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                                                                    EXHIBIT 10.2



VIA HAND DELIVERY

October 9, 2006


Vincent J. Miles, Ph.D.
62 Woodchester Drive
Chestnut Hill, MA 02467

Dear Vin:

This letter agreement sets forth the terms of your continued employment with
Alnylam Pharmaceuticals, Inc. (the "Company"). In the event that the terms of
your offer letter with the Company conflict with the terms hereof, this letter
agreement shall govern.

As we have discussed, it is currently expected that your employment with the
Company will continue on a full time basis through December 31, 2006 and
thereafter on a part time basis until August 1, 2007, at which time your
employment with the Company will terminate. The Company is hereby offering to
provide you with the pay and benefits described in Attachment A hereto, if you
timely sign and return this letter agreement and, on or within three business
days after your Termination Date (as defined below), you sign and return the
release of claims attached hereto as Attachment B and it becomes binding upon
you. Because both this letter agreement and Attachment B will become binding
agreements between you and the Company, you are advised to consult with your
attorney before signing this letter agreement and Attachment B, and you have
been given twenty-one (21) days to do so. If you sign this letter agreement,
and, on or within three business days after the Termination Date, Attachment B,
you may change your mind and revoke your acceptance during the seven (7) day
period after you have signed each of them, by delivering a written notice of
revocation to me at the Company. In the event that you choose not to accept this
offer, or you timely revoke within the seven (7) days after signing each
agreement, your employment will terminate effective immediately, and all
compensation and benefits will terminate immediately.

If, after reviewing this letter agreement and its attachments, you find the
terms and conditions are satisfactory to you, you should sign and return this
letter agreement to me by October 31, 2006 and then sign and return Attachment B
as required herein. The following numbered paragraphs set forth the terms and
conditions which will apply if this letter agreement becomes binding and
Attachment B becomes binding between you and the Company.

1.       TERMINATION DATE - Should you accept this offer, your effective date of
         termination from the Company will be August 1, 2007 (the "Termination
         Date") (the period between the date hereof and August 1, 2007 shall be
         defined as the "Transition Period"). If on or before August 1, 2007,
         you terminate your employment with the Company or the Company
         terminates your employment for "cause" as defined herein, the Company
         will only be obligated to provide you with the pay and benefits earned
         by you through the last day of your employment with the Company. If
         during the Transition Period the Company were to terminate your
         employment without "cause" as defined herein, and provided this
         agreement and Attachment A become binding upon you, (a) the Company
         shall continue to pay you all amounts then unpaid that would otherwise
         be due to you under paragraphs 1 and 2 of Attachment A if the
         Transition Period were to continue until August 1, 2007; (b) the
         Company shall pay, within thirty (30) days of Attachment B becoming
         binding upon you, the amount that would be due to you under paragraph 3
         of Attachment A as though you had been continuously employed as a 50%
         part time employee between January 1, 2007 and August 1, 2007. For
         purposes of this agreement, "cause" shall be defined as a good faith
         finding by the Company of



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         your failure to perform your obligations where such failure will or
         could cause material harm to the Company. In the event that you choose
         not to accept this offer, your employment will terminate, effective
         October 31, 2006, and all compensation and benefits will terminate as
         of that date. As of the Termination Date, all salary payments from the
         Company will cease and any benefits you currently have under
         Company-provided benefit plans, programs, or practices will terminate,
         except as required by federal or state law, or as otherwise described
         herein.

2.       DESCRIPTION OF TRANSITION PAY AND BENEFITS --The pay and benefits which
         will be provided to you if you both timely sign and return this letter
         agreement and timely sign, return and do not revoke the release
         agreement at Attachment B, are described in the "Description of
         Transition Pay and Benefits" attached as Attachment A.

3.       RELEASE - In consideration of the pay and benefits, to which you
         acknowledge you would not otherwise be entitled, you (on behalf of
         yourself, your agents, assignees, attorneys, successors, assigns, heirs
         and executors) hereby fully, forever, irrevocably and unconditionally
         release, remise and discharge the Company, including, but not limited
         to, its affiliates, subsidiaries, parent companies, predecessors and
         successors and all of their respective past and present officers,
         directors, stockholders, corporate affiliates, parents, subsidiaries,
         plan administrators, attorneys, agents, employees, insurers and
         fiduciaries (each in their individual and corporate capacities)
         (collectively, the "Released Parties") from any and all claims,
         charges, complaints, demands, actions, causes of action, suits, rights,
         debts, sums of money, costs, accounts, reckonings, covenants,
         contracts, agreements, promises, doings, omissions, damages,
         executions, obligations, liabilities, and expenses (including
         attorneys' fees and costs), of every kind and nature which you ever had
         or now have against any of the Released Parties, including, but not
         limited to, all employment discrimination claims under Title VII of the
         Civil Rights Act of 1964, 42 U.S.C. Section 2000e et seq., the Age
         Discrimination in Employment Act, 29 U.S.C. Section 621 et seq., the
         Americans With Disabilities Act, 42 U.S.C., Section 12101 et seq., and
         the Rehabilitation Act of 1973, 29 U.S.C. Section 701 et seq., all as
         amended; all claims arising out of the Employment Retirement Income
         Security Act of 1974, 29 U.S.C. Section 1001 et seq., and the Worker
         Adjustment and Retraining Notification Act, 29 U.S.C. Section 2101 et
         seq., all as amended; the Massachusetts Fair Employment Practices Act,
         M.G.L. c. 151B, Section 1 et seq., the Massachusetts Civil Rights Act,
         M.G.L. c. 12, Sections 11H and 11I, the Massachusetts Equal Rights Act,
         c. 93, Section 102 and M.G.L. c. 214, Section 1C, the Massachusetts
         Labor and Industries Act, M.G.L. c. 149, Section 1 et seq., the
         Massachusetts Maternity Leave Act, M.G.L. c. 149, Section 105(d), and
         the Massachusetts Privacy Act, M.G.L. c. 214, Section 1B, all as
         amended; all common law claims including, but not limited to, actions
         in tort, defamation and breach of contract; all claims to any
         non-vested ownership interest in the Company, contractual or otherwise,
         including but not limited to claims to stock or stock options; and any
         claim or damage arising out of your employment with or separation from
         the Company (including any claim for retaliation) under any common law
         theory or any federal, state or local statute or ordinance not
         expressly referenced above; provided, however, that nothing in this
         letter agreement prevents you from filing, cooperating with, or
         participating in any proceeding before the EEOC or a state Fair
         Employment Practices Agency (except that you acknowledge that you may
         not be able to recover any monetary benefits in connection with any
         such claim, charge or proceeding).

4.       NON-DISCLOSURE - You acknowledge your obligation to keep confidential
         all non-public information concerning the Company which you acquired
         during the course of employment with the Company. As stated more fully
         in the Employee Nondisclosure, Noncompetition and Assignment of
         Intellectual Property Agreement signed by you in favor of the Company
         (which remains in full force and effect), you will not disclose any
         such information to, or use such information for, the benefit of any
         third party, including competitors of the Company. You also restate and
         reaffirm all of your other obligations contained in the Employee
         Nondisclosure, Noncompetition and Assignment of Intellectual Property
         Agreement.



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5.       NON-DISPARAGEMENT -- To the extent permitted by law, you understand and
         agree that as a condition for payment to you of the pay and benefits
         herein described, you shall not make any false, disparaging or
         derogatory statements to any media outlet, industry group, financial
         institution or current or former employee, consultant, client or
         customer of the Company regarding the Company or any of the Released
         Parties, or about the Company's business affairs and financial
         condition.

6.       COMPANY PROPERTY - You agree to return to the Company, on the
         Termination Date, all keys, files, records, documents (and any
         electronic copies thereof), equipment (including, but not limited to,
         computer hardware, software and printers, wireless handheld devices,
         cellular phones, pagers, etc.), Company identification, and any other
         Company-owned property in your possession or control and to leave
         intact all electronic Company documents, including but not limited to
         those which you developed or helped develop during your employment. You
         further confirm that you have cancelled all accounts for your benefit,
         if any, in the Company's name, including but not limited to, credit
         cards, telephone charge cards, cellular phone and/or pager accounts and
         computer accounts.

7.       AMENDMENT - This letter agreement shall be binding upon the parties and
         may not be modified in any manner, except by an instrument in writing
         of concurrent or subsequent date signed by duly authorized
         representatives of the parties hereto. This letter agreement is binding
         upon and shall inure to the benefit of the parties and their respective
         agents, assigns, heirs, executors, successors and administrators.

8.       WAIVER OF RIGHTS - No delay or omission by the Company in exercising
         any right under this letter agreement shall operate as a waiver of that
         or any other right. A waiver or consent given by the Company on any one
         occasion shall be effective only in that instance and shall not be
         construed as a bar or waiver of any right on any other occasion.

9.       VALIDITY - Should any provision of this letter agreement be declared or
         be determined by any court of competent jurisdiction to be illegal or
         invalid, the validity of the remaining parts, terms or provisions shall
         not be affected thereby and said illegal and invalid part, term or
         provision shall be deemed not to be a part of this letter agreement.

10.      CONFIDENTIALITY - You understand and agree that as a condition for
         payment to you of the pay and benefits herein described, the terms and
         conditions of this letter agreement, and the contents of any
         negotiations and discussions resulting in this letter agreement, shall
         be maintained as confidential by you and your agents and
         representatives and shall not be disclosed to any third party except to
         the extent required by federal or state law or otherwise agreed to in
         writing by the Company.

11.      NATURE OF AGREEMENT - You understand and agree that this letter
         agreement is a Transition Pay and Benefits agreement and does not
         constitute an admission of liability or wrongdoing on the part of the
         Company.

12.      ACKNOWLEDGMENTS - You acknowledge that you have been given at least
         twenty-one (21) days to consider this letter agreement and its
         Attachment A, and the release of claims at Attachment B, and that the
         Company advised you to consult with an attorney of your own choosing
         prior to signing. You understand that you may revoke this agreement, as
         well as Attachment B, for a period of seven (7) days after you sign the
         respective agreement, and the agreement shall not be effective or
         enforceable until the expiration of each seven (7) day revocation
         period.

13.      VOLUNTARY ASSENT - You affirm that no other promises or agreements of
         any kind have been made to



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         or with you by any person or entity whatsoever to cause you to sign
         this letter agreement, and that you fully understand the meaning and
         intent of this agreement. You state and represent that you have had an
         opportunity to fully discuss and review the terms of this letter
         agreement, including Attachments A and B, with an attorney. You further
         state and represent that you have carefully read this letter agreement,
         including Attachments A and B, understand the contents therein, freely
         and voluntarily assent to all of the terms and conditions thereof, and
         sign your name of your own free act.

14.      APPLICABLE LAW - This letter agreement shall be interpreted and
         construed by the laws of the Commonwealth of Massachusetts, without
         regard to conflict of laws provisions. You hereby irrevocably submit to
         and acknowledge and recognize the jurisdiction of the state and federal
         courts of Massachusetts (which courts, together with all applicable
         appellate courts, for purposes of this letter agreement, are the only
         courts of competent jurisdiction) over any suit, action or other
         proceeding arising out of, under or in connection with this letter
         agreement or the subject matter hereof.

15.      ENTIRE AGREEMENT - This letter agreement, including Attachments A and
         B, contains and constitutes the entire understanding and agreement
         between the parties hereto with respect to your pay and benefits and
         the settlement of claims against the Company and cancels all previous
         oral and written negotiations, agreements, commitments, and writings in
         connection therewith. Nothing in this paragraph, however, shall modify,
         cancel or supersede your obligations set forth in paragraph 4, herein.

Whether or not you accept this offer, upon termination of your employment, you
will receive payment for any unused paid time off accrued through your
termination, and you may elect to continue receiving group medical insurance
pursuant to the federal "COBRA" law, 29 U.S.C. Section 1161 et seq. All premium
costs after termination of your employment shall be paid by you on a monthly
basis for as long as, and to the extent that, you remain eligible for COBRA
continuation. You should consult the COBRA materials to be provided by the
Company.




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If you have any questions about the matters covered in this letter, please
contact me.

Very truly yours,

Alnylam Pharmaceuticals, Inc.


By: /s/ Patricia Allen
    ------------------------------
    Name:  Patricia Allen
    Title: Vice President, Finance


I hereby agree to the terms and conditions set forth above and in the attached
Description of Pay and Benefits. I have been given at least twenty-one (21) days
to consider this agreement and I have chosen to execute this on the date below.
I intend that this letter agreement will become a binding agreement between me
and the Company if I do not revoke my acceptance in seven (7) days. I further
understand that payment to me of the Transition Pay and Benefits described in
Attachment A is conditioned upon my timely execution and return, and
non-revocation of Attachment B.

       /s/ Vincent J. Miles                        October 20, 2006
       ----------------------------                ---------------------------
       Vincent J. Miles, Ph.D.                                Date

To be returned to me by October 31, 2006.





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                                  ATTACHMENT A

                   DESCRIPTION OF TRANSITION PAY AND BENEFITS


During the Transition Period, the additional pay and benefits which will be
provided to you if you timely sign and return the letter agreement and it
becomes binding, unless you terminate your employment with the Company or the
Company terminates your employment for "cause" as defined in the letter
agreement to which this Attachment is attached, are as follows:

     1.  Until December 31, 2006, you will continue as a full time employee at
         your current salary, enjoying all of your current benefits, and also
         will be eligible for a bonus under Alnylam's 2006 Bonus Program in
         accordance with the terms of the program.

     2.  Between January 1, 2007 and August 1, 2007, you will work only 50% of
         your full time schedule and as such shall receive only 50% of your
         current base salary, which shall equal $5,240.23 per regular
         semi-monthly pay period, less applicable taxes and withholdings. During
         this period, subject to your continued employment with the Company, you
         will continue to enjoy the following benefits provided by the Company:
         time off for company holidays; continued vesting of your stock options;
         and vacation time, which vacation time shall accrue at a rate of 5
         hours per month. As you will not be eligible for any medical and dental
         coverage, you may elect to continue receiving group medical and dental
         insurance pursuant to the federal "COBRA" law, 29 U.S.C. Section 1161
         et seq., and should consult the COBRA materials to be provided by the
         Company for details regarding these benefits. In the event that you
         make such a timely election, during the Transition Period, the Company
         will reimburse you for any difference between the premiums you are
         required to pay for such COBRA coverage and the premiums that you would
         pay if you were still an eligible employee covered by the Company's
         group medical and dental plan. After your Termination Date, you will no
         longer be eligible to receive reimbursement for the difference in
         premiums.


If after the Termination Date you timely sign, return and do not revoke the
release agreement Attachment B, you also will receive the following additional
payment:

     3.  A lump sum cash payment in an amount equal to (1) $1,122.91 multiplied
         by (2) the number of full weeks that you remain employed by the Company
         as a 50% part time employee during the period beginning on January 1,
         2007 and ending on August 1, 2007, less all applicable taxes and
         withholdings. Such payment will be made within thirty (30) days of
         Attachment B becoming binding upon you.






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                                  ATTACHMENT B

                                RELEASE OF CLAIMS

RELEASE - In consideration of the pay and benefits described on Attachment A, to
which you acknowledge you would not otherwise be entitled, you (on behalf of
yourself, your agents, assignees, attorneys, successors, assigns, heirs and
executors) hereby fully, forever, irrevocably and unconditionally release,
remise and discharge the Company, including, but not limited to, its affiliates,
subsidiaries, parent companies, predecessors and successors and all of their
respective past and present officers, directors, stockholders, corporate
affiliates, parents, subsidiaries, plan administrators, attorneys, agents,
employees, insurers and fiduciaries (each in their individual and corporate
capacities) (collectively, the "Released Parties") from any and all claims,
charges, complaints, demands, actions, causes of action, suits, rights, debts,
sums of money, costs, accounts, reckonings, covenants, contracts, agreements,
promises, doings, omissions, damages, executions, obligations, liabilities, and
expenses (including attorneys' fees and costs), of every kind and nature which
you ever had or now have against any of the Released Parties, including, but not
limited to, all employment discrimination claims under Title VII of the Civil
Rights Act of 1964, 42 U.S.C. Section 2000e et seq., the Age Discrimination in
Employment Act, 29 U.S.C. Section 621 et seq., the Americans With Disabilities
Act, 42 U.S.C., Section 12101 et seq., the Family and Medical Leave Act, 29
U.S.C. Section 2601 et seq., and the Rehabilitation Act of 1973, 29 U.S.C.
Section 701 et seq., all as amended; all claims arising out of the Employment
Retirement Income Security Act of 1974, 29 U.S.C. Section 1001 et seq., and the
Worker Adjustment and Retraining Notification Act, 29 U.S.C. Section 2101 et
seq., all as amended; the Massachusetts Fair Employment Practices Act, M.G.L. c.
151B, Section 1 et seq., the Massachusetts Civil Rights Act, M.G.L. c. 12,
Sections 11H and 11I, the Massachusetts Equal Rights Act, c. 93, Section 102 and
M.G.L. c. 214, Section 1C, the Massachusetts Labor and Industries Act, M.G.L. c.
149, Section 1 et seq., the Massachusetts Maternity Leave Act, M.G.L. c. 149,
Section 105(d), and the Massachusetts Privacy Act, M.G.L. c. 214, Section 1B,
all as amended; all common law claims including, but not limited to, actions in
tort, defamation and breach of contract; all claims to any non-vested ownership
interest in the Company, contractual or otherwise, including but not limited to
claims to stock or stock options; and any claim or damage arising out of your
employment with or separation from the Company (including any claim for
retaliation) under any common law theory or any federal, state or local statute
or ordinance not expressly referenced above; provided, however, that nothing in
this letter agreement prevents you from filing, cooperating with, or
participating in any proceeding before the EEOC or a state Fair Employment
Practices Agency (except that you acknowledge that you may not be able to
recover any monetary benefits in connection with any such claim, charge or
proceeding).

You hereby acknowledge that you have been given at least twenty-one (21) days to
consider this Attachment B, and that the Company advised you to consult with any
attorney of your own choosing prior to signing this Attachment B. You may revoke
your acceptance of this Attachment B during the period of seven (7) days after
the execution of it, and this Attachment B shall not become effective or
enforceable, and no Transition Pay and Benefits payments will be made pursuant
to Attachment A, until this seven (7) day period has expired.

You further affirm that you have returned all Company property as provided in
Paragraph 6 of the letter agreement.



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         I hereby provide this release of claims as of the current date and
         acknowledge that the execution of this Attachment B is in further
         consideration of the compensation benefits set forth in Attachment A to
         the letter agreement, to which I acknowledge I would not be entitled if
         I did not sign this release of claims.


         ------------------------------         -------------------------
         Vincent J. Miles, Ph.D.                          Date

To be signed and returned to Patricia Allen on or within three days after the
Termination Date.




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