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                                                               Exhibit 10.13

                              AMENDED AND RESTATED
                        IDEC PHARMACEUTICALS CORPORATION
                           DEFERRED COMPENSATION PLAN

THIS AMENDED AND RESTATED DEFERRED COMPENSATION PLAN is adopted by IDEC
Pharmaceuticals Corporation a Delaware corporation (the "Company"), effective
as of September 5, 2001, with reference to the following:

    A.   The Company established a Deferred Compensation Plan effective
         January 1, 1999 (the "Original Plan") to provide key employees and
         non-employee Board members a tax deferred, capital accumulation,
         retention program.

    B.   The Company desires to amend and restate the Original Plan as set forth
         herein.

    C.   This Plan is intended to provide benefits to a select group of
         management or highly compensated personnel in order to attract and
         retain the highest quality executives. This Plan is NOT intended to be
         a qualified plan within the meaning of sections 401(a) and 501(a) of
         the Internal Revenue Code of 1986, as amended (the "Code").

    D.   This Plan is intended to be an unfunded plan for purposes of the
         Employee Retirement Income Security act of 1975, as amended ("ERISA").

NOW, THEREFORE, the Company hereby adopts the IDEC Pharmaceuticals
Corporation Deferred Compensation Plan on the following terms and conditions:

    1.0  Definitions. Whenever used in this Plan, the following words and
         phrases shall have the same meaning set forth below, unless a different
         meaning is expressly provided or plainly required by the context in
         which the words or phrases are used:

    1.1  Beneficiary means a person designated by a Participant to receive
         Plan benefits in the event of the Participant's death.

    1.2  Board means the Board of Directors of the Company and its successors.

    1.3  Controller means the Vice President and Controller of the Company and
         their successors.

    1.4  Change in Control of Company means:

       (A) a change in ownership, or power to vote such that 35% or more of the
           voting stock of the Company is concentrated in the hands of any one
           person, entity or group of related persons or entities or group of
           persons or entities acting in concert;

       (B) a change in the composition of the Board as a result of which
           individuals serving on the Board immediately prior to such change
           cease to constitute at least a majority thereof;

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       (C) the stockholders of the Company approved any plan or proposal for the
           liquidation or dissolution of the Company;

       (D) substantially all of the assets of the Company are sold or otherwise
           transferred to parties that are not within the "controlled group or
           corporations" (as defined in section 1563 of the Internal Revenue
           Code of 1986) in which the Company is a member.

    1.5  Company means IDEC Pharmaceuticals Corporation a Delaware corporation

    1.6  Disability means:

       (A) "disability" as defined in any group long-term disability policy or
           program sponsored by the Company and in effect at the time a
           Participant who has suffered a physical or mental impairment makes
           application under this Plan for a disability distribution, or

       (B) if no such policy or program is in force at such time, "disability"
           as defined in section 1392c(a)(3) of volume 42 of the United States
           Code and regulations promulgated thereunder, provided, however, that
           the disability (whether under the definition in (a) or in (b)) must
           be of a duration of at least six (6) consecutive months from the
           date the Participant suffers the disability notwithstanding any
           different requirements of duration under either definition in the
           actual policy or program or in the United States Code, respectively.

           A Participant who has suffered a Disability shall be disabled within
           the meaning of this Section 1.6.

           The determination of whether a Participant is disabled within the
           meaning of this Section 1.6 shall be made by the Controller. A
           Participant who believes they have suffered a disability within the
           meaning of this Section 1.6 shall make application to the Controller,
           on a form prescribed by the Controller, for a determination of
           whether they are disabled under the terms of this Section 1.6. The
           Participant shall make such written application to the Controller on
           or after the date which is at least five (5) consecutive months
           following the date they first suffered the impairment under
           consideration. Any determination by the Controller that a disability
           exists under the provisions of this Section 1.6 shall be effective
           only after the date the disability has existed for six
           (6) consecutive months. All determinations made by the Controller
           shall be final, and no Participant shall be considered disabled for
           any purpose whatsoever under the provisions of this Plan if
           determined not to be disabled by the Controller under the procedures
           set forth in this Section 1.6.

           The Controller shall notify each Participant who has made application
           under this Section 1.6, in writing, for their determination within
           three (3) months of the date the Controller receives the
           Participant's application hereunder. The Participant shall cooperate
           in providing any information to the Controller which it requires in
           making its determination, including, but not limited to, access to
           the Participant's medical records, direct contact with their
           physician and physical examination by a physician

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           selected by the Company. Any Participant who does not fully
           cooperate shall be deemed not disabled by the Controller and so
           notified.

    1.7  KEY EMPLOYEE means an employee of the Company, selected by the
         Controller, who is a member of a select group of management or highly
         compensated employees within the meaning of Section 2520.104-23 of the
         Department of Labor ERISA Regulations.

    1.8  NORMAL RETIREMENT AGE means the later of age 60 or five years of
         participation in this Plan.

    1.9  PARTICIPANT means:

       (A) a key employee designated by the Controller, in writing, to
           participate in the benefits under the Plan who timely files a written
           election pursuant to Section 2.4, below, and

       (B) a former Employee who, at the time of their termination from
           employment, retirement, death or occurrence of disability, retains,
           or whose beneficiary retains, benefits earned under the Plan in
           accordance with its terms. A Participant is considered an active
           participant in the Plan until the earliest of the following:

            (i) the Participant retires, dies or becomes disabled under the
                terms of this Plan; or

            (ii) the Participant is determined or believed by the Controller to
                 no longer qualify as a member of a "select group of highly
                 compensated or management employees" and such Participant has
                 received distribution of their entire benefit hereunder; or

           (iii) the participant terminates employment with the Company.

    1.10 PLAN means the Amended and Restated IDEC Pharmaceuticals Corporation
         Deferred Compensation Plan established by this document.

    1.11 PLAN COMMITTEE means a Committee appointed by the Controller, which
         generally includes a representative from Human Resources.

    1.12 PLAN YEAR means the period which is the same as the calendar year.

    1.13 PLAN YEAR COMPENSATION means the total income paid to an active
         Participant by the Company during any Plan Year, or portion thereof in
         which they are a Participant in this Plan, as reflected on the
         Participant's form W-2. For purposes of the elections under Section 2.4
         of this Plan, Plan Year Compensation shall consist of one or more of
         the following types of income: annual base salary or annual bonus.

    2.0  PARTICIPATION.

    2.1  ELIGIBILITY. A Key Employee of the Company is eligible to participate
         in this Plan on the entry date first following the date as of which all
         of the following events have occurred:

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       (A) the Controller has designated an individual in writing as a
           Participant in the Plan, and

       (B) the Key Employee has made a written election in accordance with the
           terms of Section 2.4 below.

       (C) the Key Employee has completed 30 days of employment with IDEC
           Pharmaceuticals Corporation

    2.2 ENTRY DATE. Any Key Employee who has met the eligibility requirements
       specified in Section 2.1 as of the effective date of this Plan shall
       become a Participant in the Plan as of the first day of the succeeding
       calendar quarter i.e. April 1, July 1, October 1 and January 1 following
       their hire date or promotion date. Any Key Employee of the Company who
       meets the eligibility requirements specified in Section 2.1 after the
       effective date of this Plan shall become a Participant in the Plan
       immediately upon the date on which they have met the eligibility
       requirements.

    2.3 DESIGNATION. The Controller shall designate for each Plan Year, in
       writing, the name of each Key Employee who shall be entitled to
       participate in the Plan for the Plan Year. Such designation by the
       Controller shall occur on a date such that each designated Key Employee
       shall have sufficient time to make their written election as required by
       Section 2.4 below.

    2.4 WRITTEN ELECTION BY PARTICIPANT. Each Key Employee designated by the
       Controller as a Participant for a Plan Year shall submit a written
       election prior to the entry date of the Plan Year in which they will be a
       Participant.

       (A) Such written election shall be made on the form presented to the Key
           Employee by the Plan Committee and shall set forth:

            (i) their election to participate in this Plan under the terms
                hereof;

            (ii) the amount of Plan Year Compensation the Key Employee has
                 determined to defer under the Plan for the Plan Year, pursuant
                 to Section 3.1 below;

           (iii) the date on which their benefit is to be distributed which is
                 the earlier of (a) the date specified for an In-Service
                 Withdrawal or (b) the later of (i) a specific date or
                 (ii) when they terminate employment with the Company due to
                 termination of service, retirement, disability or death;

            (iv) the form in which their benefit is to be distributed upon
                 termination of service or retirement.

       (B) A Participant's most recently submitted written election shall remain
           in effect for subsequent Plan Years until the Participant changes it
           in accordance with the following:

            (i) A Participant may change the amount of Plan Year Compensation
                they will defer under the Plan for future Plan Years by
                submitting a new written election to the Company. Such new
                election must be submitted to the Company on or before the
                seventh (7th) day immediately proceeding the Plan Year for which
                the new election

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                is to be effective. Any election of the amount of Plan Year
                Compensation to defer for a given Plan Year shall be
                irrevocable on and after the first day of the Plan Year for
                which the election was made.

            (ii) A Participant may change the date or form of distribution by
                 submitting a new written election to the Company, provided that
                 such change is submitted at least sixty (60) days prior to the
                 original date of distribution, the new date of distribution is
                 subsequent to the original date of distribution, and only one
                 change may be made after the original election.

    2.5 DURATION OF PARTICIPANT. Any Key Employee who has become a Participant
       at any time shall remain a Participant, even though they are no longer an
       active Participant, until their entire benefit under the terms of the
       Plan has been paid to them (or to their Beneficiary in the event of their
       death), at which time they cease to be a Participant.

    2.6 MAINTENANCE OF RECORDS. The annual Designation of Participants by the
       Controller as required by Section 2.4 shall be maintained with all other
       files pertaining to this Plan.

    3.0 CONTRIBUTIONS AND ALLOCATIONS.

    3.1 PARTICIPANT CONTRIBUTIONS. A Participant may elect to defer each Plan
       Year a portion, up to 80%, of their Plan Year Compensation, provided that
       a Participant may not defer an amount less than the minimum established
       from year to year by the Controller. For the initial Plan Year, such
       minimum shall be $5,000. In the event a participant enters the plan on a
       date other than January 1, the amount of the deferral election will be
       prorated over the balance of that calendar year to determine the minimum
       deferral. Such election shall designate the amount of income deferred
       during the Plan Year, in actual dollar amounts or percentages. Once a
       Participant's contributions for a Plan Year reach their elected dollar
       amount or percentages, such Participant shall not be allowed to defer
       additional portions of their Plan Year Compensation for the remainder of
       the Plan Year. Any deferred amounts in excess of their elected dollar
       amount shall be refunded to the Participant as soon as practicable.

    3.2 ALLOCATION OF CONTRIBUTIONS. All amounts which a Participant elects to
       defer under the terms of this Plan shall be allocated to their Account.
       Each such Participant Account shall be credited with earnings as provided
       in Section 3.3 below.

    3.3 CREDITED EARNINGS. The account of each Participant shall be credited
       with interest. During the first five years of participation in the Plan
       by a Participant the account will be credited with interest at a rate of
       7% per annum compounded quarterly. Upon completion of five years of
       participation in the plan by the Participant the Participant's account
       will be credited 9% per annum compounded annually. Additionally the
       interest rate of 9% will be applied retroactively to all contributions
       made during the first five years of participation. The Company has the
       right to modify these rates on an annual basis.


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    3.4 FORFEITURES. If any amount of Participants contributions are forfeited
       in any year, such forfeited amounts shall be returned to the Company.

    3.5 FUNDING. The assets of the Plan shall be held by the Company. As such,
       the Plan is intended to be an unfunded plan for purposes of the
       requirements of ERISA and the Code.

       Notwithstanding the provisions under the terms of the Plan the amounts
       contributed to this Plan, plus earnings thereon, shall be allocated to
       separate accounts of Participants, all such amounts credited to such
       individual accounts shall remain the general assets of the Employer, and
       as such shall remain subject to the claims of the general creditors of
       the Company. This Plan does not create, nor does any Employee,
       Participant or Beneficiary have, any right with respect to any specific
       assets of the Company or the Plan.

    4.0 VESTING OF ACCOUNTS. The Account of each Participant shall be 100%
       vested in such Participant at all times, provided that a portion of such
       accounts shall be forfeited in accordance with Unplanned In-Service
       Distribution of Section 6.3.

    5.0 TYPES OF BENEFITS.

    5.1 RETIREMENT BENEFIT. A Participant's Retirement Benefit is the unpaid
       balance of their Account which equals the total of all contributions made
       by the Participant and allocated to their account and all earnings
       credited to their account in accordance with the terms of the Plan less
       any distributions already paid.

    5.2 TERMINATION OF SERVICE BENEFIT. If a Participant elects to receive their
       retirement benefit upon termination of their employment with the Company,
       or if a Participant's employment with the Company terminates prior to
       distribution of their In-Service Benefit, the Company will pay a
       retirement benefit, calculated under Section 5.1, under the applicable
       form elected by the Participant in their written election.

    5.3 DISABILITY BENEFIT. If a Participant becomes disabled as defined in
       Section 1.5 above, the Company will pay their retirement benefit,
       calculated under Section 5.1, under the applicable form elected by the
       Participant in their written election.

    5.4 DEATH BENEFIT.

       (A) If a Participant dies after a distribution has commenced or if the
           Company has not purchased a life insurance contract in connection
           with the Participant's Retirement Benefit, the Company will continue
           the payments of such distribution otherwise due to the Participant to
           their designation Beneficiary, under the applicable form elected by
           the participant in their written election.

       (B) If a Participant dies while still employed by the Company and the
           Company has purchased a life insurance contract in connection with
           such Participant's Retirement Benefit, the Company will pay the
           Participant's designated Beneficiary the greater of their Retirement
           Benefit as determined under Section 5.1 above or their projected
           retirement benefit (as defined below), under the applicable form
           elected by the Participant in

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           their written election. "Projected Retirement Benefit" means the
           amount determined by projecting the Participant's contribution for
           the Participant's first year of participation hereunder at an
           assumed earnings rate of 9% to retirement at normal retirement age.

    5.5 IN-SERVICE WITHDRAWAL. A Participant may designate a date in the future
       for receipt of an in-Service Withdrawal with respect to the Participant's
       contribution for a given Plan Year. Such withdrawal may be paid while the
       Participant remains employed with the Company, but shall be paid without
       credited earnings attributable to such Participant Contribution (which
       credited earnings shall be distributed upon termination of employment or
       retirement) in four (4) equal yearly installments commencing on
       January 15 of the fourth Plan Year following the Plan Year of deferral
       (the "In-Service Commencement Year"); provided, however, that a
       Participant may elect to defer commencement of an In-Service Withdrawal
       for an additional three years by delivery to the Company of a written
       election not later than the last day of the Plan year prior to the Plan
       Year immediately preceding the In-Service Commencement Year.

    5.6 UNPLANNED IN-SERVICE BENEFIT. A Participant may elect to receive their
       Retirement Benefit as an Unplanned In-Service Benefit at any time by
       providing the Plan Committee with a written election to do so. In
       consideration for receiving an Unplanned in-Service Benefit, such
       Participant shall permanently forfeit an amount equal to ten percent
       (10%) of their retirement benefit and forgo all future participation in
       the Plan.

    5.7 FINANCIAL HARDSHIP BENEFIT. A Participant may request a portion of their
       retirement benefit as a financial hardship benefit at any time by
       providing the Plan Committee, to its satisfaction, with a written
       election to do so, proof of an unforeseeable financial hardship, and
       proof that all other financial resources have been explored and utilized.
       The amount of a financial hardship benefit shall be limited to the lesser
       of the amount needed for the financial hardship or such Participant's
       retirement benefit. In consideration for receiving a financial hardship
       benefit, the Participant will not be permitted to make further
       contributions to the Plan for the remainder of the Plan Year and the
       following Plan Year.

    6.0 DISTRIBUTIONS.

    6.1 FORMS OF BENEFITS. The Company shall pay benefits in the form associated
       with type of benefit elected by the Participant, and, to the extent a
       type of benefit may be distributed in various forms, the Company shall
       pay benefits in the form elected by the Participant. The forms of
       benefits associated with the types of benefits are the following:

       (A) Retirement Benefit, Termination of Service Benefit, Disability
           Benefit, and Death Benefit shall be paid in

            (i) one lump sum;

            (ii) 5 yearly installments;

           (iii) 10 yearly installments; or

            (iv) 15 yearly installments;

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       (B) In-Service Withdrawal shall be paid as provided in Section 5.5 above;

       (C) Unplanned In-Service Benefit shall be paid in one lump sum; and

       (D) Financial Hardship Benefit shall be paid in one lump sum.

    6.2 COMMENCEMENT OF PAYMENTS. The Company will pay, or begin to pay, the
       Types of Benefits under this Plan to the Participant in accordance with
       the following:

       (A) Retirement Benefit, Termination of Service Benefit, Disability
           Benefit and Death Benefit payments shall commence on the later of

            (i) The date specified in the Participant's initial election form or

            (ii) January 15th of the Plan Year immediately following the date on
                 which the Participant retires, terminates service, becomes
                 disabled, or dies;

       (B) In-Service Withdrawal payments shall commence on the date designated
           by the Participant on their written election pursuant to
           Section 2.4, provided that such payments are from Participant
           contributions that have been in such Participant's account for at
           least three years;

       (C) Unplanned In-Service Benefit payments shall commence no later than
           sixty-five (65) days after a written request for an Unplanned
           In-Service Benefit is received by the Plan Committee;

       (D) Financial Hardship Benefit payments shall commence no later than
           sixty-five (65) days after a request for a Financial Hardship Benefit
           is approved by the Plan Committee.

    7.0 AMENDMENTS, TERMINATION OF PLAN, CHANGE OF CONTROL.

    7.1 AMENDMENTS. The Company reserves the right to amend the Plan at any time
       by the Controller. The Controller will determine the effective date of
       any such amendment. The amendment may not deprive any Participant or
       Beneficiary of any portion of a benefit under the terms of this Plan at
       the time of the amendment.

    7.2 TERMINATION OF PLAN. The Company reserves the right to terminate the
       Plan at any time by the Controller. In the event of Plan termination, the
       Company will calculate the Retirement Benefit of each Participant and
       distribute such amounts to the Participant or Beneficiary in a lump sum
       within thirty (30) days of the Plan's termination.

    7.3 CHANGE IN CONTROL. In the event of a Change in Control, the Plan shall
       terminate and the provisions in Section 7.2 shall control.

    8.0 BENEFITS NOT FUNDED. Participants and Beneficiaries have the status of
       unsecured creditors of the Company, and the Plan constitutes a mere
       promise by the Company to make benefit payments in the future. A
       Participant's or Beneficiary's interest in the Plan is an unsecured claim
       against the general assets of the Company, and neither the Participant
       nor a Beneficiary has any right against the account until the Plan has
       distributed the benefit. All amounts credited

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       to an account are the general assets of the Company and may be disposed
       of or used by the Company in such manner as it determines.

       It is the intention of the parties that this Plan shall constitute an
       unfunded arrangement maintained for the purpose of providing deferred
       compensation for a select group of management or highly compensated
       employees for purposes of Title I of the Employee Retirement Income
       Security Act of 1974.

    9.0 MISCELLANEOUS.

    9.1 DESIGNATION OF BENEFICIARY. Each Participant shall designate, in
       writing, prior to the date they first become a Participant in the Plan,
       one or more beneficiaries to receive their benefits under the provisions
       of Section 5.4. The Participant shall file the written designation with
       the Plan Committee. The Participant may revoke a previous beneficiary
       designation by filing a new written beneficiary designation with the Plan
       Committee.

       In any event, if a Participant or Beneficiary who has designated another
       beneficiary is divorced, all beneficiary designation executed prior to
       the effective date of the dissolution of marriage (or other decree or
       order entered under applicable state law) are automatically revoked under
       the term of this Section 9.1. In such event, the Participant or
       Beneficiary may designate one or more Beneficiaries in accordance with
       the terms of this Section 9.1. If none is made following the effective
       date of the dissolution of the marriage, the individual's benefits shall
       pass under the laws of interstate succession and the terms of the next
       following paragraph.

       If a Participant fails to file a valid designation of beneficiary with
       the Plan Committee under the provisions of this Section 9.1, or if a
       designated beneficiary fails to survive or receive any or all payments
       due hereunder, then the death benefit payable under this Plan shall be
       payable to the Participant's (or the Beneficiary's) spouse; if no spouse
       survives, then the Participant's (or Beneficiary's) children, with equal
       shares among living children and with the living descendants of a
       deceased child receiving equal portions of the deceased child's share; in
       the absence of spouse or descendants, to the Participant's (or
       Beneficiary's) parents; and in the absence of spouse, descendants or
       parents, to the Participant's (Beneficiary's) brothers and sisters, with
       the living descendants of a deceased brother and those of a deceased
       sister receiving equal portions of the deceased brother's or sister's
       share; in the absence of any of the persons name herein, to the
       Participant's (or beneficiary's) estate.

       For purposes of this Section 9.1, the term "descendant" means all persons
       who are descended from the person referred to either by birth or to legal
       adoption by such person, and "child" or "children" includes adopted
       children.

    9.2 BENEFITS NOT ASSIGNABLE. The rights of each Participant are not subject
       in any manner or anticipation, alienation, sale, transfer, assignment,
       pledge, encumbrance, attachment, or garnishment by creditors of the
       Participant nor any Beneficiary. Neither the Participant nor Beneficiary
       may assign, transfer or pledge the benefits under this Plan. Any attempt
       to assign, transfer or pledge a Participant's benefits under this Plan is
       void.

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    9.3 BENEFIT. This Plan constitutes an agreement between the Company and each
       of the Participants which is binding upon and inures to the Company, its
       successors and assigns and upon the Participant and their heirs and legal
       representatives
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    9.4 HEADINGS. The headings of the Articles and Sections of this Plan are
       included for purposes of convenience only, and shall not affect the
       construction or interpretation of any of its provisions.

    9.5 NOTICES. All notices requests, demands, and other communication under
       this Plan shall be in writing and shall be deemed to have been duly given
       on the date of service if served personally on the party to whom notice
       is to be given, or on the third day after mailing if mailed to the party
       to whom notice is to be given, by first class mail, registered or
       certified (return receipt requested), postage prepaid, and properly
       addressed to the last known address to each party as set forth on the
       first page thereof. Any party may change its address for purposes of this
       Section by giving the other parties written notice of the new address in
       the manner set forth above.

    9.6 NO LOANS. The Plan does not permit any loans to be made to any
       Participant or Beneficiary.

    9.7 GENDER USAGE. The use of the masculine gender includes the feminine
       gender for all purposes of this Plan.

    9.8 EXPENSES. Costs of administration of the Plan shall be paid by the
       Company.

       The Company has adopted the Plan on December 15, 1998, effective
       January 1, 1999.

       This Amendment and Restatement is effective September 5, 2001.

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                                             IDEC PHARMACEUTICALS CORPORATION

                                             By:  /s/ Edward M. Rodriguez
                                                  ------------------------------------------
                                                  Edward M. Rodriguez
                                                  Vice President and Controller
</Table>