Washington, D.C. 20549


Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB Number: 3235-0104
Estimated average burden
hours per response: 0.5
1. Name and Address of Reporting Person*
Poulton Jeffrey V.

(Last) (First) (Middle)


(City) (State) (Zip)
2. Date of Event Requiring Statement (Month/Day/Year)
3. Issuer Name and Ticker or Trading Symbol
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
Chief Financial Officer
5. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)
Table II - Derivative Securities Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4) 2. Date Exercisable and Expiration Date (Month/Day/Year) 3. Title and Amount of Securities Underlying Derivative Security (Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 6. Nature of Indirect Beneficial Ownership (Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) (1) 07/31/2029 Common Stock 125,000 75.36 D
Explanation of Responses:
1. The stock option vests as to 25% of the shares on the 1st anniversary of the date of the stock option grant and as to an additional 6.25% of the shares each successive three month period thereafter.
By: /s/ Mary Beth DeLena, Attorney-in-Fact For: Jeffrey V. Poulton 08/13/2019
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

Know all of these presents, that the undersigned hereby 
revokes and nullifies any prior power of attorney for Section 
16 reporting obligations, and makes, constitutes and appoints 
each of Laurie Keating, Mary Beth DeLena and Cindy Anderson, 
signing singly and each acting individually, as the 
undersigneds true and lawful attorney-in-fact with full power 
and authority as hereinafter described to:

(1) execute for and on behalf of the undersigned, in the 
Undersigneds capacity as an officer and/or director of Alnylam 
Pharmaceuticals, Inc. (the Company), Forms 3, 4 and 5 
(including any amendments thereto) in accordance with Section 
16(a) of the Securities and Exchange Act of 1934, as amended, 
and the rules thereunder (the Exchange Act);

(2) do and perform any and all acts for and on behalf of the 
undersigned which may be necessary or desirable to prepare, 
complete and execute any such Form 3, 4, or 5, prepare, complete 
and execute any amendment or amendments thereto, and timely 
deliver and file such form with the United States Security and 
Exchange Commission and any stock exchange or similar authority;

(3) seek or obtain, as the undersigneds representative and
the undersigneds behalf, information regarding transactions in 
the Companys securities from any third party, including 
brokers, employee benefit plan administrators and trustees, and 
the undersigned herby authorizes any such person to release any 
such information to such attorney-in-fact and approves and 
ratifies any such release of information; and 

(4) take any other action of any type whatsoever in connection 
with the foregoing which, in the opinion of such attorney-in-
fact, may be of benefit to, in the interest of, or legally 
required by, the undersigned, it being understood that the 
documents executed by such attorney-in-fact on behalf of the 
undersigned pursuant to this Power of Attorney shall be in such 
form and shall contain such terms and conditions as such 
attorney-in-fact may approve in such attorney-in-facts 

The undersigned herby grants to each such attorney-in-fact full 
power and authority to do and perform any and every act and 
thing whatsoever requisite, necessary, or proper to be done in 
the exercise of any of the rights and powers herein granted, as 
fully to all intents and purposes as to the undersigned might or 
could do of personally present, with full power of substitution 
or revocation, hereby ratifying and confirming all that such 
attorney-in-fact or such attorney-in-facts substitute or 
substitutes, shall lawfully do or cause to be done by virtue of 
this power of attorney and the rights and powers herein granted. 
The undersigned acknowledges that the foregoing attorneys-in-
fact, in serving in such capacity at the request of the 
undersigned, are not assuming nor relieving, nor is the Company 
assuming nor relieving, any of the undersigneds 
responsibilities to comply with Section 16 of the Exchange Act. 
The undersigned Acknowledges that neither the company nor the 
foregoing attorneys-in-fact assume (i) any liability of the 
undersigneds responsibility to comply with the requirements of 
the Exchange Act, (ii) any liability of the undersigned for any 
failure to comply with such requirements, or (iii) any 
obligation or liability of the undersigned for profit 
disgorgement under Section 16(b) of the Exchange Act.

This Power of Attorney shall remain in full force and effect 
until the undersigned is no longer required to file Forms 3, 4, 
and 5 with respect to the undersigneds holdings of and 
transactions in securities issued by the Company, unless earlier 
revoked by the undersigned in a signed writing delivered to the 
foregoing attorneys-in-fact.

IN WITNESS WHEROF, the undersigned has caused this Power of 
Attorney to be executed as of this 13th day of August, 2019.

Jeffrey V. Poulton
Print Name

/s/ Jeffrey V. Poulton