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                                                                 EXHIBIT 10.27


                        MILLENNIUM BIOTHERAPEUTICS, INC.

                           1997 EQUITY INCENTIVE PLAN


1. PURPOSE.

     The purpose of this plan (the "Plan") is to secure for Millennium
BioTherapeutics, Inc. (the "Company") and its shareholders the benefits arising
from capital stock ownership by employees and directors of, and consultants or
advisors to, the Company and its parent Millennium Pharmaceuticals, Inc., or any
successor entity thereto (the "Parent"), and subsidiary corporations who are
expected to contribute to the Company's future growth and success. Except where
the context otherwise requires, the term "Company" shall include the Parent and
all present and future subsidiaries of the Company or the Parent as defined in
Sections 424(e) and 424(f) of the Internal Revenue Code of 1986, as amended or
replaced from time to time (the "Code").

2. TYPE OF OPTIONS AND AWARDS; ADMINISTRATION.

     (a) TYPES OF OPTIONS AND AWARDS. Options granted pursuant to the Plan shall
be authorized by action of the Board of Directors of the Company (or a Committee
designated by the Board of Directors) and may be either incentive stock options
("Incentive Stock Options") meeting the requirements of Section 422 of the Code
or non-statutory options which are not intended to meet the requirements of
Section 422 of the Code. Awards granted pursuant to the Plan shall be authorized
by action of the Board of Directors of the Company (or a Committee designated by
the Board of Directors) and shall meet the requirements of Section 13 of the
Plan.

     (b) ADMINISTRATION. The Plan will be administered by the Board of Directors
of the Company, whose construction and interpretation of the terms and
provisions of the Plan shall be final and conclusive. The Board of Directors may
in its sole discretion (i) grant options to purchase shares of the Company's
Common Stock (as defined in Section 4 of the Plan), and issue shares upon
exercise of such options as provided in the Plan and (ii) make awards for the
purchase of shares of Common Stock pursuant to Section 13 of the Plan. The Board
shall have authority, subject to the express provisions of the Plan, to construe
the respective option agreements, awards and the Plan, to prescribe, amend and
rescind rules and regulations relating to the Plan, to determine the terms and
provisions of the respective option agreements and awards, which need not be
identical, and to make all other determinations in the judgment of the Board of
Directors necessary or desirable for the administration of the Plan. The Board
of Directors may correct any defect or supply any omission or reconcile any
inconsistency in the Plan or in any option agreement or award in the manner and
to the extent it shall deem expedient to carry the Plan into effect and it shall
be the sole and final judge of such expediency. No director or person acting
pursuant to authority delegated by the Board of Directors shall be liable for
any action or determination made in good faith. The Board of Directors may, to
the full extent permitted by or consistent with applicable laws or regulations
(including, without limitation, applicable state law), delegate any or all of
its powers under the Plan to a committee


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(the "Committee") appointed by the Board of Directors, and if the Committee is
so appointed all references to the Board of Directors in the Plan shall mean and
relate to such Committee to the extent authority is so delegated to such
Committee.

3. ELIGIBILITY.

     Options and awards may be granted or made to persons who are, at the time
of grant, employees and directors of, or consultants or advisors to, the
Company; PROVIDED, that the class of individuals to whom Incentive Stock Options
may be granted shall be limited to all employees of the Company. A person who
has been granted an option or award may, if he or she is otherwise eligible, be
granted additional options or awards if the Board of Directors shall so
determine. Subject to adjustment as provided in Section 16 below, the maximum
number of shares with respect to which options or restricted stock awards may be
granted to any person under the Plan shall not exceed 300,000 shares of Common
Stock during any calendar year during the term of the Plan. For the purpose of
calculating such maximum number, (a) an option or award shall continue to be
treated as outstanding notwithstanding its repricing, cancellation or expiration
and (b) the repricing of an outstanding option or award or the issuance of a new
option or award in substitution for a cancelled option or award shall be deemed
to constitute the grant of a new additional option or award, as the case may be,
separate from the original grant that is repriced or cancelled.

4. STOCK SUBJECT TO PLAN.

     Subject to adjustment as provided in Section 16 below, the total number of
shares which may be issued and sold under the Plan is 1,000,000 shares of Class
B Common Stock of the Company, $.001 par value per share ("Common Stock"). If an
option granted under the Plan shall expire or terminate for any reason without
having been exercised in full, the unpurchased shares subject to such option
shall again be available for subsequent option grants or awards under the Plan.

5. FORMS OF OPTION AGREEMENTS.

     As a condition to the grant of an option under the Plan, each recipient of
an option shall execute an option agreement in such form not inconsistent with
the Plan as may be approved by the Board of Directors. Such option agreements
may differ among recipients.


6. PURCHASE PRICE UPON EXERCISE OF OPTIONS.

     (a) GENERAL. The purchase price per share of Common Stock deliverable upon
the exercise of an option shall be determined by the Board of Directors,
PROVIDED, HOWEVER, that in the case of an Incentive Stock Option, the exercise
price shall not be less than 100% of the fair market value of such stock, as
determined by the Board of Directors, at the time of grant of such option, or
less than 110% of such fair market value in the case of options described in
Section 11(b).


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     (b) PAYMENT OF PURCHASE PRICE. Options granted under the Plan may provide
for the payment of the exercise price by delivery of cash or a check to the
order of the Company in an amount equal to the exercise price of such options,
or, to the extent provided in the applicable option agreement, (i) by delivery
to the Company of shares of Common Stock of the Company already owned by the
optionee having a fair market value equal in amount to the exercise price of the
options being exercised, (ii) by any other means (including without limitation
by delivery of a promissory note of the optionee payable on such terms as are
specified by the Board of Directors) which the Board of Directors determines are
consistent with the purpose of the Plan and with applicable laws and regulations
(including, without limitation, the provisions of Regulation T promulgated by
the Federal Reserve Board) or (iii) by any combination of such methods of
payment. The fair market value of any shares of the Company's Common Stock or
other non-cash consideration which may be delivered upon exercise of an option
shall be determined in such manner as may be prescribed by the Board of
Directors.

7. OPTION PERIOD.

     Each option and all rights thereunder shall expire on such date as shall be
set forth in the applicable option agreement, except that such date, in the case
of an Incentive Stock Option, shall in no case be later than ten years after the
date on which the option is granted.

8. EXERCISE OF OPTIONS.

     Each option granted under the Plan shall be exercisable either in full or
in installments at such time or times and during such period as shall be set
forth in the agreement evidencing such option, subject to the provisions of the
Plan.

9. NONTRANSFERABILITY OF OPTIONS.

     Incentive Stock Options shall not be assignable or transferable by the
person to whom it is granted, either voluntarily or by operation of law, except
by will or the laws of descent and distribution, and, during the life of the
optionee, shall be exercisable only by the optionee.

10. EFFECT OF TERMINATION OF EMPLOYMENT OR OTHER RELATIONSHIP.

     The Board of Directors shall determine the period of time during which an
optionee may exercise an option following (i) the termination of the optionee's
employment or other relationship with the Company or (ii) the death or
disability of the optionee. Such periods shall be set forth in the agreement
evidencing such option.

11. INCENTIVE STOCK OPTIONS.

     Options granted under the Plan which are intended to be Incentive Stock
Options shall be subject to the following additional terms and conditions:

     (a) EXPRESS DESIGNATION. All Incentive Stock Options granted under the Plan
shall, at the time of grant, be specifically designated as such in the option
agreement covering such Incentive Stock Options.


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     (b) 10% SHAREHOLDER. If any employee to whom an Incentive Stock Option is
to be granted under the Plan is, at the time of the grant of such option, the
owner of stock possessing more than 10% of the total combined voting power of
all classes of stock of the Company (after taking into account the attribution
of stock ownership rules of Section 424(d) of the Code), then the following
special provisions shall be applicable to the Incentive Stock Option granted to
such individual:

          (i) The purchase price per share of the Common Stock subject to such
     Incentive Stock Option shall not be less than 110% of the fair market value
     of one share of Common Stock at the time of grant; and

          (ii) The option exercise period shall not exceed five years from the
     date of grant.

     (c) DOLLAR LIMITATION. For so long as the Code shall so provide, options
granted to any employee under the Plan (and any other incentive stock option
plans of the Company) which are intended to constitute Incentive Stock Options
shall not constitute Incentive Stock Options to the extent that such options, in
the aggregate, become exercisable for the first time in any one calendar year
for shares of Common Stock with an aggregate fair market value (determined as of
the respective date or dates of grant) of more than $100,000.

     (d) TERMINATION OF EMPLOYMENT, DEATH OR DISABILITY. No Incentive Stock
Option may be exercised unless, at the time of such exercise, the optionee is,
and has been continuously since the date of grant of his or her option, employed
by the Company, except that:

          (i) an Incentive Stock Option may be exercised within the period of
     three months after the date the optionee ceases to be an employee of the
     Company (or within such lesser period as may be specified in the applicable
     option agreement), PROVIDED, that the agreement with respect to such option
     may designate a longer exercise period and that the exercise after such
     three-month period shall be treated as the exercise of a non-statutory
     option under the Plan;

          (ii) if the optionee dies while in the employ of the Company, or
     within three months after the optionee ceases to be such an employee, the
     Incentive Stock Option may be exercised, by the person to whom it is
     transferred by will or the laws of descent and distribution, within the
     period of one year after the date of death (or within such lesser period as
     may be specified in the applicable option agreement); and

          (iii) if the optionee becomes disabled (within the meaning of Section
     22(e)(3) of the Code or any successor provision thereto) while in the
     employ of the Company, the Incentive Stock Option may be exercised within
     the period of one year after the date the optionee ceases to be such an
     employee because of such disability (or within such lesser period as may be
     specified in the applicable option agreement).


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For all purposes of the Plan and any option or award granted hereunder,
"employment" shall be defined in accordance with the provisions of Section
1.421-7(h) of the Income Tax Regulations (or any successor regulations).
Notwithstanding the foregoing provisions, no stock option may be exercised after
its expiration date.

12. ADDITIONAL PROVISIONS.

     (a) ADDITIONAL OPTION PROVISIONS. The Board of Directors may, in its sole
discretion, include additional provisions in any option granted under the Plan,
including without limitation restrictions on transfer, repurchase rights,
commitments to pay cash bonuses, to make, arrange for or guaranty loans or to
transfer other property to optionees upon exercise of options, or such other
provisions as shall be determined by the Board of Directors; PROVIDED THAT such
additional provisions shall not be inconsistent with any other term or condition
of the Plan.

     (b) ACCELERATION, EXTENSION, ETC. The Board of Directors may, in its sole
discretion, (i) accelerate the date or dates on which all or any particular
option or options granted under the Plan may be exercised or (ii) extend the
dates during which all or any particular option or options granted under the
Plan may be exercised; provided, however, that no such extension shall be
permitted if it would cause the Plan to fail to comply with Section 422 of the
Code.

13. AWARDS.

     A restricted stock award (an "award") shall consist of the sale and
issuance by the Company of shares of Common Stock, and the purchase by the
recipient of such shares, subject to the terms, conditions and restrictions
described in the document evidencing the award and in this Section 13 and
elsewhere in the Plan.

     (a) EXECUTION OF RESTRICTED STOCK AWARD AGREEMENT. As a condition to an
award under the Plan, each recipient of an award shall execute an agreement in
such form, which may differ among recipients, as shall be specified by the Board
of Directors at the time of such award.

     (b) PRICE. The Board of Directors shall determine the price at which shares
of Common Stock shall be sold to recipients of awards under the Plan. The Board
of Directors may, in its discretion, issue shares pursuant to awards without the
payment of any cash purchase price by the recipients or issue shares pursuant to
awards at a purchase price below the then fair market value of the Common Stock.
If a purchase price is required to be paid, it shall be paid in cash or by check
payable to the order of the Company at the time that the award is accepted by
the recipient, or by such other means as may be approved by the Board of
Directors.

     (c) NUMBER OF SHARES. The award shall specify the number of shares of
Common Stock granted thereunder.

     (d) RESTRICTIONS ON TRANSFER. In addition to such other terms, conditions
and restrictions upon awards as shall be imposed by the Board of Directors, all
shares issued pursuant to an award shall be subject to the following
restrictions:


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          (1) All shares of Common Stock subject to an award (including any
     shares issued pursuant to paragraph (e) of this Section) shall be subject
     to certain restrictions on disposition and obligations of resale to the
     Company as provided in subparagraph (2) below for the period specified in
     the document evidencing the award, and shall not be sold, assigned,
     transferred, pledged, hypothecated or otherwise disposed of until such
     restrictions lapse. The period during which such restrictions are
     applicable is referred to as the "Restricted Period."

          (2) In the event that a recipient's employment with the Company (or
     consultancy or advisory relationship, as the case may be) is terminated
     within the Restricted Period, whether such termination is voluntary or
     involuntary, with or without cause, or because of the death or disability
     of the recipient, the Company shall have the right and option for a period
     of three months following such termination to buy for cash that number of
     the shares of Common Stock purchased under the award as to which the
     restrictions on transfer and the forfeiture provisions contained in the
     award have not then lapsed, at a price equal to the price per share
     originally paid by the recipient. If such termination occurs within the
     last three months of the applicable restrictions, the restrictions and
     repurchase rights of the Company shall continue to apply until the
     expiration of the Company's three month option period.

          (3) Notwithstanding subparagraphs (1) and (2) above, the Board of
     Directors may, in its discretion, either at the time that an award is made
     or at any time thereafter, waive its right to repurchase shares of Common
     Stock upon the occurrence of any of the events described in this paragraph
     (d) or remove or modify any part or all of the restrictions. In addition,
     the Board of Directors may, in its discretion, impose upon the recipient of
     an award at the time of such award such other restrictions on any shares of
     Common Stock issued pursuant to such award as the Board of Directors may
     deem advisable.

     (e) ADDITIONAL SHARES. Any shares received by a recipient of an award as a
stock dividend on, or as a result of stock splits, combinations, exchanges of
shares, reorganizations, mergers, consolidations or otherwise with respect to,
shares of Common Stock received pursuant to such award shall have the same
status and shall bear the same restrictions, all on a proportionate basis, as
the shares initially purchased pursuant to such award.

     (f) TRANSFERS IN BREACH OF AWARD. If any transfer of shares purchased
pursuant to an award is made or attempted contrary to the terms of the Plan and
of such award, the Board of Directors shall have the right to purchase for the
account of the Company those shares from the owner thereof or his or her
transferee at any time before or after the transfer at the price paid for such
shares by the person to whom they were awarded under the Plan. In addition to
any other legal or equitable remedies which it may have, the Company may enforce
its rights by specific performance to the extent permitted by law. The Company
may refuse for any purpose to recognize as a shareholder of the Company any
transferee who receives any shares contrary to the provisions of the Plan and
the applicable award or any recipient of an award who breaches his or her
obligation to resell shares as required by the provisions of the Plan and the
applicable


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award, and the Company may retain and/or recover all dividends on such shares
which were paid or payable subsequent to the date on which the prohibited
transfer or breach was made or attempted.

     (g) ADDITIONAL AWARD PROVISIONS. The Board of Directors may, in its sole
discretion, include additional provisions in any award granted under the Plan,
including without limitation commitments to pay cash bonuses, make, arrange for
or guarantee loans or transfer other property to recipients upon the grant of
awards, or such other provisions as shall be determined by the Board of
Directors.

14. GENERAL RESTRICTIONS.

     (a) INVESTMENT REPRESENTATIONS. The Company may require any person to whom
an option or award is granted, as a condition of exercising such option or
purchasing the shares subject to the award, to give written assurances in
substance and form satisfactory to the Company to the effect that such person is
acquiring the Common Stock subject to the option or award for his or her own
account for investment and not with any present intention of selling or
otherwise distributing the same, and to such other effects as the Company deems
necessary or appropriate in order to comply with federal and applicable state
securities laws.

     (b) COMPLIANCE WITH SECURITIES LAWS. Each option and award shall be subject
to the requirement that if, at any time, counsel to the Company shall determine
that the listing, registration or qualification of the shares subject to such
option or award upon any securities exchange or under any state or federal law,
or the consent or approval of any governmental or regulatory body, or that the
disclosure of non-public information or the satisfaction of any other condition
is necessary as a condition of, or in connection with, the issuance or purchase
of shares thereunder, such option or award may not be exercised, in whole or in
part, unless such listing, registration, qualification, consent or approval, or
satisfaction of such condition shall have been effected or obtained on
conditions acceptable to the Board of Directors. Nothing herein shall be deemed
to require the Company to apply for or to obtain such listing, registration or
qualification, or to satisfy such condition.

15. RIGHTS AS A SHAREHOLDER.

     The holder of an option or recipient of an award shall have no rights as a
shareholder with respect to any shares covered by the option or award
(including, without limitation, any rights to receive dividends or non-cash
distributions with respect to such shares) until the date of issue of a stock
certificate to him or her for such shares. No adjustment shall be made for
dividends or other rights for which the record date is prior to the date such
stock certificate is issued.

16. ADJUSTMENT PROVISIONS FOR RECAPITALIZATIONS AND RELATED TRANSACTIONS.

     (a) GENERAL. If, through or as a result of any merger, consolidation, sale
of all or substantially all of the assets of the Company, reorganization,
recapitalization, reclassification, stock dividend, stock split, reverse stock
split or other similar transaction, (i) the outstanding


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shares of Common Stock are increased or decreased or are exchanged for a
different number or kind of shares or other securities of the Company, or (ii)
additional shares or new or different shares or other securities of the Company
or other non-cash assets are distributed with respect to such shares of Common
Stock or other securities, an appropriate and proportionate adjustment shall be
made in (x) the maximum number and kind of shares reserved for issuance under
the Plan, (y) the number and kind of shares or other securities subject to then
outstanding options under the Plan, and (z) the price for each share subject to
any then outstanding options under the Plan or repurchase rights of the Company,
without changing the aggregate purchase price as to which such options remain
exercisable, provided that no adjustment shall be made pursuant to this Section
16 if such adjustment would cause the Plan to fail to comply with Section 422 of
the Code.

     (b) BOARD AUTHORITY TO MAKE ADJUSTMENTS. Any adjustments under this Section
16 will be made by the Board of Directors, whose determination as to what
adjustments, if any, will be made and the extent thereof will be final, binding
and conclusive. No fractional shares will be issued under the Plan on account of
any such adjustments.

17. MERGER, CONSOLIDATION, ASSET SALE, LIQUIDATION, ETC.

     (a) GENERAL. In the event of a consolidation or merger in which outstanding
shares of Common Stock are exchanged for securities, cash or other property of
any other corporation or business entity or in the event of a liquidation of the
Company or sale of all or substantially all of the assets of the Company, the
Board of Directors of the Company, or the board of directors of any corporation
assuming the obligations of the Company, may, in its discretion, take any one or
more of the following actions, as to outstanding options and awards: (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, (ii) upon written notice to the
optionees, provide that all unexercised options will terminate immediately prior
to the consummation of such transaction unless exercised by the optionee within
a specified period following the date of such notice, (iii) in the event of a
merger under the terms of which holders of the Common Stock of the Company will
receive upon consummation thereof a cash payment for each share surrendered in
the merger (the "Merger Price"), make or provide for a cash payment to the
optionees equal to the difference between (A) the Merger Price times the number
of shares of Common Stock subject to such outstanding options (to the extent
then exercisable at prices not in excess of the Merger Price) and (B) the
aggregate exercise price of all such outstanding options in exchange for the
termination of such options, and (iv) provide that all or any outstanding
options shall become exercisable in full, any restrictions on exercising
outstanding options issued pursuant to the Plan prior to any given date shall
terminate and any restrictions on and rights of the Company to repurchase shares
covered by outstanding awards issued pursuant to the Plan shall terminate.

     (b) SUBSTITUTE OPTIONS. The Company may grant options under the Plan in
substitution for options held by employees of another corporation who become
employees of the Company, or a subsidiary of the Company, as the result of a
merger or consolidation of the employing corporation with the Company or a
subsidiary of the Company, or as a result of the

<PAGE>


acquisition by the Company, or one of its subsidiaries, of property or stock of
the employing corporation. The Company may direct that substitute options be
granted on such terms and conditions as the Board of Directors considers
appropriate in the circumstances.

18. NO SPECIAL EMPLOYMENT RIGHTS.

     Nothing contained in the Plan or in any option or award shall confer upon
any recipient of an award or optionee any right with respect to the continuation
of his or her employment by the Company or interfere in any way with the right
of the Company at any time to terminate such employment or to increase or
decrease the compensation of the optionee.

19. OTHER EMPLOYEE BENEFITS.

     Except as to plans which by their terms include such amounts as
compensation, neither the amount of any compensation deemed to be received by an
employee as a result of the exercise of an option or the sale of shares received
upon such exercise nor the value of an award granted to an employee will
constitute compensation with respect to which any other employee benefits of
such employee are determined, including, without limitation, benefits under any
bonus, pension, profit-sharing, life insurance or salary continuation plan,
except as otherwise specifically determined by the Board of Directors.

20. AMENDMENT OF THE PLAN.

     (a) The Board of Directors may at any time, and from time to time, modify
or amend the Plan in any respect, except that if at any time the approval of the
shareholders of the Company is required as to such modification or amendment
under Section 422 of the Code or any successor provision with respect to
Incentive Stock Options, the Board of Directors may not effect such modification
or amendment without such approval.

     (b) The termination or any modification or amendment of the Plan shall not,
without the consent of an optionee or recipient of an award, affect his or her
rights under an option or award previously granted to him or her. With the
consent of the optionee or recipient of the award affected, the Board of
Directors may amend outstanding option agreements or awards in a manner not
inconsistent with the Plan. The Board of Directors shall have the right to amend
or modify the terms and provisions of the Plan and of any outstanding Incentive
Stock Options granted under the Plan to the extent necessary to qualify any or
all such options for such favorable federal income tax treatment (including
deferral of taxation upon exercise) as may be afforded incentive stock options
under Section 422 of the Code.

21. WITHHOLDING.

     (a) The Company shall have the right to deduct from payments of any kind
otherwise due to the optionee or recipient of an award any federal, state or
local taxes of any kind required by law to be withheld with respect to any
shares issued upon exercise of options under the Plan or the purchase of shares
subject to the award. Subject to the prior approval of the Company, which may be
withheld by the Company in its sole discretion, the optionee or recipient of an


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award may elect to satisfy such obligations, in whole or in part, (i) by causing
the Company to withhold shares of Common Stock otherwise issuable pursuant to
the exercise of an option or the purchase of shares subject to an award or (ii)
by delivering to the Company shares of Common Stock already owned by the
optionee or award recipient. The shares so delivered or withheld shall have a
fair market value equal to such withholding obligation. The fair market value of
the shares used to satisfy such withholding obligation shall be determined by
the Company as of the date that the amount of tax to be withheld is to be
determined. An optionee or award recipient who has made an election pursuant to
this Section 21(a) may only satisfy his or her withholding obligation with
shares of Common Stock which are not subject to any repurchase, forfeiture,
unfulfilled vesting or other similar requirements.

     (b) If the recipient of an award under the Plan elects, in accordance with
Section 83(b) of the Code, to recognize ordinary income in the year of
acquisition of any shares awarded under the Plan, the Company will require at
the time of such election an additional payment for withholding tax purposes
based on the difference, if any, between the purchase price of such shares and
the fair market value of such shares as of the date immediately preceding the
date of the award.

22. CANCELLATION AND NEW GRANT OF OPTIONS, ETC.

     The Board of Directors shall have the authority to effect, at any time and
from time to time, with the consent of the affected optionees, (i) the
cancellation of any or all outstanding options under the Plan and the grant in
substitution therefor of new options under the Plan covering the same or
different numbers of shares of Common Stock and having an option exercise price
per share which may be lower or higher than the exercise price per share of the
cancelled options or (ii) the amendment of the terms of any and all outstanding
options under the Plan to provide an option exercise price per share which is
higher or lower than the then-current exercise price per share of such
outstanding options.

23. EFFECTIVE DATE AND DURATION OF THE PLAN.

     (a) EFFECTIVE DATE. The Plan shall become effective when adopted by the
Board of Directors, but no Incentive Stock Option granted under the Plan shall
become exercisable unless and until the Plan shall have been approved by the
Company's shareholders. If such shareholder approval is not obtained within
twelve months after the date of the Board's adoption of the Plan, no options
previously granted under the Plan shall be deemed to be Incentive Stock Options
and no Incentive Stock Options shall be granted thereafter. Amendments to the
Plan not requiring shareholder approval shall become effective when adopted by
the Board of Directors; amendments requiring shareholder approval (as provided
in Section 20) shall become effective when adopted by the Board of Directors,
but no Incentive Stock Option issued after the date of such amendment shall
become exercisable (to the extent that such amendment to the Plan was required
to enable the Company to grant such Incentive Stock Option to a particular
optionee) unless and until such amendment shall have been approved by the
Company's shareholders. If such shareholder approval is not obtained within
twelve months of the Board's adoption of such amendment, any Incentive Stock
Options granted on or after the date of such amendment shall terminate to the
extent that such amendment to the Plan was required to enable the Company to


<PAGE>


grant such option to a particular optionee. Subject to this limitation, options
and awards may be granted under the Plan at any time after the effective date
and before the date fixed for termination of the Plan.

     (b) TERMINATION. Unless sooner terminated in accordance with Section 17,
the Plan shall terminate, with respect to Incentive Stock Options, upon the
earlier of (i) the close of business on the day next preceding the tenth
anniversary of the date of its adoption by the Board of Directors, or (ii) the
date on which all shares available for issuance under the Plan shall have been
issued pursuant to the exercise or cancellation of options or the final vesting
of awards granted under the Plan. Unless sooner terminated in accordance with
Section 17, the Plan shall terminate with respect to options which are not
Incentive Stock Options and awards on the date specified in (ii) above. If the
date of termination is determined under (i) above, then options outstanding on
such date shall continue to have force and effect in accordance with the
provisions of the instruments evidencing such options.

24. PROVISION FOR FOREIGN PARTICIPANTS.

     The Board of Directors may, without amending the Plan, modify awards or
options granted to participants who are foreign nationals or employed outside
the United States to recognize differences in laws, rules, regulations or
customs of such foreign jurisdictions with respect to tax, securities, currency,
employee benefit or other matters.


                                       Adopted by the Board of Directors and
                                       Stockholders on May 27, 1997




<PAGE>



                                  AMENDMENT TO
                           1997 EQUITY INCENTIVE PLAN
                                       OF
                        MILLENNIUM BIOTHERAPEUTICS, INC.



     The 1997 Equity Incentive Plan (the "Plan") of Millennium BioTherapeutics,
Inc. (the "Company") be and hereby is amended as follows:

     1. Section 1 of the Plan is deleted in its entirety and a new Section 1 is
inserted in lieu thereof which reads as follows:

          1. PURPOSE.

               The purpose of this plan (the "Plan") is to secure for Millennium
          BioTherapeutics, Inc. (the "Company") and its shareholders the
          benefits arising from capital stock ownership by employees and
          directors of, and consultants or advisors to, the Company and its
          parent Millennium Pharmaceuticals, Inc., or any successor entity
          thereto (the "Parent"), and all present and future subsidiary
          corporations of (a) the Parent, other than the Company ("Parent
          Subsidiaries"), and (b) the Company ("Company Subsidiaries"), in each
          case who are expected to contribute to the Company's future growth and
          success. Except where the context otherwise requires, the term
          "Company" shall include the Parent and all Parent Subsidiaries and
          Company Subsidiaries.

          2. Section 3 of the Plan is deleted in its entirety and a new Section
             3 is inserted in lieu thereof which reads as follows:

          3. ELIGIBILITY.

               Options and awards may be granted or made to persons who are, at
          the time of grant, employees and directors of, or consultants or
          advisors to, the Company, its Parent, Parent Subsidiaries or Company
          Subsidiaries; PROVIDED, that the class of individuals to whom
          Incentive Stock Options may be granted shall be limited to all
          employees of the Company, its Parent and Company Subsidiaries. A
          person who has been granted an option or award may, if he or she is
          otherwise eligible, be granted additional options or awards if the
          Board of Directors shall so determine. Subject to adjustment as
          provided in Section 16 below, the maximum number of shares with
          respect to which options or restricted stock awards may be granted to
          any person under the Plan shall not exceed 300,000 shares of Common
          Stock during any calendar year during the term of the Plan. For the
          purpose of calculating such maximum number, (a) an option or award
          shall continue to be treated as outstanding notwithstanding its
          repricing, cancellation or expiration and (b) the repricing of an
          outstanding option or award or the issuance of a new option or award
          in

<PAGE>




          substitution for a cancelled option or award shall be deemed to
          constitute the grant of a new additional option or award, as the case
          may be, separate from the original grant that is repriced or
          cancelled.



                                           Approved by the Board of Directors
                                           of the Company on November 21, 1997

                                           Approved by the Stockholders
                                           of the Company on April 30, 1998