Document:

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                                                                    Exhibit 10.4

                         VIRUS RESEARCH INSTITUTE, INC.

                           1992 Equity Incentive Plan
                     Amended and Restated as of May 10, 1996

      Section 1. Purpose. The purpose of the Virus Research Institute, Inc. 1992
Equity Incentive Plan, as amended and restated (the "Plan"), is to attract and
retain officers, employees, directors and consultants to provide an incentive
for them to assist the Company to achieve long-range performance goals and to
enable them to participate in the long-term growth of the Company.

      Section 2. Definitions.

      "Act" means the Securities Exchange Act of 1934, as amended.

      "Affiliate" means any business entity in which the Company owns directly
or indirectly 50% or more of the total combined voting power or has a
significant financial interest as determined by the Committee.

      "Award" means any Option or Restricted Stock awarded under the Plan.

      "Board" means the Board of Directors of the Company.

      "Change of Control" has the meaning set forth in Section 10.

      "Code" means the Internal Revenue Code of 1986, as amended from time to
time and any successor code and related rules, regulations and interpretations.

      "Committee" means the Committee of the Board referred to in Section 3.

      "Common Stock" or "Stock" means the Common Stock, $0.001 par value, of the
Company, subject to adjustments pursuant to Section 5(b).

      "Company" means Virus Research Institute, Inc.

      "Designated Beneficiary" means the beneficiary designated by a
Participant, in a manner determined by the Committee, to receive amounts due or
exercise rights of the Participant in the event of the Participant's death. In
the absence of an effective designation by a Participant, designated Beneficiary
shall mean the Participant's estate.

      "Disinterested Person" means an Independent Director who qualifies as a
"disinterested person" under Rule 16b-3(c)(2)(i) promulgated under the Act, or
any successor definition under said Rule.
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      "Fair Market Value" means (i) with respect to Common Stock, (x) if the
Common Stock is listed or admitted for trading on any national securities
exchange, the last sales price or the closing bid price if no sale occurred, of
Common Stock on the principal securities exchange on which such class of stock
is listed, (y) if the Common Stock is not listed or admitted for trading on any
such exchange, the last reported sales price of Common Stock on the Nasdaq Stock
Market, or any similar system of automatic quotation of securities prices then
in common use, if so quoted, or (z) if not so quoted as described in clause (y),
the mean between the high and the low asked quotations for the Common Stock as
reported by the National Quotation Bureau Incorporated if at least two
securities dealers have inserted both bid and asked quotations for such class of
stock on at least five of the ten trading days preceding the day in question; or
(ii) with respect to any other property, the fair market value of such property
as determined by the Committee in good faith or in the manner established by the
Committee from time to time. Notwithstanding the foregoing, the Fair Market
Value of the Common Stock on the effective date of the Company's initial public
offering shall be the offering price to the public of the Common Stock on such
date.

      "Incentive Stock Option" means an option to purchase shares of Common
Stock awarded to a Participant under Section 6 which is intended to meet the
requirements of Section 422 of the Code or any successor provision.

      "Independent Director" means a member of the Board who is not also an
employee of the Company.

      "Nonstatutory Stock Option" means an option to purchase shares of Common
Stock awarded to a Participant under Sections 6 or 7 which is not intended to be
an Incentive Stock Option.

      "Option" means an Incentive Stock Option or a Nonstatutory Stock Option.

      "Participant" means a person selected by the Committee to receive an Award
under the Plan.

      "Restricted Period" means the period of time selected by the Committee
during which an award of Restricted Stock may be forfeited to the Company.
      "Restricted Stock" means shares of Common Stock subject to forfeiture
awarded to a Participant under Section 8.

      Section 3. Administration.

            (a) Committee. The Plan shall be administered by a committee of not
less than two Independent Directors as appointed by the Board from time to time
(the "Committee"). Each member of the Committee shall be a Disinterested Person.
On and after the date the Company becomes subject to Section 162(m) of the Code,
each member of the Committee shall also be an "outside director" within the
meaning of Section 162(m) of the Code and the regulations promulgated
thereunder.

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            (b) Powers of Committee. The Committee shall have the power and
authority to grant Awards consistent with the terms of the Plan, including the
power and authority:

            (i) to select the officers, employees and consultants of the Company
      to whom Awards may from time to time be granted;

            (ii) to determine the time or times of grant, and the extent, if
      any, of Incentive Stock Options, Nonstatutory Stock Options and Restricted
      Stock Awards or any combination of the foregoing, granted to any one or
      more Participants;

            (iii) to determine the number of shares of Common Stock to be
      covered by any Award;

            (iv) to determine and modify from time to time the terms and
      conditions, including restrictions, not inconsistent with the terms of the
      Plan, of any Award, which terms and conditions may differ among individual
      Awards and Participants, and to approve the form of written instruments
      evidencing the Awards;

            (v) to accelerate at any time the exercisability or vesting of all
      or any portion of any Award and/or include provisions in Awards providing
      for such acceleration;

            (vi) subject to the provisions of Section 6(c), to extend at any
      time the period in which Options may be exercised;

            (vii) to determine at any time whether, to what extent, and under
      what circumstances Common Stock and other amounts payable with respect to
      an Award shall be deferred either automatically or at the election of the
      Participant and whether and to what extent the Company shall pay or credit
      amounts constituting interest (at rates determined by the Committee) or
      dividends or deemed dividends on such deferrals; and

            (viii) at any time to adopt, alter and repeal such rules, guidelines
      and practices for administration of the Plan and for its own acts and
      proceedings as it shall deem advisable; to interpret the terms and
      provisions of the Plan and any Award (including related written
      instruments); to make all determinations it deems advisable for the
      administration of the Plan; to decide all disputes arising in connection
      with the Plan; and to otherwise supervise the administration of the Plan.

       All decisions and interpretations of the Committee shall be binding on
all persons, including the Company and the Participants.

            (c) Delegation of Authority to Grant Awards. The Committee, in its
discretion, may delegate to the Chief Executive Officer or Chief Financial
Officer of the Company all or part of the Committee's authority and duties with
respect to Awards, including the granting thereof, to individuals who are not
subject to the reporting and other provisions of Section 16 of the Act. The
Committee may revoke or amend the terms of a delegation at any time but

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such action shall not invalidate any prior actions of the Committee's delegate
or delegates that were consistent with the terms of the Plan.

      Section 4. Eligibility. All full and part-time officers and employees, and
in the case of Awards other than Incentive Stock Options, consultants of the
Company or any Affiliate capable of contributing significantly to the successful
performance of the Company, other than a person who has irrevocably elected not
to be eligible, are eligible to be Participants in the Plan. Independent
Directors are also eligible to participate in the Plan but only to the extent
provided in Section 7 below.

      Section 5. Stock Available for Awards.

            (a) Subject to adjustment under subsection (b), Awards may be made
under the Plan for up to 1,751,176 shares of Common Stock. If any Award in
respect of shares of Common Stock expires or is terminated unexercised or is
forfeited for any reason or settled in a manner that results in fewer shares
outstanding than were initially awarded, including, without limitation the
surrender of shares in payment for the Award or any tax obligation thereon, the
shares subject to such Award or so surrendered, as the case may be, to the
extent of such expiration, termination, forfeiture or decrease, shall again be
available for award under the Plan, subject, however, in the case of Incentive
Stock Options, to any limitation required under the Code. Shares issued under
the Plan may consist in whole or in part of authorized but unissued shares or
treasury shares. Subject to such overall limitation, shares of Common Stock may
be issued up to such maximum number pursuant to any type or types of Award;
provided, however, that on and after the date the Company is subject to Section
162(m) of the Code, Options with respect to no more than 250,000 shares of
Common Stock may be granted to any one individual Participant during any fiscal
year period.

            (b) If the Company effects a stock split, consolidation of shares or
other recapitalization of its stock, the payment of a stock dividend, or any
other increase or reduction in the number of shares of Common Stock outstanding
without receiving compensation therefor in money, services or property, then at
the discretion of the Board (i) the number, class, and price of shares of Common
Stock subject to outstanding Options hereunder shall be appropriately adjusted
by the Board in such a manner as to entitle each Optionee to receive upon
exercise of an Option in full, for the same aggregate consideration, that number
and class of shares which the Optionee would have received as a result of the
event requiring the adjustment had the Optionee exercised the Option in full
immediately prior to such event; and (ii) the number and class of shares
reserved for issuance under the Plan shall be appropriately adjusted by the
Board by substituting that number and class of shares of stock which
stockholders of the Company would have received as a result of such event if
they held all of the reserved shares immediately prior to such event; provided,
however, that outstanding Options and Options to be issued under the Plan shall
not be issued or exercisable for fractional shares, and the Board may determine
in its discretion to adjust outstanding Options or shares reserved under the
Plan to the nearest whole number of shares, or it may require payment of cash to
an Optionee who exercises an Option for a fractional share in an amount
reflecting the fair value of the fractional share as determined by the Board.

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      Section 6. Stock Options Granted to Officers. Employees and Consultants.

            (a) Subject to the provisions of the Plan, the Committee may award
Incentive Stock Options and Nonstatutory Stock Options and determine the number
of shares to be covered by each Option, the option price therefor and the
conditions and limitations applicable to the exercise of the Option. The terms
and conditions of Incentive Stock Options shall be subject to and comply with
Section 422 of the Code, or any successor provision, and any regulations
thereunder and to the extent that any Option does not qualify as an Incentive
Stock Option, it shall be deemed a Nonstatutory Stock Option.

            (b) The Committee shall establish the option price at the time each
Option is awarded, which price shall not be less than 100% of the Fair Market
Value of the Common Stock on the date of award; provided, however, if an officer
or employee owns or is deemed to own (by reason of the attribution rules
applicable under Section 424(d) of the Code) more than 10% of the combined
voting power of all classes of stock of the Company or any Affiliate and an
Incentive Stock Option is granted to such officer or employee, the option price
of such Incentive Stock Option shall be not less than 110% of the Fair Market
Value on the grant date.

            (c) The term of each Option shall be fixed by the Committee, but no
Incentive Stock Option shall be exercisable more than ten years after the date
the option is granted. If an officer or employee owns or is deemed to own (by
reason of the attribution rules of Section 424(d) of the Code) more than 10% of
the combined voting power of all classes of stock of the Company or any
Affiliate and an Incentive Stock Option is granted to such officer or employee,
the term of such option shall be no more than five years from the date of grant.

            (d) Each Option shall be exercisable at such times and subject to
such terms and conditions as the Committee may specify in the applicable Award
or thereafter. The Committee may impose such conditions with respect to the
exercise of Options, including conditions relating to applicable federal or
state securities laws, as it considers necessary or advisable. The Committee may
at any time accelerate the exercisability of all or any portion of any Option.

            (e) Options may be exercised in whole or in part, by giving written
notice of exercise to the Company, specifying the number of shares to be
purchased. Payment of the purchase price may be made by one or more of the
following methods:

                  (i)   In cash, by certified, bank or personal check or other
      instrument acceptable to the Committee;

                  (ii) In the form of shares of Common Stock that are not then
      subject to restrictions under any Company plan and, unless otherwise
      permitted by the Committee, that have been held by the optionee for at
      least six months. Such surrendered shares shall be valued at Fair Market
      Value on the exercise date;

                  (iii) By the optionee delivering to the Company a properly
      executed exercise notice together with irrevocable instructions to a
      broker to promptly deliver to the Company cash or a check payable and
      acceptable to the Company to pay the

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      purchase price; provided that in the event the optionee chooses to pay the
      purchase price as so provided, the optionee and the broker shall comply
      with such procedures and enter into such agreements of indemnity and other
      agreements as the Committee shall prescribe as a condition of such payment
      procedure;

                  (iv) by any other means which the Board determines are
      consistent with the purpose of the Plan and with applicable laws and
      regulations including, without limitation, the provisions of Rule 16b-3
      and Regulation T promulgated by the Federal Reserve Board; or

                  (v) by any combination of such methods of payment.

      Payment instruments will be received subject to collection. The delivery
of certificates representing the shares of Common Stock to be purchased pursuant
to the exercise of an Option will be contingent upon receipt from the optionee
(or a purchaser acting in his or her stead in accordance with the provisions of
the Option) by the Company of the full purchase price for such shares and the
fulfillment of any other requirements contained in the Option or applicable
provisions of laws.

            (f) To the extent required for "incentive stock option" treatment
under Section 422 of the Code, the aggregate Fair Market Value (determined as of
the time of grant) of the shares of Common Stock with respect to which Incentive
Stock Options granted under this Plan and any other plan of the Company or its
parent and subsidiary corporations become exercisable for the first time by an
optionee during any calendar year shall not exceed $100,000. To the extent that
any Option exceeds this limit, it shall constitute a Nonstatutory Stock Option.

      Section 7. Stock Options Granted to Independent Directors.

            (a) Automatic Grant of Options.

                  (i) Each Independent Director who is serving as a Director on
      the effective date of the Company's initial public offering shall be
      granted on such effective date a Nonstatutory Stock Option to acquire
      10,000 shares of Common Stock.

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                  (ii) Each Independent Director who is first elected to serve
      as a Director after the effective date of the Company's initial public
      offering shall be granted, on the day of his or her election, a
      Nonstatutory Stock Option to acquire 10,000 shares of Common Stock (an
      "Initial Director Option").

                  (iii) After each annual meeting of stockholders of the
      Company, beginning with the Company's 1998 annual meeting, each
      Independent Director who has not received an Initial Director Option
      during the preceding year and who is serving as Director of the Company on
      the first business day following such annual meeting of stockholders shall
      automatically be granted on such day a Nonstatutory Stock Option to
      acquire 2,000 shares of Common Stock.

                  (iv) The exercise price per share for the Common Stock covered
      by an Option granted under this Section 7 shall be equal to the Fair
      Market Value of the Common Stock on the date the Option is granted.

            (b) Exercise; Termination.

                  (i) Except as provided in Section 10, an Option granted to an
      Independent Director under Section 7 shall be exercisable in four equal
      annual installments commencing on the date of grant. An Option issued
      under this Section 7 shall not be exercisable after the expiration of ten
      years from the date of grant.

                  (ii) If an Independent Director ceases to be a Director for
      any reason, an Option granted under this Section 7 to such Independent
      Director shall terminate immediately with respect to all shares of Common
      Stock for which it is not then exercisable. With respect to the remaining
      shares, such Option shall terminate 90 days after the date the Independent
      Director ceases to be a Director or at the expiration of the stated term
      of the Option, if earlier; provided, however, that if the Independent
      Director dies while a Director or within such 90-day period after ceasing
      to be a Director, such Option may be exercised for such remaining shares
      by the personal representative or legatee of the optionee for a period of
      six months from the date of death or until the expiration of the stated
      term of the Option, if earlier.

                  (iii) Options granted under this Section 7 may be exercised
      only by written notice to the Company specifying the number of shares to
      be purchased. Payment of the full purchase price of the shares to be
      purchased may be made by one or more of the methods specified in Section
      6(e). An optionee shall have the rights of a stockholder only as to shares
      acquired upon the exercise of a Option and not as to unexercised Options.

            (c) Limited to Independent Directors. The provisions of this Section
7 shall apply only to Options granted or to be granted to Independent Directors,
and shall not be deemed to modify, limit or otherwise apply to any other
provision of this Plan or to any Option issued under this Plan to a Participant
who is not an Independent Director of the Company. To the extent inconsistent
with the provisions of any other Section of this Plan, the provisions of this
Section 7 shall govern the rights and obligations of the Company and Independent

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Directors respecting Options granted or to be granted to Independent Directors.
The provisions of this Section 7 which affect the price, date of exercisability,
option period or amount of shares of Common Stock under an Option shall not be
amended more than once in any six-month period, other than to conform with
changes in the Code or ERISA.

      Section 8. Restricted Stock.

            (a) Subject to the provisions of the Plan, the Committee may award
shares of Restricted Stock and determine the duration of the Restricted Period
during which, and the conditions under which, the shares may be forfeited to the
Company and the other terms and conditions of such Awards. Shares of Restricted
Stock shall be issued at par value or for such other consideration as
established by the Committee.

            (b) Shares of Restricted Stock may not be sold, assigned,
transferred, pledged or otherwise encumbered, except as permitted by the
Committee, during the Restricted Period. Shares of Restricted Stock shall be
evidenced in such manner as the Committee may determine. Any certificates issued
in respect of shares of Restricted Stock shall be registered in the name of the
Participant and unless otherwise determined by the Committee, deposited by the
Participant, together with a stock power endorsed in blank, with the Company. At
the expiration of the Restricted Period, the Company shall deliver such
certificates to the Participant or if the Participant has died, to the
Participant's Designated Beneficiary.

      Section 9. General Provisions Applicable to Awards.

            (a) Documentation. Each Award under the Plan shall be evidenced in
writing delivered to the Participant specifying the terms and conditions thereof
and containing such other terms and conditions not inconsistent with the
provisions of the Plan as the Committee considers necessary or advisable to
achieve the purposes of the Plan or comply with applicable tax and regulatory
laws and accounting principles.

            (b) Committee Discretion. Each type of Award may be made alone, in
addition to or in relation to any other type of Award. The terms of each type of
Award need not be identical, and the Committee need not treat Participants
uniformly. Except as otherwise provided by the Plan or a particular Award, any
determination with respect to an Award may be made by the Committee at the time
of award or at any time thereafter.

            (c) Termination of Employment. Unless otherwise provided in the
option agreement or determined by the Committee, upon an optionee's termination
of employment (or other business relationship) with the Company, the optionee's
rights in his or her Options, (i) to the extent not exercisable at the time of
termination, shall automatically expire and (ii) to the extent exercisable at
the time of termination, shall expire 90 days after such termination of
employment or at the expiration of the stated term of the Option, if earlier;
provided, however, that if an optionee's employment was terminated by reason of
death, his or her Options, to the extent exercisable, may be exercised by the
personal representative or legatee of the optionee for a period of six months
from the date of death or until expiration of the stated term of the Option, if
earlier.

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            (d) Withholding.

                  (i) The Participant shall pay to the Company, or make
provision satisfactory to the Committee for payment of any taxes required by law
to be withheld in respect of Awards under the Plan no later than the date of the
event creating the tax liability. The Company and its Affiliates may, to the
extent permitted by law, deduct any such tax obligations from any payment of any
kind otherwise due to the Participant.

                  (ii) In the Committee's discretion, such tax obligations may
be paid in whole or in part in shares of Common Stock. A Participant may elect
to have such tax withholding obligation satisfied, in whole or in part, by (i)
authorizing the Company to withhold from shares of Common Stock to be issued
pursuant to any Award a number of shares with an aggregate Fair Market Value (as
of the date the withholding is effected) that would satisfy the withholding
amount due, or (ii) transferring to the Company shares of Common Stock owned by
the Participant with an aggregate Fair Market Value (as of the date the
withholding is effected) that would satisfy the withholding amount due. With
respect to any Participant who is subject to Section 16 of the Act, the
following additional restrictions shall apply:

                  (A) the election to satisfy tax withholding obligations
      relating to an Award in the manner permitted by this Section 9(d)(ii)
      shall be made either (x) during the period beginning on the third business
      day following the date of release of quarterly or annual summary
      statements of sales and earnings of the Company and ending on the twelfth
      business day following such date, or (y) at least six months prior to the
      date as of which the receipt of such an Award first becomes a taxable
      event for Federal income tax purposes;

                  (B) such election shall be irrevocable;

                  (C) such election shall be subject to the consent or
      disapproval of the Committee; and

                  (D) the Common Stock withheld to satisfy tax withholding must
      pertain to an Award which has been held by the Participant for at least
      six months from the date of grant of the Award.

Notwithstanding the foregoing, the first sentence of Section 9(d)(ii)(A)(x)
shall not be applicable until the Company has been subject to the reporting
requirements of Section 13(a) of the Act for at least a year prior to the
election and has filed all reports and statements required to be filed pursuant
to that Section for that year.

            (e) Foreign Nationals. Awards may be made to Participants who are
foreign nationals or employed outside the United States on such terms and
conditions different from those specified in the Plan as the Committee considers
necessary or advisable to achieve the purposes of the Plan or comply with
applicable laws.

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            (f) Amendment of Award. The Committee may amend, modify or terminate
any outstanding Award, including substituting therefor another Award of the same
or a different type, changing the date of exercise or realization and converting
an Incentive Stock Option to a Nonstatutory Stock Option, provided that the
Participant's consent to such action shall be required unless the Committee
determines that the action, taking into account any related action, would not
materially and adversely affect the Participant.

            (g) Non-transferability of Awards. No Option shall be transferable
by the optionee otherwise than by will or by the laws of descent and
distribution and all Options shall be exercisable, during the optionee's
lifetime, only by the optionee. Restricted Stock may not be sold, assigned,
transferred, pledged or otherwise encumbered or disposed of except as
specifically provided herein or in the written instrument evidencing the Award.

      Section 10. Change of Control Provisions.

            (a) "Change of Control" shall mean the occurrence of any one of the
following events:

                  (i) any "person," as such term is used in Sections 13(d) and
      14(d) of the Act (other than the Company, any of its subsidiaries, or any
      trustee, fiduciary or other person or entity holding securities under any
      employee benefit plan or trust of the Company or any of its subsidiaries),
      together with all "affiliates" and "associates" (as such terms are defined
      in Rule 12b-2 under the Act) of such person, shall become the "beneficial
      owner" (as such term is defined in Rule 13d-3 under the Act), directly or
      indirectly, of securities of the Company representing 25% or more of the
      combined voting power of the Company's then outstanding securities having
      the right to vote in an election of the Company's Board of Directors
      ("Voting Securities"); provided, however, that for purposes of this clause
      (i) a "Change of Control" shall not be deemed to have occurred (A) solely
      as a result of a person who is party to the Company's Second Amended and
      Restated Stockholders Agreement, dated as of April 1994 and amended from
      time to time thereafter, and who is deemed to beneficially own at the
      close of business on the effective date of the Company's initial public
      offering 25% or more of the combined voting power of all then outstanding
      Voting Securities; (B) as the result of an acquisition of securities
      directly from the Company; or (C) as the result of an acquisition of
      securities by the Company which, by reducing the number of shares of
      Common Stock or other Voting Securities outstanding, increases the
      proportionate voting power represented by the Voting Securities
      beneficially owned by any person to 25% or more of the combined voting
      power of all then outstanding Voting Securities; provided further however,
      that if any person referred to in clause (A), (B) or (C) of this sentence
      shall thereafter become the beneficial owner of any additional shares of
      Voting Securities (other than pursuant to clauses (B) or (C) or a stock
      split, stock dividend, or similar transaction), then a "Change of Control"
      shall be deemed to have occurred for purposes of this clause (i);

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                  (ii) persons who, as of the effective date of the Company's
      initial public offering, constitute the Company's Board of Directors (the
      "Incumbent Directors") cease for any reason, including, without
      limitation, as a result of a tender offer, proxy contest, merger or
      similar transaction, to constitute at least a majority of the Board,
      provided that any person becoming a director of the Company subsequent to
      such effective date whose election or nomination for election was approved
      by a vote of at least a majority of the Incumbent Directors shall, for
      purposes of this Plan, be considered an Incumbent Director;

                  (iii) the stockholders of the Company shall approve (A) any
      consolidation or merger of the Company or any of its subsidiaries where
      the stockholders of the Company, immediately prior to the consolidation or
      merger, would not, immediately after the consolidation or merger,
      beneficially own (as such term is defined in Rule 1 3d-3 under the Act),
      directly or indirectly, shares representing in the aggregate 70% or more
      of the voting shares of the corporation issuing cash or securities in the
      consolidation or merger (or of its ultimate parent corporation, if any),
      (B) any sale, lease, exchange or other transfer (in one transaction or a
      series of transactions contemplated or arranged by any party as a single
      plan) of all or substantially all of the assets of the Company or (C) any
      plan or proposal for the liquidation or dissolution of the Company; or

                  (iv) when any "person" (as defined in (i) above) commences a
      tender offer for the outstanding shares of Common Stock of the Company.

            (b) Upon the occurrence of a Change of Control, (i) each outstanding
Option shall automatically become fully exercisable notwithstanding any
provision to the contrary herein and (ii) each Restricted Stock Award shall be
subject to such terms, if any, with respect to a Change of Control as have been
provided by the Committee in connection with such Award.

            (c) In the event of a Change of Control by reason of Section 1
0(a)(iii) above, the Board shall, in its discretion, take one or more of the
following actions with regard to outstanding Options: (i) provide that such
Options shall be assumed, or equivalent options shall be substituted, by the
acquiring or succeeding corporation (or an affiliate thereof) (provided that any
such options substituted for Incentive Stock Options shall meet the requirements
of Section 424(a) of the Code), such that the Options (or equivalent substituted
options) shall thereafter entitle the holder to receive upon exercise thereof
the aggregate number and kind of securities and property as such holder would
have been entitled to receive upon consummation of such transaction had he or
she exercised the Option immediately prior to effectiveness of the transaction;
(ii) upon prior written notice to the optionees, provide that all unexercised
Options will terminate immediately prior to the consummation of such transaction
unless any such Options are exercised by the optionee within a specified period
following the date of such notice and prior to the consummation of the
transaction; and/or (iii) make or provide for a cash payment to the optionees
equal to the difference between (A) the value (as determined by the Board of
Directors) of the consideration payable per share of Common Stock pursuant to
the transaction (the "Transaction Price") times the number of shares of Common
Stock subject to such outstanding Options (to the extent the exercise prices of
such Options are not in excess

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of the Transaction Price) and (B) the aggregate exercise price of all such
outstanding Options in exchange for the termination of all outstanding Options.

      Section 11. Miscellaneous.

            (a) No Right To Employment. No person shall have any claim or right
to be granted an Award, and the grant of an Award shall not be construed as
giving a Participant the right to continued employment. The Company expressly
reserves the right at any time to dismiss a Participant free from any liability
or claim under the Plan, except as expressly provided in the applicable Award.

            (b) No Rights As Stockholder. Subject to the provisions of the
applicable Award, no Participant or Designated Beneficiary shall have any rights
as a stockholder with respect to any shares of Common Stock to be distributed
under the Plan until he or she becomes the holder thereof. A Participant to whom
Common Stock is awarded shall be considered the holder of the Common Stock at
the time of the Award except as otherwise provided in the applicable Award.

            (c) Effective Date. Subject to the approval of the stockholders of
the Company, the Plan became effective on October 19, 1992 and the restatement
shall become effective on May 10, 1996.

            (d) Amendment of Plan. The Board may amend, suspend or terminate the
Plan or any portion thereof at any time; provided, however, that if and to the
extent determined by the Committee to be required by the Act to ensure that
Awards granted under the Plan are exempt under Rule 16b-3 promulgated under the
Act, or that Incentive Stock Options granted under the Plan are qualified under
Section 422 of the Code, Plan amendments shall be subject to approval by the
Company stockholders.

            (e) Governing Law. The provisions of the Plan shall be governed by
and interpreted in accordance with the laws of Delaware.

                                       12<PAGE>
                                                                    Exhibit 10.5

                              T CELL SCIENCES, INC.
                                PERFORMANCE PLAN

PURPOSE

      T Cell Sciences wishes to recognize the collective efforts of its
permanent employees by awarding them with additional compensation upon the
achievement of performance goals. The additional compensation will be determined
at the end of each fiscal year based on the employee's salary grade level and
the percentage of performance goals met during that fiscal year. The payout of
this additional compensation will be determined and allocated in accordance with
the Performance Plan, summarized below.

PERFORMANCE PLAN DESCRIPTION

(1) ELIGIBILITY & PARTICIPATION

      All permanent employees (full and part time) of T Cell Sciences who have
had permanent employment status for at least the last six months of a fiscal
year are eligible for a Performance Plan payout for that fiscal year. The payout
will a pro-rata amount based on the actual versus annualized permanent
employment base pay for the fiscal year.

      The Performance Plan payout will be a percentage of the employee's base
pay received during the fiscal year (excluding any overtime pay or other special
compensation) up to a set participation target for each salary ~r4de, as
established from time to time by the Compensation Committee of the Board of
Directors. The participation target for any individual employee may be set at a
lower level in the discretion of the Chief Executive Officer or at a higher
level with the approval of the Compensation Committee, from the participation
targets then in effect for the employee's salary grade.

      In the event an employee is promoted during a fiscal year into a salary
grade level with a higher participation target, the payout will be calculated
pro rata under the old and new targets based on the percentage of time the
employee has been employed in each salary grade level.

      Performance Plan payouts will normally be made after the end of each
fiscal year when a determination is made of the percentage of payout due to all
employees (see "Payout Determination" below). Payouts will be made only to
employees who have a permanent employment status with the Company at the time of
the payout, unless other arrangements have been approved in advance by the Chief
Executive Officer for employees eligible for participation of targets of 10% or
less or by the Compensation Committee for employees eligible for higher targets.

(2) PAYOUT DETERMINATION

      The Performance Plan payouts are determined by the achievement of
performance goals. In conjunction with the Company's budget process each fiscal
year, the performance goals for each fiscal year are proposed by management,
approved by the Compensation Committee and ratified by the Board of Directors.
The goals for any fiscal year may be set in whole or part on company-wide,
departmental and/or individual performance. The relative weight of each goal may
vary for different departments or individuals, with the weight to be approved
when the goals are approved.

<PAGE>

      At the end of each fiscal year, management of the Company will review with
the Compensation Committee the performance against each goal set for that fiscal
year. The Compensation Committee will determine the percentage of goals achieved
which will be the percentage to be applied against each employee's applicable
participation target. The percentage approved by the Compensation Committee will
be ratified by the Board of Directors.

      The approved participation target percentage will then be used to
calculate each employee's payout. The Performance Plan payouts are to be paid in
cash after any required deductions or withholdings.

(3) EFFECTIVE DATE AND AMENDMENTS

      The Performance Plan supersedes the Company's Management Incentive Plan
and is effective as of May 1, 1992, with the first payout to be made by December
31, 1992 for the eight month stub fiscal year. The Performance Plan may be
amended, suspended or terminated at any time at the discretion of the
Compensation Committee.

(4) NO CONTRACT OF EMPLOYMENT

      The Performance Plan shall not be considered to create any contract of
employment or any right of continued services between the Company and any
employee.

<PAGE>

                              T CELL SCIENCES INC.
                                PERFORMANCE PLAN

      Effective as of May 1, 1992, and until amended in writing by the
Compensation Committee, the participation targets for each salary grade will be
as set forth below:

             2 % - all non-exempt grades & exempt salary grades 1-5
             5 % - exempt salary grade 6
             10% - exempt salary grade 7-8
             15% - exempt salary grades 9-10, non-executive officers
             20% - executive officers

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