Item 1.01 - Entry into a Material Definitive Agreement.

On September 28, 2012, Insmed Incorporated, a Virginia corporation (the "Company"), entered into securities purchase agreements with certain investors for their purchase of an aggregate of 6,304,102 shares of the Company's common stock at a purchase price of $4.07 per share. The shares were offered and sold pursuant to a prospectus supplement, dated September 28, 2012, pursuant to the Company's effective shelf registration statement on Form S-3 (SEC File No. 333-182124). In connection with the offering, the Company expects to receive gross proceeds of approximately $25.7 million. The closing of the sale and issuance of the Company's securities in the offering is expected to take place on September 28, 2012, subject to the satisfaction of customary closing conditions.

The foregoing descriptions of the subscription agreements do not purport to be complete and are qualified in their entirety by the form of the subscription agreement attached as Exhibit 10.1 to this Current Report on Form 8-K, which is incorporated herein by reference.

The Company's press release, dated September 28, 2012, announcing the offering is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 8.01 - Other Events.

The Company filed a free writing prospectus with the Securities and Exchange Commission in connection with the offering, which is filed as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 9.01 - Financial Statements and Exhibits.

(d) Exhibits

Exhibit
No. Description

5.1 Opinion of Pepper Hamilton LLP

10.1 Form Subscription Agreement

23.1 Consent of Pepper Hamilton LLP (included in Exhibit 5.1)

99.1 Press Release, dated September 28, 2012

99.2 Free Writing Prospectus

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