Exhibit 5.1

 

				Goodwin Procter LLP 100 Northern Avenue Boston, MA 02210   goodwinlaw.com +1 617 570 1000

June 5, 2020

Alnylam Pharmaceuticals, Inc.

675 West Kendall Street

Henri A. Termeer Square

Cambridge, Massachusetts 02142

 

Re:

Securities Registered under Registration Statement on Form S-3

We have acted as counsel to you in connection with your filing of a Registration Statement on Form S-3 (as amended or supplemented, the “Registration Statement”) filed on June 5, 2020 with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), relating to the registration of the sale of up to 963,486 shares (the “Selling Stockholder Shares”) of common stock, par value $0.01 per share (“Common Stock”) of Alnylam Pharmaceuticals, Inc., a Delaware corporation (the “Company”) to be sold by the selling stockholders listed in the Registration Statement under “Selling Stockholders” (the “Selling Stockholders”). The Shares may be sold by the Selling Stockholders named in, and pursuant to, a stock purchase agreement among the Company and such Selling Stockholders, dated as of April 10, 2020 (the “Stock Purchase Agreement”).

We have reviewed such documents and made such examination of law as we have deemed appropriate to give the opinions set forth below. We have relied, without independent verification, on certificates of public officials and, as to matters of fact material to the opinions set forth below, on certificates of officers of the Company. For purposes of the opinion set forth below, we have assumed that before the Shares are issued the Company does not issue shares of Common Stock or reduce the total number of shares of Common Stock that the Company is authorized to issue under its certificate of incorporation such that the number of unissued shares of Common Stock authorized under the Company’s certificate of incorporation is less than the number of Shares.

The opinion set forth below is limited to the Delaware General Corporation Law.

Based on the foregoing, we are of the opinion that the Selling Stockholder Shares have been duly authorized and validly issued and are fully paid and nonassessable.

Alnylam Pharmaceuticals, Inc.

June 5, 2020

Page 2

 

We hereby consent to the inclusion of this opinion as Exhibit 5.1 to the Registration Statement and to the references to our firm under the caption “Legal Matters” in the Registration Statement. In giving our consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations thereunder.