Document:

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                                                                   EXHIBIT 10.15

[PREDIX PHARMACEUTICALS LOGO]           10 K GILL STREET
                                        Woburn, MA 01801
                                        Telephone: 781-376-0821

September 24, 2004

Stephen R. Donahue, M.D.
[ADDRESS]

Re: Employment Agreement

Dear Steve,

      This letter is to confirm our understanding with respect to your future
employment by Predix Pharmaceutical Holdings Inc. or its parent, subsidiaries or
affiliates (the "Company"). The terms and conditions agreed to in this letter
shall hereinafter be referred to as the "Agreement." In consideration of the
mutual promises and covenants contained in this Agreement, and for other good
and valuable consideration, the receipt and sufficiency of which are hereby
mutually acknowledged, we have agreed as follows:

      1. Employment. Employee will be expected to work Monday through Thursday
at the Company Headquarters (in Woburn or other corporate designated location)
for a period of no more than 8 months from the date of hire. During this period
not to exceed 8 months, employee will be expected to work on Fridays from a
location which he deems appropriate. Thereafter, employee will be expected to
work Monday through Friday at the Company Headquarters (in Woburn or other
corporate designated location)

      2. Commencement Date. This offer for the position of Vice President of
Clinical and Regulatory Affairs reporting to me, Michael Kauffman, CEO and
President, stands open until September 30, 2004. Predix would like you to start
as soon as possible but no later than October 27, 2004. In this position, you
are part of the Executive Team of Predix. You will be expected to attend a
Pre-IND Briefing Meeting with FDA on October 14, 2004, and to be present with
the Predix Team on October 13, 2004, for a rehearsal session.

      3. Employment at Will. Your employment hereunder is terminable by either
party "at will." It is entirely voluntary for both parties and either you or the
Company may terminate the employment relationship at any time for any reason. No
provision of this Agreement shall be deemed to alter the "at will" nature of
this relationship. In the event that employment is terminated without cause by
the Company, employee will be granted six (6) months of severance at the current
salary, including employment benefits during that period. Cause for termination
shall not include economic and restructuring causes.

      4. Compensation. Subject to your acceptance of the position offered to you
upon the terms and conditions herein, the Company will provide you with the
following compensation:

      (a) Salary. You shall be paid from the Company's payroll. For your
services hereunder you shall be paid a base salary of $250,000.00 per year,
which shall be paid in accordance with the Company's payroll practices as in
effect from time to time, less any amounts required to be withheld under
applicable law.

      (b) Moving Allowance: The Employee shall be reimbursed up to $25,000.00
for moving expenses pursuant to the corporate moving policy Section 1
(attached). Please note that all moving reimbursements will be made based on
receipts for moving services rendered pursuant to the Predix Relocation Benefits
Policy.

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      (c) Sign-On Bonus. Signing Bonus - The Employee shall be entitled to a one
time gross signing bonus of twenty five thousand dollars ($25,000.00) due on the
Employment Date.

      (d) Annual Bonus. You will be eligible to participate in the Company's
bonus program, in the amount of up to forty thousand dollars ($40,000.00), which
is based on successful achievement of annual corporate goals and approval by the
Board of Directors.

      Notwithstanding anything contained herein to the contrary, all bonus
payments remain unearned until they become payable in accordance with the
Company's standard policies, practices and procedures. All bonus plans may be
amended, modified or terminated by the Company at any time.

      (e) Stock Options. Subject to the terms and conditions of the Predix
Pharmaceutical Holdings, Inc. Share Option Plan and the execution of an option
agreement executed pursuant thereto with the Employee, the Employee shall be
granted options to purchase 1,090,929 shares of the Company's common stocks, at
an exercise price to be determined within 90 days of the hire date(the
"Options"). The Options granted hereunder shall vest over a period of sixteen
(16) quarters with six and a quarter (6.25) percent of the options become
exercisable every three months beginning three months following the Employment
Date. All stock option grants are contingent upon approval by the Compensation
Committee of the Company's Board of Directors and are priced according to the
grant date, which is your date of hire. The exercise price will be the fair
market value of the stock on the grant date. Notwithstanding the foregoing,
these options shall not be exercisable for any Shares until the date that the
Employee has been employed by the Company for a period of one year. In case the
company merges, acquires and is acquired by another corporation ("M&A") and
there is a change of control in the Company event, the company will accelerate
100% of the vesting in case: (a) The Employee is offered a job with no equal
responsibility and leaves the company within 12 month following the M & A; or
(2) The employee is terminated within 12 month following the M & A; or (3) there
is no rollover of the Company's options into a new option plan following the
M&A.

      Additional option grants to purchase company stock may be considered
annually based upon your satisfaction of performance criteria to be mutually
agreed upon by you and the Company

      5. Employee Benefit Plans. Commencing on your Employment Date, the Company
shall provide the Employee with the option to select hospitalization, medical
and dental insurance pursuant to terms determined by the Company and its
insurer.

      6. Time Off. The Employee shall be entitled to twenty days of paid time
off (WYN days: When You Need It) for reasons determined by the employee during
each calendar year. Five (5) days of unused "as you need it" time may be accrued
and carried over into the next year for an annual total not to exceed 25 days.
The Employee shall also be entitled to paid time off on all holidays recognized
by the Company.

      7. No Conflicting Agreements. You hereby represent and warrant that you
have no commitments or obligations inconsistent with this Agreement and you
hereby agree to indemnify and hold the Company harmless against loss, damage,
liability or expense arising from any claim based upon circumstances alleged to
be inconsistent with such representation and warranty.

      8. Protected Information. As used in this Agreement, the term "Inventions"
means all ideas, discoveries, creations, manuscripts and properties,
innovations, improvements, know-how, inventions, designs, developments,
apparatus, techniques, methods, biological processes, cell lines, laboratory
notebooks and formulae, whether or not patentable or copyrightable, including
all rights to obtain, register, perfect and enforce these proprietary interests.
You shall at all times, both during and after any termination of this Agreement
by either you or the Company, maintain in confidence and shall not, without the
prior written consent of the Company, use, except in the course of performance
of your duties for the Company,

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disclose or give to others any fact or information which was disclosed to or
developed by you during the course of performing services for, or receiving
training from, the Company, and which is not generally available to the public,
including but not limited to information and facts concerning business plans,
customers, future customers, suppliers, licensors, licensees, partners,
investors, affiliates or others, training methods and materials, financial
information, sales prospects, client lists, Inventions, or any other scientific,
technical, trade or business secret or confidential or proprietary information
of the Company or of any third party provided to you during the Term. In the
event you are questioned by anyone not employed by the Company or by an employee
of or a consultant to the Company not authorized to receive such information, in
regard to any such information or any other secret or confidential work of the
Company, or concerning any fact or circumstance relating thereto, you will
promptly notify the president of the Company.

      9. Prohibited Competition.

      (a) Certain Acknowledgments and Agreements.

            (i) You recognize and acknowledge the competitive and proprietary
nature of the Company's business operations. You acknowledge and agree that a
business will be deemed competitive with the Company if it engages in a line of
business in which it performs any of the services, conducts research, or
develops, manufactures or sells any products provided or offered by the Company
or under development by the Company, or any similar products or products
fulfilling the same function, whether or not similar, in the Field of Interest
(such business to be referred to as a "competitive business"). The term "Field
of Interest" currently means the field of diagnosis, prevention or treatment of
diseases or conditions in humans relating to central nervous system and diseases
treated with serotonergic agents. You further understand that the Company may
expand the definition of its Field of Interest at any time by action of its
Board of Directors, which new definition will be binding upon you ten (10) days
after written notice to you of such change.

            (ii) You further acknowledge and agree that during the course of
performing services for the Company, the Company will furnish, disclose or make
available to you confidential and proprietary information related to the
Company's business. You also acknowledge that such confidential information to
be provided by the Company has been developed and will be developed by the
Company through the expenditure by the Company of substantial time, effort and
money and that all such confidential information could be used by you or a
competitive business to compete with the Company.

      (b) Covenants Not to Compete. During the period in which you are employed
by the Company (the "Term") and for a period of one year following the
expiration or termination of the Term, whether such termination is voluntary or
involuntary, you shall not, without the prior written consent of the Company:

            (i) for yourself or on behalf of any other person or entity,
directly or indirectly, either as principal, agent, stockholder, employee,
consultant, representative or in any other capacity, own, manage, operate or
control, or be concerned, connected or employed by, or otherwise associate in
any manner with, engage in or have a financial interest in any competitive
business anywhere in the world (the "Restricted Territory"), except that nothing
contained herein shall preclude you from purchasing or owning securities of any
such business if such securities are publicly traded, and provided that your
holdings do not exceed one (1 %) percent of the issued and outstanding
securities of any class of securities of such business; or

            (ii) either individually or on behalf of or through any third party,
solicit, divert or appropriate or attempt to solicit, divert or appropriate, for
the purpose of competing with the Company or any present or future parent,
subsidiary or other affiliate of the Company which is engaged in a similar
business as the Company, any customers or patrons of the Company, or any
prospective customers or patrons with respect to which the Company has developed
or made a sales presentation (or similar offering

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of services), located within the Restricted Territory; or

            (iii) either individually or on behalf of or through any third
party, directly or indirectly, solicit, entice or persuade or attempt to
solicit, entice or persuade any other employees of or consultants to the Company
or any present or future parent, subsidiary or affiliate of the Company to leave
the services of the Company or any such parent, subsidiary or affiliate for any
reason.

      (c) Reasonableness of Restrictions. You further recognize and acknowledge
that (i) the types of employment which are prohibited by this Section 9 are
reasonable in relation to the skills which represent your principal salable
asset both to the Company and to your other prospective employers, and (ii) the
geographical scope of the provisions of this Section 9 is reasonable, legitimate
and fair to you in light of the Company's need to market its services and sell
its products worldwide in order to have a sufficient customer base to make the
Company's business profitable and in light of the limited restrictions on the
type of employment prohibited herein compared to the types of employment for
which you are qualified to earn your livelihood.

      (d) Survival of Acknowledgments and Agreements. Your acknowledgments and
agreements set forth in this Section 9 shall survive the expiration or
termination of this Agreement and the termination of your employment with the
Company for any reason.

10. Ownership of Ideas, Copyrights and Patents.

      (a) Property of the Company. You agree that all inventions which you may
conceive, reduce to practice or develop during the Term (or, if based on or
related to any confidential or proprietary information of the Company, within
one (1) year after the termination of such employment), alone or in conjunction
with another, or others, whether during or out of regular business hours, and
whether at the request or upon the suggestion of the Company, or otherwise,
shall be the sole and exclusive property of the Company (the "Company
inventions"), that you will promptly disclose all such inventions to the
Company, and that you shall not publish any of the Company inventions without
the prior written consent of the Company. You hereby assign to the Company all
of your right, title and interest in and to all of the foregoing. You further
agree to use your best efforts to ensure that none of the Company Inventions
will violate or infringe upon any right, patent, copyright, trademark or right
of privacy, or constitute libel or slander against or violate any other rights
of any person, firm or corporation.

You have attached hereto as Schedule A (i) a list of all inventions in which you
have any right, title, or interest as of the date of your execution of this
Agreement ("Other inventions"), and (ii) a list of all Other inventions made,
conceived, or developed, in whole or in part, by you prior to the date of your
execution of this Agreement, and you represent that Schedule A is a complete and
accurate list of all Other inventions.

      (b) Cooperation. You agree that you will fully cooperate with the Company,
its attorneys and agents in the preparation and filing of all papers and other
documents as may be required to perfect the Company's rights in and to any of
such Company Inventions, including, but not limited to, performing all acts
deemed necessary or desirable by the Company (both during and after your
employment with the Company) and joining in any proceeding to obtain letters
patent, copyrights, trademarks or other legal rights of the United States and of
any and all other countries on such Company Inventions; provided, that, the
Company will bear the expense of all such proceedings. You hereby agree that any
patent or other legal right covering any Company Invention issued to you
personally, shall be assigned by you to the Company without charge by you.

<PAGE>

      (c) Works Made For Hire. Without limiting the foregoing, you further
acknowledge that all original works of authorship made by you, whether alone or
jointly with others within the scope of your employment with the Company and
which are protectable by copyright are "works made for hire" within the meaning
of the United States Copyright Act, 17 U.S.C. Section 101, as amended, the
copyright of which shall be owned solely, completely and exclusively by the
Company. If any Company invention is considered to be work not included in the
categories of work covered by the United States Copyright Act, 17 U.S.C. Section
101, as amended, such work shall be owned solely by, or hereby assigned or
transferred completely and exclusively to, the Company.

      11. Disclosure to Future Employers. You agree that you will provide, and
that the Company may similarly provide in its discretion, a copy of the
covenants contained in Sections 8, 9 and 10 of this Agreement to any business or
enterprise which you may directly, or indirectly, own, manage, operate, finance,
join, control or in which you participate through the ownership, management,
operation, financing, or control, or with which you may be connected as an
officer, director, employee, partner, principal, agent, representative,
consultant or otherwise.

      12. Representations Regarding Prior Work and Legal Obligations.

      (a) You represent that you have no agreement or other legal obligation
with any prior employer or any other person or entity that restricts your
ability to engage in employment discussions with, employment with, or to perform
any function for the Company.

      (b) You represent that you have been advised by the Company that at no
time should you divulge to or use for the benefit of the Company any trade
secret or confidential or proprietary information of any previous employer. You
acknowledge that you have not divulged or used any such information for the
benefit of the Company.

      (c) You represent that you have not and will not misappropriate any Other
Invention that you played any part in creating while working for any former
employer.

      (d) You acknowledge that the Company is basing important business
decisions on these representations, and affirm that all of the statements
included herein are true.

      13. Records. Upon termination of your relationship with the Company, you
shall deliver to the Company any property of the Company which may be in your
possession including products, materials, memoranda, notes, records, reports,
writings, drawings, diskettes, models and other materials or other documents or
photocopies of the same in any tangible form whatsoever constituting
confidential or proprietary information of the Company, and any of the foregoing
in intangible form.

      14. General.

      (a) Notices. All notices, requests, consents and other communications
hereunder shall be in writing, shall be addressed to the receiving party's
address set forth below or to such other address as a party may designate by
notice hereunder, and shall be either (i) delivered by hand, (ii) made by telex,
telecopy or facsimile transmission, (iii) sent by overnight courier, or (iv)
sent by registered mail, return receipt requested, postage prepaid.

<PAGE>

      If to the Company:

      Predix Pharmaceutical Holdings, Inc.
      10 K Gill Street
      Woburn, MA 01801 Attention: President & CEO Telephone: 781.376.0821
      Facsimile: 781.376.0822

      If to you:

      To the address set forth on the signature page of this Agreement.

      All notices, requests, consents and other communications hereunder shall
be deemed to have been given either (i) if by hand, at the time of the delivery
thereof to the receiving party at the address of such party set forth above,
(ii) if made by telex, te1ecopy or facsimile transmission, at the time that
receipt thereof has been acknowledged by electronic confirmation or otherwise,
(iii) if sent by overnight courier, on the next business day following the day
such notice is delivered to the courier service, or (iv) if sent by registered
mail, on the fifth business day following the day such mailing is made.

      (b) Entire Agreement. This Agreement embodies the entire agreement and
understanding between the parties hereto with respect to the subject matter
hereof and supersedes all prior oral or written agreements and understandings
relating to the subject matter hereof. No statement, representation, warranty,
covenant or agreement of any kind not expressly set forth in this Agreement
shall affect, or be used to interpret, change or restrict, the express terms and
provisions of this Agreement.

      (c) Modifications and Amendments. The terms and provisions of this
Agreement may be modified or amended only by written agreement executed by the
parties hereto.

      (d) Waivers and Consents. The terms and provisions of this Agreement may
be waived, or consent for the departure there for granted, only by written
document executed by the party entitled to the benefits of such terms or
provisions. No such waiver or consent shall be deemed to be or shall constitute
a waiver or consent with respect to any other terms or provisions of this
Agreement, whether or not similar. Each such waiver or consent shall be
effective only in the specific instance and for the purpose for which it was
given, and shall not constitute a continuing waiver or consent.

      (e) Assignment. The Company may assign its rights and obligations
hereunder to any person or entity that succeeds to all or substantially all of
the Company's business or that aspect of the Company's business in which you are
principally involved. Your rights and obligations under this Agreement may not
be assigned by you without the prior written consent of the Company.

      (f) Benefit. All statements, representations, warranties, covenants and
agreements of this Agreement shall be binding on the parties hereto and shall
inure to the benefit of the respective successors and permitted assigns of each
party hereto. Nothing in this Agreement shall be construed to create any rights
or obligations except between the parties hereto, and no person or entity shall
be regarded as a third-party beneficiary of this Agreement, other than any
future parent, subsidiary or affiliate of the Company.

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      (g) Governing Law. This Agreement and the rights and obligations of the
parties hereunder shall be construed in accordance with and governed by the law
of the Commonwealth of Massachusetts, without giving effect to the conflict of
law principles thereof.

      (h) Jurisdiction and Service of Process. Any legal action or proceeding
with respect to this Agreement may be brought solely in the courts of the
Commonwealth of Massachusetts or of the United States of America for the
District of Massachusetts. By execution and delivery of this Agreement, each of
the parties hereto accepts for itself and in respect of its property, generally
and unconditionally, the jurisdiction of the aforesaid courts. Each of the
parties hereto irrevocably consents to the service of process of any of the
aforementioned courts in any such action or proceeding by the mailing of copies
thereof by certified mail, postage prepaid, to the party at its address set
forth in Section 13(a) hereof.

      (i) Severability. The parties intend this Agreement to be enforced as
written. However, (i) if any portion or provision of this Agreement shall to any
extent be declared illegal or unenforceable by a duly authorized court having
jurisdiction, then the remainder of this Agreement, or the application of such
portion or provision in circumstances other than those as to which it is so
declared illegal or unenforceable, shall not be affected thereby, and each
portion and provision of this Agreement shall be valid and enforceable to the
fullest extent permitted by law; and (ii) if any provision, or part thereof, is
held to be unenforceable because of the duration of such provision or the
geographic area covered thereby, the Company and you agree that the court making
such determination shall have the power to reduce the duration and/or geographic
area of such provision, and/or to delete specific words and phrases
("blue-penciling"), and in its reduced or blue-penciled form such provision
shall then be enforceable and shall be enforced.

      (j) Headings and Captions. The headings and captions of the various
subdivisions of this Agreement are for convenience of reference only and shall
in no way modify, or affect the meaning or construction of any of the terms or
provisions hereof.

      (k) Injunctive Relief. You hereby expressly acknowledge that any breach or
threatened breach of any of the terms and/or conditions set forth in this
Agreement will result in substantial, continuing and irreparable injury to the
Company. Therefore, you hereby agree that, in addition to any other remedy that
may be available to the Company, the Company shall be entitled to injunctive or
other equitable relief by a court of appropriate jurisdiction in the event of
any breach or threatened breach of the terms or conditions of this Agreement.
The seeking of such injunction or order shall not affect the Company's right to
seek and obtain damages or other equitable relief on account of any such actual
or threatened breach. Nothing in this paragraph shall be construed to limit the
remedies for any actual or threatened breach that would otherwise be available
to the Company.

      (l) No Waiver of Rights, Powers and Remedies. No failure or delay by a
party hereto in exercising any right, power or remedy under this Agreement, and
no course of dealing between the parties hereto, shall operate as a waiver of
any such right, power or remedy of the party. No single or partial exercise of
any right, power or remedy under this Agreement by a party hereto, nor any
abandonment or discontinuance of steps to enforce any such right, power or
remedy, shall preclude such party from any other or further exercise thereof or
the exercise of any other right, power or remedy hereunder. The election of any
remedy by a party hereto shall not constitute a waiver of the right of such
party to pursue other

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available remedies. No notice to or demand on a party not expressly required
under this Agreement shall entitle the party receiving such notice or demand to
any other or further notice or demand in similar or other circumstances or
constitute a waiver of the rights of the party giving such notice or demand to
any other or further action in any circumstances without such notice or demand.

      (m) Counterparts. This Agreement may be executed in one or more
counterparts, and by different parties hereto on separate counterparts, each of
which shall be deemed an original, but all of which together shall constitute
one and the same instrument.

Yours very truly,

PREDIX PHARMACEUTICAL HOLDINGS, INC.

/s/ MICHAEL G. KAUFFMAN
-----------------------
Michael G. Kauffman, M.D., Ph.D.
President and CEO

September 24, 2004
------------------
Date

ACCEPTED:

/s/ STEPHEN DONAHUE
---------------------
Dr. Stephen R. Donahue

September 27, 2004
------------------
Date

ADDRESS:
[ADDRESS]

Please sign both originals of this Employment Agreement, keep one copy for your
   files and return a copy to Chris Wang at Predix Pharmaceuticals along with
          completed form # F-CHR002 and a signed copy of the Relocation
                               Payback Agreement.

Enclosures:   Predix Relocation Benefits Policy
              Predix Relocation Payback Agreement
              New Employee Form F-CHR002
<PAGE>

                                   SCHEDULE A

                                   INVENTIONS<PAGE>

(BIOGEN IDEC LOGO)

                              AMENDED OFFER LETTER

Cecil B. Pickett, Ph.D.                                            June 21, 2006

Dear Cecil:

I am pleased to extend to you this offer of employment to join Biogen Idec as
President, Research & Development. This position will report to Jim Mullen,
Chief Executive Officer and President. The position will be based at our
Cambridge, Massachusetts facility.

BASE SALARY: Your starting bi-weekly salary will be $29,807.69, which is
equivalent to an annual salary of $775,000. Consistent with Biogen Idec's
compensation policy, you will be eligible for a merit salary review in early
2007, with anticipated annual reviews thereafter. Your base salary will not be
decreased following future annual salary reviews.

ONE-TIME SIGN-ON BONUS: Upon employment, you will receive $500,000 as a one-time
sign-on bonus. This bonus will be established by the Company on your behalf as a
nonqualified deferred compensation benefit in accordance with the specifications
contained in Attachment A.

SHORT-TERM INCENTIVE: You will be eligible to participate in Biogen Idec's
Annual Bonus Plan, with a target bonus level of 75% of your annualized base
salary. Bonus payments are generally made in March following the year in which
the bonus is earned. In your first year of employment, your Annual Bonus payment
will be prorated based upon your effective date of employment. A copy of the
Annual Bonus Plan document, with references to specific performance targets
deleted, is enclosed with this letter.

LONG-TERM INCENTIVE: Your long-term incentive (LTI) program will consist of
three different awards. These LTI awards are described in detail below and on
Attachment B.

     1.   You will be granted 44,400 restricted stock units (RSUs) which,
          assuming your continued employment, will vest and convert into shares
          of Biogen Idec common stock at the rate of one-third per year for
          three years, beginning on the first anniversary of your grant date.
          The grant date will be the first trading day of the month following
          your first day of employment (i.e., your effective date of
          employment).

     2.   You will also be granted 120,000 RSUs which, assuming your continued
          employment, will vest and convert into shares of Biogen Idec common
          stock at the rate of one-fourth per year for four years, beginning on
          the first anniversary of your grant date. The grant date will be the
          first trading day of the month following your effective date of
          employment.

     3.   Lastly, you will be granted 120,000 performance-based RSUs whose
          vesting will be pursuant to certain performance criteria and continued
          employment through the applicable vesting dates (which would occur
          over the four-year service period beginning with the effective date of
          grant). The formal plan design for this award is still under
          development. A proposed model of this plan is attached for
          illustrative purposes at the end of this letter (Attachment B). Before
          finalizing this plan, we would like to have your involvement in
          establishing the metrics and associated goals upon which performance
          will be measured and rewarded. The final plan design, including the
          performance goals and vesting schedule, is subject to approval by the
          Compensation and Management Development Committee. The effective date
          of grant for these performance-based RSUs will be the date of formal
          Committee approval.

                                                                      Req # 4965

BIOGEN IDEC 14 Cambridge Center Cambridge, MA 02142 Phone 617 679 2000
www.biogenidec.com

<PAGE>

Cecil B. Pickett, Ph.D.
Page 2
June 21, 2006

At the discretion of the Compensation and Management Development Committee, you
will be eligible to receive additional LTI grants over the course of your
employment with Biogen Idec. The actual terms of each of your LTI awards will be
communicated to you in a separate Notice of Grant. You are considered a
"designated employee", as defined in the 2005 Omnibus Equity Plan. Please read
the enclosed 2005 Omnibus Equity Plan Document for information on the
implications of being a designated employee under the Plan, as well as any
applicable terms and conditions of your grants under this program.

STOCK TRADING PLAN: As an executive officer of the Company, you are required to
enter into a 10b5-1 stock trading plan. A 10b5-1 plan enables you to buy and
sell Biogen Idec securities under pre-specified conditions (e.g., when the price
of Biogen Idec stock reaches a certain price), and allows you to sell outside of
quarterly "trading windows" whether or not you are in possession of material,
nonpublic information. A copy of Biogen Idec's 10b5-1 trading policy is enclosed
with this letter.

RELOCATION: Biogen Idec will provide a relocation package to facilitate your
move to the Cambridge, Massachusetts area. A copy of Biogen Idec's relocation
policy is enclosed with this letter. The relocation benefits and payments will
be provided to you after you sign an agreement (Attachment C) that describes in
detail your repayment obligation. Certain payments and/or reimbursements from
Biogen Idec for relocation and housing will become taxable income to you. For
job-related moves, payroll taxes will be withheld for all expenses that are not
directly related to the move, which are defined as non-qualified moving expenses
under State and Federal tax law. You will be responsible for all tax liabilities
incurred for these non-qualified moving expenses.

EMPLOYEE BENEFITS: Biogen Idec offers a robust and highly competitive employee
benefits program. As an employee, you will be able to choose from a menu of
options through our flexible benefits program. These benefits include a 401 (k)
savings plan; group health care, including medical, dental, prescription and
vision coverage; life, dependent life and disability insurance; as well as
flexible spending accounts for eligible medical and dependent care expenses. You
are also entitled to 20 vacation days per year, accrued on a per pay period
basis. Additional benefit offerings include an Employee Stock Purchase Plan
(ESPP) and commuter benefits such as free parking or commuter/rail passes.
Please visit Biogen Idec's benefits website (www.mybenerqy.com; user ID =
cambridge, password = biogen) to familiarize yourself with Biogen Idec's
complete benefit plan offerings.

ADDITIONAL EXECUTIVE BENEFITS

     SUPPLEMENTAL SAVINGS PLAN: You will be entitled to participate in Biogen
     Idec's Supplemental Savings Plan (SSP). This plan allows you to make
     pre-tax deferrals of up to 80% of your base salary and up to 100% of your
     Annual Bonus payment. Your contributions to this plan may be limited by
     your contributions towards other plans (e.g., 401k, ESPP, medical, etc.).

     LIFE INSURANCE: You will be provided life insurance coverage equal to three
     times your annual base salary, to a maximum benefit of $1,500,000, subject
     to meeting the medical standards stated in the group term life insurance
     policy for U.S. employees. Biogen Idec pays the premium for this insurance.
     The IRS requires employers to impute the value of company-paid life
     insurance for coverage over $50,000. This imputed income will be displayed
     on your pay stub.

     SEVERANCE: In the event Biogen Idec terminates your employment other than
     For Cause (as defined in Attachment D), you will receive a severance
     benefit that includes: (i) a cash payment that is calculated based on your
     annual cash compensation; and (ii) coverage under Biogen Idec's group
     medical and dental insurance plans. Your cash severance benefit will be
     based on the lesser of 21 months or the number of months (prorated) between
     the effective date of termination and the date on which you reach age 65.
     Your severance benefits are explained in detail in the attached executive
     severance document (Attachment D).

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 3
June 21, 2006

     IRC 280G EXCISE TAXES: In the event of a Change in Control (as defined in
     Section 280g of the Internal Revenue Code), compensation paid to you may
     trigger an excise tax (in addition to ordinary income taxes). Biogen Idec
     will reimburse you for any excise taxes you incur as a result of a Change
     in Control. This includes gains from the exercise of stock options and
     vesting of restricted stock and/or units, as well as the reimbursement for
     such penalties. In addition, Biogen Idec will reimburse you for income
     taxes imposed on the excise taxes.

     TAX PREPARATION, FINANCIAL AND ESTATE PLANNING: You are entitled to
     reimbursement of up to $7,500 per calendar year (January 1 - December 31)
     for expenses incurred due to tax preparation, financial and/or estate
     planning services, as well as the purchase of tax preparation and/or
     financial planning software. You will be eligible for the full
     calendar-year benefit in the year you begin employment with Biogen Idec.
     Eligible services provided by qualified providers, accompanied by copies of
     receipts/invoices, will be reimbursed. Such reimbursements are considered
     taxable income.

     DIRECTORS & OFFICERS (D&O) INSURANCE: As an executive officer, you will
     automatically be covered by Biogen Idec's standard D&O insurance policy. A
     copy of this policy is enclosed with this letter.

     AIR TRAVEL UPGRADE: You are entitled to fly first class on all U.S.
     transcontinental flights (e.g., Boston to San Diego). Overseas flights and
     other domestic flights are subject to the same policy as all other
     employees.

Biogen Idec will reimburse you for legal fees associated with the initial review
of and the June 1, 2006 response memo to our original May 18, 2006 offer of
employment; any additional fees incurred after June 1, 2006 in regards to legal
review of this employment offer will be your responsibility. Subsequent to your
employment date, any legal fees incurred in connection with a suit commenced by
you to enforce the terms of this employment offer will be reimbursed by the
Company only if you prevail in such suit. Prior to commencing any suit regarding
a potential breach of the terms of this offer by the Company, the Company shall
be provided written notice and an opportunity to cure the potential breach.
Eligible legal fees must be for services provided by qualified legal advisors
and must be accompanied by original detailed invoices. Such reimbursements are
considered taxable income.

Employment with Biogen Idec is contingent on the satisfactory completion of a
drug test. Please see Attachment E (ACTIONS REQUIRED IN ORDER TO BEGIN
EMPLOYMENT) for information about our post-employment offer drug-testing
program. You may also be required to complete a medical history review with our
Occupational Health Department. If required, this review will be scheduled after
your first day of employment.

Biogen Idec requires that all new employees be subject to a background check.
This background check includes verification of employment history, educational
and professional licenses, degrees, and/or credentials, a criminal records
check, a Social Security number search, and verification of any degrees and
other professional qualifications that your position responsibilities at Biogen
Idec may warrant. When you complete your online Application for Employment (see
below), you will be authorizing Biogen Idec to conduct these background checks.
If you have any questions about the background check, please contact me for
additional details.

Please complete the online "Application for Employment" and "Invitation to Self
Identify" forms located at the following website:
http://biogen.biogenidec.com/candidate/. On the Application of Employment, you
will be prompted to enter an "Application Station Code". The code to enter is
BGNDV01 (note: the last two characters are 'zero' one).

In order to protect Biogen Idec's substantial investment of time and money in
the creation and maintaining of its confidential and proprietary information and
good-will with its customers, vendors and other business partners, as a
condition of employment you will be required to sign our Employee Proprietary
Information and Inventions and Dispute Resolution Agreement on your first day of
employment. A copy of the Agreement is enclosed with this letter.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 4
June 21, 2006

The Federal government requires you to provide proper identification verifying
your eligibility to work in the U.S. Please bring the appropriate
identification, including your Social Security card (for number verification
purposes), with you on your effective date of employment.

Please be advised that this offer will remain open through close of business on
June 28, 2006, after which time it will be withdrawn and terminated if you have
not accepted it.

Please confirm your acceptance of this offer of employment by signing this
letter. Please also sign the enclosed drug screen authorization form and return
both signed documents to Biogen Idec in the enclosed self-addressed, stamped
envelope. The other copy of this letter is for your records.

We are very excited about the prospect of you joining Biogen Idec, and encourage
you to accept this offer of employment. You and Jim Mullen can together set your
effective date of employment.

Best regards,

/s/ Craig Eric Schneier
-----------------------------------------
Craig Eric Schneier, Ph.D.
Executive Vice President, Human Resources

cc: Jim Mullen
    Mike Thomas

Your employment at Biogen Idec is employment at-will. This means that just as
you are free to leave your employment at any time, with or without cause or
notice, Biogen Idec also has the same right to terminate your employment at any
time, with or without cause or notice.

I accept this offer of employment and acknowledge the contingencies of
employment described above, including the at-will nature of my employment.

ACCEPTED:

/s/ Cecil B. Pickett                 6/26/06                          9/5/06
--------------------------------------------------------------------------------
Cecil B. Pickett, Ph.D.              Signature Date                  Start Date*

*    Your employment is subject to Biogen Idec receiving negative results (i.e.,
     no drugs found) from your drug test. If you have not received confirmation
     of your test results from Human Resources within a week prior to your start
     date, please contact me to confirm your test results prior to starting.
     Your effective date of employment must be a Monday (unless it is a holiday,
     in which case your start date will be the following Tuesday). Please notify
     me as soon as possible as to the Monday you can begin your employment, and
     indicate this date in the noted area above. Your effective date of
     employment must be on or before September 5, 2006.

NOTE: See the notice titled "ACTIONS REQUIRED IN ORDER TO BEGIN EMPLOYMENT"
attached to this letter for additional actions required to begin employment and
certain other information associated with this offer of employment.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 5
June 21, 2006

                                  ATTACHMENT A

                 ONE-TIME SIGN-ON BONUS: CECIL B. PICKETT, PH.D.

1.   Deferred Compensation Amount. The initial Deferred Compensation Amount
     credited will be $500,000, with Credited Interest from the date of your
     employment by the Company to the date of payment to Cecil B. Pickett, Ph.D.
     (the "Executive") or his Beneficiary.

     Credited Interest will be deemed compound interest earned on the initial
     amount as if it were invested in the Fixed Income Option under the Biogen
     Idec Inc. Supplemental Savings Plan (the "Supplemental Savings Plan") from
     time to time.

2.   Benefit Amount. The Benefit Amount payable to the Executive (or
     Beneficiary) at any time will be the Executive's Deferred Compensation
     Amount at such time multiplied by his vested percentage at such time.

     The Executive's vested percentage at any time will be determined under the
     following table based upon his number of Years of Service at such time:

<TABLE>
<CAPTION>
          Years of Service   Vested Percentage
          ----------------   ------------------
<S>                          <C>
          Less than one             0
          One or more               100%
</TABLE>

     Notwithstanding the foregoing, the Executive will become fully vested in
     the Benefit Amount if he is terminated by the Company (or a subsidiary or
     other affiliate) for reasons other than For Cause (as defined below),
     including termination due to disability, death or without cause. The
     Executive also becomes fully vested in the event of a Change in Control of
     the Company (as defined in the 2005 Omnibus Equity Plan).

     If the Executive terminates employment with the Company (or a subsidiary or
     other affiliate) under circumstances such that he is not fully vested
     (e.g., he voluntarily terminates his employment or is terminated For
     Cause), the non-vested portion of the Benefit Amount as of the date of
     termination of employment will be forfeited and cancelled.

3.   Distribution Events and Timing of Distributions.

          (a)  Unforeseeable Emergency. If the Executive incurs an Unforeseeable
               Emergency, he may request a distribution of an amount specified
               by him, up to a maximum equal to his vested Benefit Amount at
               such time or the amount reasonably needed to alleviate the
               Unforeseeable Emergency (including income taxes and penalties
               reasonably anticipated to be owed as a result of such
               distribution). Any such distribution will be subject to the
               approval of the Retirement Committee, both as to the existence of
               an Unforeseeable Emergency and the amount to be distributed, if
               any.

               A distribution on account of Unforeseeable Emergency will be made
               in a single payment following the Retirement Committee's approval
               of such distribution.

          (b)  Death. In the event of the death of the Executive before the
               complete distribution of his vested Benefit Amount, his
               Beneficiary will receive the balance of his vested Benefit
               Amount.

               The Executive may designate one or more Beneficiaries and may
               revoke or change such a designation at any time. Any such
               designation, revocation or change must be in writing filed with
               the Retirement Committee. Any portion of the vested Benefit
               Amount payable upon the death of the Executive, but not disposed
               of by a designation of Beneficiary, will

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 6
June 21, 2006

               be paid to the Executive's spouse if living at his death,
               otherwise to the Executive's estate.

               A distribution on account of the Executive's death will be made
               in a single payment following the Retirement Committee's receipt
               of appropriate evidence of the Executive's death and of the right
               of any Beneficiary to receive such payment.

          (c)  Termination of Employment. Upon termination of the Executive's
               employment by the Company (and all of its subsidiaries and other
               affiliates), the Executive will receive distribution of his
               vested Benefit Amount (based upon the vested percentage as of the
               date of termination), payable in a lump sum. The payment will be
               made on the first day of the month next following the six-month
               anniversary of the Executive's date of termination of employment.

               The Executive may make one change in the timing or form of
               payment under the preceding paragraph, provided that no such
               change may operate to accelerate any payment or violate any
               requirement of Internal Revenue Code ("Code") Section 409A or the
               regulations and rulings thereunder, including the following
               requirements:

               (i)  The Executive must make such change of election at least 12
                    months before the scheduled date for the first installment
                    payment (in other words, such an election will become
                    effective only if the Executive remains an employee of the
                    Company or a subsidiary or other affiliate during the 12
                    months following the date of the change), and

               (ii) The election extends the date for payment or the start date
                    for installment payments by at least five years.

4.   Miscellaneous.

          (a)  Unfunded Arrangement. This deferred compensation arrangement is
               unfunded and the Executive will not have any rights to any
               specific assets of the Company. The rights of the Executive (or
               any Beneficiary) are solely those of an unsecured, general
               creditor of the Company.

               Notwithstanding the preceding paragraph, the Company may
               establish or contribute to an existing grantor trust to assist it
               in the provision of benefits hereunder, provided that no such
               trust is intended to cause this arrangement to be considered
               "funded" for purposes of Title of the Employee Retirement Income
               Security Act of 1974, as amended.

          (b)  No Assignment. The Executive (or Beneficiary) will have no power
               or right to transfer, assign, anticipate or otherwise encumber
               his deferred compensation benefits hereunder, and no such benefit
               will be payable to or subject to seizure or attachment by any
               creditor of the Executive (or Beneficiary), except as required by
               law.

          (c)  Tax Withholding. All distributions or payments hereunder to any
               person are subject to the withholding of income and other taxes
               to the extent required by law.

          (d)  Definitions of Terms. The following terms are defined or
               explained in the Supplemental Savings Plan and have the same
               meaning when used herein: Fixed Income Option, Year of Service,
               Disability, Unforeseeable Emergency and Termination of
               Employment. The Retirement Committee that administers the
               Supplemental Savings Plan will also administer the deferred
               compensation benefit hereunder.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 7
June 21, 2006

               For purposes of this Benefit Amount, termination by the Company
               For Cause means any of the following: (A) the Executive's
               conviction by a court of competent jurisdiction for felony
               criminal conduct; (B) the Executive's gross negligence or willful
               misconduct (unless he believed in good faith that the act or
               omission was in or not opposed to the interest of the Company
               (without intent on the Executive's part to gain therefrom,
               directly or indirectly, a profit to which he was not legally
               entitled)), in either case in the performance of the Executive's
               duties hereunder that results in a detriment that is material to
               the Company and its subsidiaries taken as a whole; or (C) the
               Executive's willful or intentional material breach of agreements
               regarding competing with the Company during or subsequent to
               employment with the Company, or of the Executive's Proprietary
               Information and Inventions Agreement that results in detriment
               that is material to the Company and its subsidiaries as a whole.
               Notwithstanding the foregoing, Cause shall not include any act or
               omission of which the Finance and Audit Committee of the Board
               (or the full Board) has had actual knowledge for at least six
               months without asserting that the act or omission constitutes
               Cause.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 8
June 21, 2006

                                  ATTACHMENT B

    PERFORMANCE-BASED RESTRICTED STOCK UNIT PROGRAM: CECIL B. PICKETT, PH.D.
                               (ILLUSTRATION ONLY)

<TABLE>
<CAPTION>
                                                                PERFORMANCE SCORECARD METRICS (1)
                               -----------------------------------------------------------------------------------------------------
                      TOTAL          FINANCIAL                                                                      ORGANIZATIONAL
   PERFORMANCE     POTENTIAL   (25% weight; 30,000           DEVELOPMENT                RESEARCH (PIPELINE)          (25% weight;
      PERIOD       SHARE VEST         shares)        (25% weight; 30,000 shares)    (25% weight, 30,000 shares)     30,000 shares)
   -----------     ----------  -------------------  -----------------------------  -----------------------------  ------------------
<S>                <C>         <C>                  <C>                            <C>                            <C>
10/1/2006 through     30,000   Threshold EPS        Ensure at least ____ NMEs/     Advance at least_______        Develop and gain
   12/31/2007                  attainment (50%      _____ NCEs enter pipeline, at  research products into         CEO/BOD approval
                               weight)              phase 2 or later stage,        development by________(50%     of EVP, R&D
                                                    resulting in___% increase in   weight)                        successor, based
                               Threshold Revenue    forecasted 2010-2015 revenue                                  on pre-
                               attainment           CAGR                           Advance________ proof-of-      established
                               (50% weight)                                        concept products into pivotal  criteria/
                                                                                   trials by________(50% weight)  milestones
                                                                                                                  (50% weight)

                                                                                                                  Develop and gain
                                                                                                                  approval of 5-
                                                                                                                  year R&D
                                                                                                                  strategic plan
                                                                                                                  (50% weight)

1/1/2008 through      30,000            TBD                       TBD                            TBD                      TBD
   12/31/2008

1/1/2009 through      30,000            TBD                       TBD                            TBD                      TBD
   12/31/2009

                      30,000            TBD                       TBD                            TBD                      TBD

                     120,000          30,000                    30,000                         30,000                   30,000
</TABLE>

(1)  Awards not earned in a particular year are canceled (do not carry over to
     subsequent years).

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 9
June 21, 2006

                                  ATTACHMENT C

                        BIOGEN IDEC RELOCATION AGREEMENT

This document will serve to acknowledge that I have accepted a position of
employment from Biogen Idec, which will involve the relocation of my residence.
Biogen Idec is willing to pay on my behalf, or reimburse me for, certain
expenses that may be incurred in connection with such relocation, so long as I
remain an employee of Biogen Idec for at least two years. I hereby accept Biogen
Idec's offer of assistance as follows:

I acknowledge that Biogen Idec's agreement to pay on my behalf, or reimburse me
for, certain expenses, which may be incurred in relocating my residence,
including the nature and the amount, and the timing and method of such payment
or reimbursement, shall be in accordance with Biogen Idec's relocation policies
and procedures in effect at the time of my relocation.

Certain payments/reimbursements from Biogen Idec for relocation and housing will
become taxable income to me.

If I voluntarily terminate my employment for reasons other than those described
below, or Biogen Idec terminates my employment For Cause as described below,
repayment will be required according to the following schedule: (i) if my
employment terminates on or before the first anniversary of my date of hire, the
full dollar amount of the relocation package I received must be repaid to the
Company, or (ii) if my employment terminates on or before the second anniversary
of my date of hire, half of the dollar amount of the relocation package I
received must be repaid to the Company.

I shall pay to Biogen Idec all such amounts within thirty days of the effective
date of termination of employment with Biogen Idec or by year-end, whichever
comes first. Biogen Idec may deduct, withhold and retain all or any portion of
the amount which I may be required to refund or repay to Biogen Idec hereunder
from any wages, salary, vacation pay or severance pay which may be due and owing
to me upon termination of employment. I shall remain liable to Biogen Idec for
any amounts in excess of the sums so deducted, withheld and retained by Biogen
Idec.

If I terminate my employment as a result of: (A) any material diminution in my
duties, position, authority or reporting relationship that occurs within two
years of my effective date of employment; (B) I cease to be a member of the
Board of Directors due to not being nominated for election or re-election; (C)
any reduction in my base salary or target bonus opportunity; (D) any relocation
of the Company's principal executive offices which increases my daily commute by
more than 100 miles on a round trip basis; or (E) breach of any material
obligation of the Company under the offer letter which is not promptly cured
after written notice, no repayment of relocation benefits will be required.

For purposes of this relocation benefit, termination by the Company For Cause
means any of the following: (A) my conviction by a court of competent
jurisdiction for felony criminal conduct; (B) my gross negligence or willful
misconduct (unless I believed in good faith that the act or omission was in or
not opposed to the interest of the Company (without intent on my part to gain
therefrom, directly or indirectly, a profit to which I was not legally
entitled)), in either case in the performance of my duties hereunder that
results in a detriment that is material to the Company and its subsidiaries
taken as a whole; or (C) my willful or intentional material breach of agreements
regarding competing with the Company during or subsequent to employment with the
Company, or of my Proprietary Information and Inventions Agreement that results
in detriment that is material to the Company and its subsidiaries as a whole.
Notwithstanding the foregoing, Cause shall not include any act or omission of
which the Finance and Audit Committee of the Board (or the full Board) has had
actual knowledge for at least six months without asserting that the act or
omission constitutes Cause.

If, after incurring relocation expenses I reject the previously accepted offer
of employment, I agree to repay Biogen idec all expenses within 10 days of
notification of the amounts owed.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 10
June 21, 2006

Except as stated above, I shall have no liability or responsibility to refund or
repay to Biogen Idec any amounts paid by Biogen Idec on my behalf or reimbursed
to me in connection with the relocation of my residence.

My signature below acknowledges that I have read this document and agree to its
terms.

Cecil B. Pickett
-------------------------------------   ----------------------------------------
Employee Name (Please Print)            Social Security Number

/s/ Cecil B. Pickett                    6/26/06
-------------------------------------   ----------------------------------------
Employee Signature                      Date

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 11
June 21, 2006

                                  ATTACHMENT D

                           EXECUTIVE SEVERANCE BENEFIT

You are entitled to severance benefits in the event your employment is
terminated by Biogen Idec other than For Cause (as defined below), or if you
terminate your employment as a result of: (A) any material diminution in your
duties, position, authority or reporting relationship that occurs within two
years of your effective date of employment; (B) you cease to be a member of the
Board of Directors due to not being nominated for election or re-election; (C)
any reduction in your base salary or target bonus opportunity; (D) any
relocation of the Company's principal executive offices which increases your
daily commute by more than 100 miles on a round trip basis; or (E) breach of any
material obligation of the Company under the offer letter which is not promptly
cured after written notice.

Definition of "For Cause." Termination by the Company For Cause means any of the
following: (A) your conviction by a court of competent jurisdiction for felony
criminal conduct; (B) your gross negligence or willful misconduct (unless you
believed in good faith that the act or omission was in or not opposed to the
interest of the Company (without intent on your part to gain therefrom, directly
or indirectly, a profit to which you were not legally entitled)), in either case
in the performance of your duties hereunder that results in a detriment that is
material to the Company and its subsidiaries taken as a whole; or (C) your
willful or intentional material breach of agreements regarding competing with
the Company during or subsequent to employment with the Company, or of your
Proprietary Information and Inventions Agreement that results in detriment that
is material to the Company and its subsidiaries as a whole. Notwithstanding the
foregoing, Cause shall not include any act or omission of which the Finance and
Audit Committee of the Board (or the full Board) has had actual knowledge for at
least six months without asserting that the act or omission constitutes Cause.

Your severance benefits will be comprised of (i) a lump sum payment (as
calculated below) and (ii) upon completion of the appropriate forms,
continuation of your participation in Biogen Idec's group medical and dental
insurance plans, to the same extent permitted by COBRA and to the same extent
such insurance is then provided to regular employees of Biogen Idec, including
payment by you of a portion of the insurance premiums (i.e., the "Insurance
Benefit").

The lump sum severance payment will be the lesser of 21 months and the number of
months (prorated) between the effective date of termination and date on which
you reach age 65, multiplied by the monthly equivalent of your target annual
cash compensation at the time of your termination (i.e., one-twelfth of the sum
of your then annual base salary plus target annual bonus).

The lump sum payment (less applicable taxes and other mandatory deductions as
required by law) will be paid to you promptly following the later of (i) the
termination of your employment with Biogen Idec and (ii) the effective date of a
signed general release in favor of Biogen Idec (see below). The Insurance
Benefit will continue until the earlier of (i) the date you become eligible to
participate in the medical and dental insurance plan of a third party employer,
(ii) the last day of the 21st month following the termination of your employment
with Biogen Idec, or (iii) the last day of the month in which you reach age 65
(the "Insurance Benefit Period").

The following are examples of how the lump sum payment and Insurance Benefit
Period are determined:

     If your employment with Biogen Idec is terminated and the amount of time
     between your effective date of termination and the date you reach age 65 is
     equal to or greater than 21 months, you will receive a lump sum payment
     equal to 21 months of your annualized target cash compensation and continue
     to participate in Biogen Idec's group medical and dental plans for 21
     months, unless you become eligible to participate in another employer's
     medical and dental plans before that date.

     If your employment with Biogen Idec is terminated and the amount of time
     between your effective date of termination and the date you reach age 65 is
     six and one-half months, you will receive a lump sum payment equal to six
     and one-half months of your annualized target cash compensation and
     continue to

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 12
June 21, 2006

     participate in Biogen Idec's group medical and dental plans through the
     last day of the month in which you reach age 65, unless you become eligible
     to participate in another employer's medical and dental plans before that
     date.

If required under Code Section 409A, a delay of six months may apply to any
severance payment.

In addition, should the Company terminate your employment other than For Cause,
you will be entitled to receive up to nine months of executive-level
outplacement services, at the expense of Biogen Idec, from a recognized provider
of such services chosen by Biogen Idec.

If at any time within two years following a Corporate Transaction or Corporate
Change in Control (as such terms are defined in Biogen Idec's 2005 Omnibus
Equity Plan) your employment is terminated by Biogen Idec or the succeeding
corporate entity, other than For Cause (as such term is defined above), or you
experience an Involuntary Employment Action (referred to below) and as a result
you terminate your employment with Biogen Idec or the succeeding corporate
entity, then, regardless of the length of your service with Biogen Idec and the
succeeding corporate entity, and in lieu of the formula set forth above, you
will receive a lump sum payment equivalent to 24 months of your then annual base
salary and target annual bonus. In addition, you will be entitled to continue
participating in Biogen Idec's group medical and dental plans for 24 months,
unless you reach age 65 or become eligible to participate in another employer's
medical and dental plans before that date. The term "Involuntary Employment
Action" shall have the definition set forth in Biogen Idec's 2005 Omnibus Equity
Plan, provided, however, that the term "Corporate Transaction" used in such
definition shall be deemed to mean either a corporate transaction or change in
control, as the case may be.

Payment and provision of the severance benefits described above are conditioned
on your execution of a general release in favor of Biogen Idec, in form and
substance reasonably acceptable to Biogen Idec, in respect to any and all claims
relating to your employment and the termination of your employment with Biogen
Idec. If you retire or voluntarily terminate your employment with Biogen Idec,
or Biogen Idec terminates your employment For Cause (as such term is defined in
Biogen Idec's 2005 Omnibus Equity Plan), or you do not provide the requisite
general release, you will not be eligible to receive the severance benefits
described above.

                                                                      Req # 4965

<PAGE>

Cecil B. Pickett, Ph.D.
Page 13
June 21, 2006

                                  ATTACHMENT E

                  ACTIONS REQUIRED IN ORDER TO BEGIN EMPLOYMENT

You are covered by Biogen Idec's benefits the first day you are actively at
work, but we need information to make sure our benefit providers and Payroll
department know who you are.

Upon your acceptance of Biogen Idec's offer of employment, please visit our
Company website, www.biogenidec.com. Under "Careers", select "More". On the
right-hand side, click "For New Employees". This site contains the forms you
must complete in order to add you to Biogen Idec's Payroll and Human Resources
systems. Completion of these forms is required 7 days prior to your first day of
employment at Biogen Idec. If you will be working outside of Cambridge, Research
Triangle Park or San Diego, please send your forms to Arkia French, 14 Cambridge
Center, Cambridge, MA, 02142. Further instructions are posted on the website
when you log in to complete your forms.

YOUR USERNAME IS YOUR SOCIAL SECURITY NUMBER, AND YOUR PASSWORD

As part of Biogen Idec's employment practices, a drug-screening test is required
to be competed 10 days prior to your first day of employment and we must conduct
a background check. This background check includes verification of employment
history, educational and professional licenses, degrees, and/or credentials, a
criminal records check, a Social Security number search, and verification of any
degrees and other professional qualifications that your position
responsibilities at Biogen Idec may warrant. Your employment is subject to
Biogen Idec's receipt of favorable results of these employment contingencies. If
you have not received your confirmation from Human Resources to report to work,
please contact me to confirm your results prior to starting. Your start day must
be a Monday (unless that is a holiday, in which case your start day will be the
following Tuesday). Please notify me as soon as possible of the Monday you can
start and indicate this date on the signed offer letter you return.

IN ORDER TO BEGIN EMPLOYMENT, YOU MUST:

     -    Complete the Payroll and HR forms described above 7 days in advance of
          your first day of employment.

     -    Complete your drug screen 10 days in advance of your first day of
          employment.

If you are unable to complete the above as outlined, we can reschedule your
start date, as needed.

I or someone else from Human Resources will greet you on your first day at 8:00
a.m. in the lobby of 10 Cambridge Center, Cambridge, MA. You will then be
escorted to Benefits Orientation. If you desire to make other arrangements for
Benefits Orientation, please let me know.

If you plan to park at a Biogen Idec facility on a regular basis, please bring
the license plate number of the vehicle(s) you will be parking at the facility.
Plate numbers are required in order to issue a parking access card.

We are pleased to welcome you to Biogen Idec. If you have any questions, please
contact Mike Thomas (617-679-2038) or me (617-914-4500).

                                                                      Req # 4965

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