UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): April 6, 2011

Alnylam Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware	000-50743	77-0602661
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)

300 Third Street, Cambridge, MA	02142
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s telephone number, including area code: (617) 551-8200

Not applicable
(Former Name or Former Address, if Changed Since Last Report)

     Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01. Other Events.

On April 6, 2011, Alnylam Pharmaceuticals, Inc. (the “Company”) served and filed an Answer and Counterclaim in the action entitled Tekmira Pharmaceuticals Corporation and Protiva Biotherapeutics, Inc., v. Alnylam Pharmaceuticals, Inc. pending in the Business Litigation Section of the Suffolk County Superior Court, in Boston, Massachusetts. A copy of the Company’s Answer and Counterclaim is attached to this Current Report on Form 8-K as Exhibit 99.1 and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

99.1 Answer and Counterclaim of Alnylam Pharmaceuticals, Inc.

SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	ALNYLAM PHARMACEUTICALS, INC.
Date: April 6, 2011	By:	/s/ Michael P. Mason
		Michael P. Mason
		Vice President, Finance and Treasurer

EXHIBIT INDEX

Exhibit No.		Description
	99.1	Answer and Counterclaim of Alnylam Pharmaceuticals, Inc.