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                                  Exhibit 10.31

January 8, 2003

Kathryn L. Biberstein
[address]

Dear Kathy:

On behalf of Alkermes, Inc., I am pleased to offer you the position of Vice
President, General Counsel reporting to Richard Pops, Chief Executive Officer.

1.    Effective Date: Following your acceptance of our offer we would expect to
      establish a mutually acceptable start date for your employment. Based on
      communication we have already had on this subject, this offer is extended
      with the understanding that you will use your best efforts to establish a
      start date that is not later than March 3, 2003.

2.    Compensation: Your base compensation will initially be $230,000 per annum
      which is equal to approximately 90% of the full-time annual rate for you
      in this position. This figure was developed based on a normal weekly
      schedule of three days in Cambridge and two half days in Maine. You will
      be paid biweekly in accordance with the Company's payroll procedures. Your
      initial salary review will be in January 2004 and annually thereafter.
      Salary reviews will be based on your performance and the Company's
      performance.

      You will also receive a sign-on bonus of $25,000 payable within 30 days of
      the start of your employment. You will be eligible for a performance bonus
      in January 2004.

3.    Benefits: You and your dependents will be eligible for Alkermes' standard
      medical, dental, and disability benefits, plus life insurance equal to (2)
      times your annual salary, all of which is paid for by the Company. You
      will also be able to participate in our Section 125 cafeteria plan for
      medical and/or dependent care expenses at the start of your employment.
      You will be able to participate in Alkermes' 401(k) plan, which includes a
      company match of 50% of the first 6% of compensation deferred into the
      plan, beginning on April 1, 2003. Vacation accrual will be at the rate of
      four (4) weeks per year. Standard paid holidays will be observed.
      Transportation benefits to assist you with your commute from your home to
      your Alkermes location will consist of one of the following: subsidized
      on-site parking or reimbursement for a MBTA pass in accordance with
      company policy. The Company reserves the right to modify its employee
      benefits programs from time-to-time.
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K. Biberstein
January 8, 2003

      If you should elect to move your home from Maine to Massachusetts we will
      also provide you with the following benefits in order to assist you with
      the relocation These benefits will remain available to you during your
      first three years of employment. After that time this provision of our
      offer will lapse.

      A.    Pay for the move of your household goods from Freeport, Maine to
            your new home in Massachusetts.

      B.    Reimburse the reasonable and customary costs including real estate
            commissions, legal and title fees, transfer or documentary taxes you
            are required to pay, and mortgage prepayment penalty charges that
            you incur in selling your home in Maine. If you should elect to
            lease your house in Maine instead of selling it upon moving to
            Massachusetts, we agree to reimburse you reasonable maintenance and
            management costs for up to three years.

      C.    Reimburse the reasonable and customary costs you incur in purchasing
            a home in Massachusetts including legal and title fees, appraisal
            and inspection fees and other required costs.

      D.    A relocation allowance of $50,000 which will be payable in two equal
            payments of $25,000. The first payment will be made at the time you
            sign a purchase and sale agreement for a house in Massachusetts, and
            the second payment will be made on the one-year anniversary of the
            purchase and sale.

      E.    Any of the above benefits, which require reporting to the IRS, will
            be grossed-up for tax purposes at year-end.

      The offer of relocation assistance we have described above is made with
      the understanding that you will reimburse the Company for a fraction of
      the costs which Alkermes actually incurs for items A - E above if you
      should resign within one year of your move from Maine to Massachusetts.
      The fraction you agree to reimburse Alkermes will be determined as
      follows: the denominator shall be twelve and the numerator shall be twelve
      minus the number of complete months of your employment following your
      move. Your agreement to reimburse the Company as described above will be
      waived if you should resign from the company as the result of a change in
      control or after a substantial change in either your job responsibilities
      or job location.

4.    Equity Participation, Vesting of Stock: Subject to approval by the
      Compensation Committee of The Board of Directors, you will be granted a
      ten (10) year stock option exercisable for 225,000 shares of Alkermes,
      Inc., Common Stock at an exercise price equal to the current fair market
      value of the Company's Common Stock on the date you start your employment
      with Alkermes. This option will vest equally over four (4) years on the
      anniversary of your hire date, provided that you remain employed by the
      Company. In the event of termination of your employment for any reason,
      vesting shall cease. We will provide you with a copy of the Company's
      Omnibus Stock Option Plan for complete details.


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K. Biberstein
January 8, 2003

5.    Employment Period: Your employment with the Company will be at-will,
      meaning that you will not be obligated to remain employed by the Company
      for any specified period of time; likewise, the Company will not be
      obligated to continue your employment for any specific period and may
      terminate your employment at any time, with or without cause.

      In the event of termination of your employment by Alkermes, we shall
      provide you with notice of such termination at least 30 days prior to the
      intended date of termination. Notwithstanding this, upon delivering such
      notice, Alkermes may terminate your ability to act on behalf of the
      Company and may require that your duties be limited or discontinued.

      If Alkermes terminates your employment because of your (a) commission of a
      felony or other unlawful acts having significant deleterious effect on
      Alkermes, (b) perpetration of common law fraud against Alkermes, or (c)
      breach of confidential trade secret information, Alkermes shall have no
      further obligations to you.

      If Alkermes terminates your employment for any other reason than stated in
      the paragraph immediately above, Alkermes will pay you at the monthly rate
      of your then current annual base salary for up to nine months or until you
      find other replacement employment, whichever occurs first. The Company
      will have no further financial obligation to you other than this
      termination pay.

6.    Change In Control: Alkermes will enter into its standard Change In Control
      Employment Agreement with you effective at the start of your employment. A
      copy of the agreement will be provided to you.

7.    Employment Eligibility Verification: Please note that all persons in the
      United States are required to complete an Employment Eligibility
      Verification Form on the first day of employment and submit an original
      document or documents that establish identity and employment eligibility
      within three (3) business days of employment. For your convenience, we are
      enclosing Form I-9 for your review. You will need to complete Section 1
      and present original document(s) of your choice as listed on the reverse
      side of the form once you begin work.

8.    Proprietary Information, No Conflicts: You agree to execute the Company's
      standard Employee Agreement With Respect to Inventions and Proprietary
      Information and Covenant Not to Compete and to be bound by all of the
      provisions thereof. A copy of each is enclosed with this letter. You
      hereby represent that you are not presently bound by any employment
      agreement, confidentiality or proprietary information agreement or similar
      agreement with any current or previous employer that would impose any
      restriction on your acceptance of this offer or that would interfere with
      your ability to fulfill the responsibilities of your position with the
      Company.


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K. Biberstein
January 8, 2003

Kathy, all of us here at Alkermes are very enthusiastic about the prospect of
you joining the Company and have the highest expectation of your future
contributions.

Please indicate your acceptance of the foregoing by signing one of the duplicate
originals of this letter and returning it to me at Alkermes no later than
January 14, 2003. After that date, this offer will lapse.

You may return this entire letter, with your signature, and the benefits
information completed below, by fax to (617) 494-5360 with the original to
follow and marked confidential. Due to the confidential nature of this document
please do not fax it back using any other number. The other duplicate original
is for your records.

Yours truly,
ALKERMES, INC.

/s/ Peter Maguire

Peter Maguire
Director, Human Resources

The foregoing is signed and accepted as of the date first above written by:


 /s/ Kathryn Biberstein                                      January 14, 2003
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Kathryn Biberstein                                        Date


Enclosures
01-226


           Please Complete the Following for your Benefits Enrollment

Legal Name
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Date of Birth
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M           F
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Social Security #:
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