as defined
below), or if a Change in Control of LJP (as defined below) occurs and Jenn's
employment with LJP or its successor "terminates in connection with" (as defined
below) that Change in Control and in the absence of any event or circumstance
constituting Cause, then:

          (i)       Jenn will be entitled to receive from LJP a severance
                    payment equal to his then-current base salary for a period
                    of six full calendar months from the date of termination and
                    an additional three full calendar months if and when after
                    the first six months he has not found suitable employment,
                    payable consistent with LJP's normal payroll practices,
                    provided that such payment will be contingent upon execution
                    and delivery by Jenn and LJP of a mutual release, in form
                    satisfactory to LJP, of all claims arising in connection
                    with Jenn's employment with LJP and termination thereof, and

          (ii)      Jenn will be entitled to receive for a period of six full
                    calendar months from the date of termination and an
                    additional three full calendar months if and when after the
                    first six months he has not found suitable employment,
                    medical and dental benefits coverage for Jenn and/or his
                    dependents through the Company's available plans at the time
                    and Jenn will be responsible to continue payment of all
                    applicable deductions for premium costs. After the Company's
                    obligation to pay the premiums for health and dental
                    coverage Jenn and/or his dependents will be eligible to
                    continue plan participation under COBRA.

          (iii)     Notwithstanding anything to the contrary in the option plan
                    (the "PLAN") pursuant to which all of Jenn's existing
                    options were granted, the Options shall automatically vest
                    and become fully exercisable as of the date of termination
                    of Executive's employment (the TERMINATION DATE"),

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                    notwithstanding any vesting or performance conditions
                    applicable thereto, and shall remain exercisable for a
                    period of one year following the Termination Date or such
                    longer period as is provided by the Plan or grant pursuant
                    to which the Options were granted. However, notwithstanding
                    the foregoing, in no case will the Options be exercisable
                    beyond the duration of the original term thereof, and if the
                    Options qualify as an incentive stock option under the
                    Internal Revenue Code and applicable regulations thereunder,
                    the exercise period thereof shall not be extended in such a
                    manner as to cause the Options to cease to qualify as an
                    incentive stock option unless Executive elects to forego
                    incentive stock option treatment and extend the exercise
                    period thereof as provided herein.

        For purposes hereof, "CHANGE IN CONTROL" of LJP has the meaning set
        forth in the Plan in its form as the date of grant of the Options.

        For purposes hereof, "CAUSE" means Jenn has (i) engaged in serious
        criminal activity or other wrongful conduct that has an adverse impact
        on LJP, (ii) disregarded instructions given to him under the authority
        of LJP's Board of Directors, (iii) performed services for any person or
        entity other than LJP and appropriate civic organizations, or (iv)
        otherwise materially breached his employment or fiduciary
        responsibilities to LJP.

        For purposes hereof, Jenn's employment with LJP or its successor will be
        deemed to "TERMINATE IN CONNECTION WITH" a Change in Control if, within
        180 days after the consummation of the Change of Control, (i) Jenn is
        removed from Jenn's employment by, or resigns his employment upon the
        request of, a person exercising practical voting control over LJP or its
        successor following the Change in Control or a person acting upon
        authority or at the instruction of such person; or (ii) Jenn's position
        is eliminated as a result of a reduction in force made to reduce
        over-capacity or unnecessary duplication of personnel and Jenn is not
        offered a replacement position with LJP or its successor as a Vice
        President with compensation and functional duties substantially similar
        to the compensation and duties in effect immediately before the Change
        in Control; or (iii) Jenn resigns his employment with the Company or its
        successor rather than comply with a relocation of his primary work site
        more than 50 miles from LJP's headquarters.

               In Witness Whereof, LJP and Jenn have entered into this agreement
        as of May 18, 2001.

        LA JOLLA PHARMACEUTICAL COMPANY

        By: /s/ STEVEN B. ENGLE                   /s/ PAUL JENN
           ------------------------------         ----------------------------
                Steven B. Engle                   Paul Jenn, Ph.D.
                Chairman & CEO                    Vice President of Operations

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