Item 8.01. Other Events.

Alnylam Pharmaceuticals, Inc. is filing the risk factors attached hereto as Exhibit 99.1 for the purpose of updating and superseding the risk factor disclosure contained in its prior public filings, including those discussed under the caption "Risk Factors" in its Annual Report on Form 10-K for the year ended December 31, 2011, which was filed with the Securities and Exchange Commission ("SEC") on February 13, 2012, and its Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2012, which was filed with the SEC on November 5, 2012.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

99.1 Risk Factors

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