BIOGEN, INC.
                      1985 NON-QUALIFIED STOCK OPTION PLAN
                 (AS AMENDED THROUGH JUNE 20, 1998 AND RESTATED)


I.       PURPOSE OF THE PLAN

         The Plan is intended to  encourage  ownership of shares of Common Stock
of the  Company  by certain  employees  and  Directors  of the  Company  and its
Affiliates  and to  provide  an  additional  incentive  to those  employees  and
Directors to promote the success of the Company and its Affiliates.

II.      DEFINITIONS

     1. "Company" means Biogen, Inc., a Massachusetts corporation.

     2.  "Affiliate"  means a  corporation  in respect of which the Company owns
directly or indirectly  fifty percent (50%) or more of the voting shares thereof
or which is otherwise controlled by the Company.

     3. "Committee" means the Stock and Option Plan Administration Committee of
the Board of Directors of the Company.

     4. "Option" means a stock option granted under this Plan.

III. SHARES SUBJECT TO THE PLAN

     The aggregate number of shares as to which Options may be granted from time
to time shall be  20,454,000  of the shares of Common  Stock of the Company (par
value $.01);  provided,  however that such aggregate  number shall be reduced by
the  number of shares  which has been sold  under,  or may be sold  pursuant  to
options  granted from time to time under,  the Company's  1982  Incentive  Stock
Option Plan (the "ISO Plan"),  to the same extent as if such sales had been made
or options granted pursuant to this Plan.

     If any  option  granted  under  this Plan or the ISO Plan  ceases to be
"outstanding", in whole or in part, other than by reason of the exercise of such
option,  the shares which were subject to such option shall be available for the
granting of other Options.  Any option shall be treated as  "outstanding"  until
such option is exercised in full,  terminates  under the provisions of this Plan
or the ISO Plan, as the case may be, or expires by reason of lapse of time.

     The aggregate number of shares as to which Options may be granted shall be
subject to change only by means of an amendment  adopted in  accordance  with
Article XI below, subject to the provisions of Article VIII.

IV.  ADMINISTRATION OF THE PLAN

     The Plan shall be  administered  by the  Committee.  The  membership of the
Committee shall be determined,  and shall be subject to change without cause and
without notice from time to time, by the Board of Directors of the Company.

     The Committee is  authorized to interpret the  provisions of the Plan or of
any Option and to make all rules and  determinations  necessary or advisable for
the  administration of the Plan.  Subject to the provisions of the Plan, Options
may be granted upon such terms and conditions as the Committee may prescribe.

     This Plan is  intended  to comply in all  respects  with Rule  16b-3 or its
successors  promulgated  under the Securities  Exchange Act of 1934 ("1934 Act")
with respect to participants  who are subject to Section 16 of the 1934 Act, and
any  provision in this Plan with respect to such persons  contrary to Rule 16b-3
shall be  deemed  null  and void to the  extent  permissible  by law and  deemed
appropriate by the Committee.

V.   ELIGIBILITY FOR PARTICIPATION

     The Committee  shall  determine  which  employees  and  Directors  shall be
eligible to  participate  in the Plan.  Without  limiting the  generality of the
foregoing, Options may be awarded for reasons of performance,  merit, promotion,
bonus or upon new employees joining the Company or any Affiliate.

     The Committee  may grant to one or more such  employees or Directors one or
more Options, and shall designate the number of shares to be optioned under each
Option so granted;  provided,  however,  that no Options  shall be granted after
December  31,  2002.  In no event shall any  employee be granted in any calendar
year options to purchase or receive more than 1,200,000  shares of the Company's
Common Stock pursuant to this Plan.

VI.  TERMS AND CONDITIONS OF OPTIONS

     No Option issued  pursuant to this Plan shall be an incentive  stock option
under Section 422 of the Internal Revenue Code of 1986, as amended.  Each Option
shall be set forth in writing in an Option agreement, duly executed on behalf of
the Company and by the person to whom such Option is granted. No Option shall be
deemed  to have been  granted  and no  purported  grant of any  Option  shall be
effective  until such  Option  shall have been  approved by the  Committee.  The
Committee may provide that Options be granted

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subject to such  conditions  as the Committee  may deem  appropriate,  including
without  limitation,  subsequent  approval by the shareholders of the Company of
this Plan or any amendments thereto. Each such Option agreement shall be subject
to at least the following terms and conditions:

     A. Option  Price:  Except as otherwise  determined  by the  Committee,  the
Option price per share for Options  granted under the Plan shall be equal to the
fair market  value per share of Common Stock on the date of grant of the Option;
provided,  however, that in no event shall the Option price be less than the par
value per share of Common  Stock.  Fair market value shall be the average of the
"high"  and "low"  sale  prices  as  reported  in the  National  Association  of
Securities  Dealers Automated  Quotation System ("NASDAQ") for the date of grant
of the Option or, if none,  for the most recent trading date thirty (30) days or
less  prior to the date of grant of the  Option  on which the  Common  Stock was
traded.

     B. Term of Option: Each Option shall terminate not more than ten (10) years
from the date of the grant  thereof,  or at such  earlier  or later  time as the
Committee shall expressly resolve.

     C. Date of Exercise: The Committee may prescribe the date or dates on which
the Option becomes exercisable, and may provide that the Option rights accrue or
become exercisable in installments over a period of months or years, or upon the
attainment of stated goals.

     D. Cancellation and Repurchase Rights: The Committee may stipulate that any
Option which becomes exercisable shall be subject to cancellation or that shares
purchased upon the exercise of such Option shall be subject to repurchase rights
in favor of the Company. In such event the Committee shall determine the date or
dates, or event or events,  upon which such  cancellation  or repurchase  rights
shall become effective or shall lapse, as the case may be.

     E.  Medium of  Payment:  The Option  price  shall be  payable  upon the
exercise of the Option.  It shall be payable in cash,  or, if  permitted  by the
Committee, in shares or other consideration.

     F.  Termination  of  Employment:  An Option  holder who ceases (for any
reason other than death or total and  permanent  disability  or  termination  of
employment  for cause) to be an  employee  or  Director  of the Company or of an
Affiliate  may  exercise  any Option  granted  to the  extent  that the right to
purchase  shares  thereunder has accrued on the date of such  termination.  Such
Option  shall be  exercisable  only within  three (3) months  after such date of
termination, or, if earlier, within

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the  originally  prescribed  term of the  Option,  unless  the  Committee  shall
authorize a  different  period.  Employment  shall not be deemed  terminated  by
reason of a transfer to another employer which is the Company or an Affiliate.

     An Option  holder  whose  employment  with the Company or an  Affiliate  is
terminated  by his/her  employer for cause or a Director who is removed from the
Board of Directors for cause shall forthwith upon such termination cease to have
any right to exercise any Option. For purposes of this paragraph,  "cause" shall
be deemed to include  dishonesty with respect to the employer,  insubordination,
substantial  malfeasance or  non-feasance  of duty,  unauthorized  disclosure of
confidential information,  and conduct substantially prejudicial to the business
of the Company or any Affiliate.  The  determination  of the Committee as to the
existence of cause shall be conclusive.

     An Option  holder to whom an Option has been granted under the Plan who
is absent from work with the Company or with an  Affiliate  because of temporary
disability,  or who is on a permitted  leave of absence for any  purpose,  shall
not, during the period of any such absence,  be deemed by virtue of such absence
alone,  to have  terminated his employment with the Company or with an Affiliate
except as the Committee may otherwise expressly provide.

     G. Total and  Permanent  Disability:  If an Option  holder  ceases to be an
employee or Director  of the Company or of an  Affiliate  by reason of total and
permanent disability,  as determined by the Committee, any Option held by him or
her on the date of disability  shall be exercisable as to all or any part of the
shares  subject to the Option,  all of which  shares shall be fully vested as of
the date of such  disability.  A disabled Option holder may exercise such Option
only  within a period of one (1) year  after the date as of which the  Committee
determines that he or she became disabled or within such different period as may
be determined by the Committee, or, if earlier, within the originally prescribed
term of the Option.

     H. Death:  If an Option  holder dies while the Option holder is an employee
or Director of the Company or of an Affiliate,  any Option held by him or her at
the  date of  death  shall be  exercisable  as to all or any part of the  shares
subject to the Option,  all of which shares shall be fully vested as of the date
of the Option holder's  death. A deceased Option holder's legal  representatives
or  one  who  acquires  the  Option  by  will  or by the  laws  of  descent  and
distribution may exercise such Option only within a period of one (1) year after
the date of death or within such  different  period as may be  determined by the
Committee, or, if earlier, within the originally prescribed term of the Option.


<PAGE>

     I.  Exercise of Option and Issue of Shares:  Options shall be exercised
by giving written notice to the Company, addressed to the Company at the address
specified in the Option agreement, with which the Option holder shall tender the
Option price.  Such written notice shall be signed by the person  exercising the
Option,  shall  state the number of shares  with  respect to which the Option is
being exercised,  and shall contain any warranty  required by Article VII of the
Plan. The issuance of the Option shares may be delayed by the Company if any law
or regulation requires the Company to take any action with respect to the Option
shares prior to the issuance  thereof.  Without  limiting the  generality of the
foregoing,  nothing  contained  herein shall be deemed to require the Company to
issue any Option shares if prohibited by law or applicable regulation.

     The shares shall, upon issuance, be evidenced by an appropriate certificate
or certificates in respect of paid-up, non-assessable shares.

     J.  Assignability  and  Transferability  of Option: By its terms, an Option
granted to an Option  holder  shall not be  transferable  by such Option  holder
other  than  (i) by will or by the  laws of  descent  and  distribution  or (ii)
pursuant  to a qualified  domestic  relations  order,  as defined by the Code or
Title 1 of the Employee  Retirement Income Security Act or the rules thereunder,
or  (iii)  as  otherwise  determined  by the  Committee  and  set  forth  in the
applicable Option agreement. The designation of a beneficiary of an Option by an
Option  holder  shall not be deemed a  transfer  prohibited  by this  paragraph.
Except as provided in the preceding  sentence,  an Option shall be  exercisable,
during an Option holder's lifetime,  only by the Option holder (or by his or her
legal representative) and shall not be assigned, pledged, or hypothecated in any
way  (whether  by  operation  of law or  otherwise)  and shall not be subject to
execution,  attachment or similar process.  Any attempted transfer,  assignment,
pledge,  hypothecation,  or other  disposition  of any  Option or of any  rights
granted thereunder contrary to the provisions of this Paragraph,  or the levy of
any attachment or similar process upon an Option or other such rights,  shall be
null and void.

     K. Other Provisions:  The Option agreements authorized under the Plan shall
be subject to such other terms and conditions,  including,  without  limitation,
restrictions  upon the  exercise  of the  Option,  as the  Committee  shall deem
advisable.

     L. Non-Employee, Non-Scientific Board Directors' Options: Each Director who
is not (i) an employee of the Company or any of its Affiliates, or (ii) a member
of the  Scientific  Board  of the  Company,  or  (iii)  elected  pursuant  to an
agreement or arrangement


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between shareholders of the Company or between the Company and its shareholders,
upon first being appointed or elected to the Board of Directors,  and upon every
third anniversary thereof,  shall be granted an Option to purchase 30,000 shares
of Common Stock. Each such Option shall have an exercise price equal to the fair
market value per share of Common Stock on the date of grant, as determined under
Section VI.A.  above,  and a term of ten (10) years, and shall be exercisable as
to one-third  (1/3) of the shares  subject  thereto upon  completion of one full
year of service on the Board of Directors after the date of grant,  and as to an
additional  one-third  (1/3)  upon  completion  of each  full  year  of  service
thereafter.  For any such  Director  serving in office on December 6, 1991,  the
first such Option  shall be granted on the date on which the most recent  Option
previously  granted to him, the vesting of which is  contingent  upon  continued
service on the Board of Directors,  becomes fully vested, and subsequent Options
under this Paragraph  shall be granted on every third  anniversary of such date.
Notwithstanding  the provision of Section XI  concerning  amendment of the Plan,
the  provisions of this Section VI.L.  shall not be amended more than once every
six months,  other than to comport with changes in the Internal  Revenue Code of
1986,  as amended,  the Employee  Retirement  Income  Security Act, or the rules
thereunder.  The grants of options  under this  Paragraph  L are  intended to be
non-discretionary  formula  awards  within the meaning of Rule  16b-3(c)(2)(ii).
Paragraph  F of  Article  VI,  which  cancels  the  Options  of any  Participant
determined by the Committee to have been  terminated for cause,  shall not apply
to the awards under this Paragraph L.

     M. Tax Withholding:  In the event that any federal,  state, or local income
taxes,  employment  taxes,  Federal  Insurance  Contributions  Act  ("F.I.C.A.")
withholdings  or other  amounts are required by applicable  law or  governmental
regulation to be withheld from the Option holder's salary in connection with the
exercise of an Option,  the Option  holder shall advance in cash to the Company,
or to any Affiliate of the Company which employs or employed the Option  holder,
the amount of such  withholdings  unless a  different  withholding  arrangement,
including the use of shares of the Company's  Common Stock, is authorized by the
Committee  (and  permitted  by law),  provided,  however,  that with  respect to
persons subject to Section 16 of the 1934 Act, any such withholding  arrangement
shall be in compliance with any applicable  provisions of Rule 16b-3 promulgated
under Section 16 of the 1934 Act. For purposes hereof,  the fair market value of
the shares withheld for purposes of payroll  withholding  shall be determined in
the manner provided in Section VI.A.  above,  as of the most recent  practicable
date  prior to the date of  exercise.  If the fair  market  value of the  shares
withheld is less than the amount of payroll  withholdings  required,  the Option
holder may be


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required to advance the difference in cash to the Company or the Affiliate
employer.

     N. Reload Options:  The Committee may authorize reload options ("Reload
Options") to purchase for cash or shares a number of shares of Common Stock. The
number of Reload  Options  shall equal (i) the number of shares of Common  Stock
used to exercise the underlying Options and (ii) to the extent authorized by the
Committee,  the  number  of  shares  of Common  Stock  used to  satisfy  any tax
withholding  requirement incident to the exercise of the underlying Options. The
grant of a Reload Option will become  effective  upon the exercise of underlying
Options  through the use of shares of Common  Stock held by the  optionee for at
least 6  months.  Reload  Options  must be  evidenced  in Option  agreements  or
amendments  to those  agreements.  The  Option  price per share of Common  Stock
deliverable  upon the exercise of a Reload Option shall be the fair market value
of a share of Common  Stock on the date the grant of the Reload  Option  becomes
effective. The term of each Reload Option shall be equal to the remaining option
term of the underlying  Option. No additional Reload Options shall be granted to
Option holders when Options and/or Reload Options are exercised  pursuant to the
terms of this Plan following termination of the Option holder's employment or on
account of death or total and permanent disability. All other provisions of this
Plan with respect to Options shall apply equally to Reload Options.

     O.  Rights  as a  Shareholder:  No Option  holder  shall  have  rights as a
shareholder  with respect to any shares covered by such Option except as to such
shares as have been  registered in the Company's  share  register in the name of
such person upon the due exercise of the Option.

VII. PURCHASE FOR INVESTMENT

     If and to the  extent  that the  issuance  of  shares  pursuant  to the
exercise of Options is deemed by the Company to be subject to the United  States
Securities Act of 1933, as now in force or hereafter amended ("1933 Act"), or to
the  securities  law of any other  jurisdiction,  the Company  shall be under no
obligation to issue shares covered by such exercise unless the person or persons
who  exercises or who exercise such Option shall make such warranty or take such
action as may be required by any  applicable  securities  law of any  applicable
jurisdiction and shall, in the case of the applicability of the 1933 Act, in the
absence of an effective registration under such Act with respect to such shares,
warrant to the  Company,  at the time of such  exercise,  that such person is or
that they are  acquiring  the  shares  to be  issued to such  person or to them,
pursuant to such exercise of the Option,  for investment and not with a view to,
or for sale in connection with, the distribution of any such shares; and in such

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events  the  person  or  persons  acquiring  such  shares  shall be bound by the
provisions  of a legend  endorsed  upon any share  certificates  expressing  the
requirements of any applicable  non-United  States  securities law, or, in cases
deemed governed by the 1933 Act, substantially the following legend, which shall
be endorsed upon the certificate or certificates evidencing the shares issued by
the Company pursuant to such exercise:

     "The shares have not been  registered  under the securities laws of any
country, including the United States Securities Act of 1933, as amended, and the
Company  may refuse to permit the sale or  transfer  of all or any of the shares
until (1) the Company has  received  an opinion of Counsel  satisfactory  to the
Company that any such transfer is exempt from registration  under all applicable
securities  laws or (2) in the case of sales or  transfers  to which the  United
States  Securities  Act of 1933 is applicable,  unless a registration  statement
with respect to such shares shall be effective under such Act, as amended."

      Without limiting the generality of the foregoing, the Company may delay
issuance  of the  shares  until  completion  of any action or  obtaining  of any
consent which the Company deems  necessary  under any  applicable law (including
without limitation state securities or "blue sky" laws).

VIII. ADJUSTMENTS UPON CHANGES IN CAPITALIZATION

      In the event that the  outstanding  Common Stock,  $.01 par value,  of the
Company is changed into or exchanged for a different number or kind of shares or
other  securities  of the  Company  or of another  corporation  by reason of any
reorganization,  merger,  consolidation,   recapitalization,   reclassification,
change in par value,  stock split-up,  combination of shares or dividend payable
in  capital  stock,  or the like,  appropriate  adjustment  shall be made in the
number and kind of shares for the purchase of which Options may be granted under
the Plan,  including Options to be granted pursuant to Article VI L hereof, and,
in  addition,  appropriate  adjustment  shall be made in the  number and kind of
shares and in the Option price per share subject to outstanding  Options so that
each Option holder shall be in a position  equivalent to the position the Option
holder  would  have  been  in  had  the  Option  holder  exercised  the  Options
immediately prior to the applicable event.

IX.  DISSOLUTION OR LIQUIDATION OF THE COMPANY

     Upon the dissolution or liquidation of the Company other than in connection
with transactions to which the preceding Article VIII is applicable, all Options
granted hereunder shall terminate and become null and void;  provided,  however,
that if the rights hereunder of an Option holder or one who acquired an

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Option by will or by the laws of descent  and  distribution  have not  otherwise
terminated  and expired,  the Option  holder or such person shall have the right
immediately  prior to such  dissolution  or  liquidation  to exercise any Option
granted hereunder to the extent that the right to purchase shares thereunder has
accrued as of the date of  exercise  immediately  prior to such  dissolution  or
liquidation.

X.   TERMINATION OF THE PLAN

     Unless the  Committee  shall  decide to reduce or,  subject to  shareholder
approval,  if required under Article XI, to extend the duration of the Plan, the
Plan shall  terminate on December 31,  2002.  Termination  of the Plan shall not
affect  any  Options  granted  or any Option  agreements  executed  prior to the
effective date of termination.

XI.  AMENDMENT OF THE PLAN

     The Plan may be amended by the  Committee  or the Board of Directors of the
Company  provided,  however,  that if the scope of any  amendment  is such as to
require  shareholder  approval in order to comply with Rule 16b-3 under the 1934
Act such amendment  shall require  approval by the  shareholders.  Any amendment
shall not affect  any  Options  theretofore  granted  and any Option  agreements
theretofore  executed by the Company and any Option holder unless such amendment
shall  expressly so provide.  No  amendment  shall  adversely  affect any Option
holder with respect to an outstanding Option without the written consent of such
Option holder. With the consent of the Option holder affected, the Committee may
amend any outstanding  Option  agreement in a manner not  inconsistent  with the
Plan, including,  without limitation,  to accelerate the date of exercise of any
installment of any Option.

XII. EMPLOYMENT RELATIONSHIP

     Nothing  herein  contained  shall be deemed to  prevent  the  Company or an
Affiliate from  terminating  the employment of any employee,  nor to prevent any
employee from terminating his/her employment with the Company or an Affiliate.

XIII.EFFECTIVE DATE

     This Plan first became effective on January 2, 1985.