INSM Insmed Inc

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): August 18, 2014

INSMED INCORPORATED

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (908) 997-9900

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 August 18, 2014, Insmed Incorporated (the “Company”) issued 10,235,000 shares (the “Shares”) of its common stock par value $0.01 per share pursuant to an underwriting agreement, dated August 12, 2014 (the “Underwriting Agreement”) with Leerink Partners LLC, as representative of the several underwriters. The number of Shares sold by the Company reflects the underwriters’ exercise in full of their option to purchase additional shares. The offering of the Shares was registered under the Securities Act of 1933, as amended, pursuant to the Company’s shelf registration statement on Form S-3, which became automatically effective upon filing.

The opinion of DLA Piper LLP (US) relating to the validity of the shares offered and sold pursuant to the Underwriting Agreement, is filed as Exhibit 5.1 to this report and incorporated herein by reference.

On August 18, 2014, the Company issued a press release announcing the closing of the offering of the Shares and the underwriters’ exercise in full of their option to purchase additional shares.  A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits.

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SIGNATURES

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.

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Exhibit 5.1

August 18, 2014

Insmed Incorporated

10 Finderne Avenue, Building 10

Bridgewater, New Jersey 08807

RE: Insmed Incorporated Registration Statement on Form S-3

Ladies and Gentlemen:

We have acted as counsel to Insmed Incorporated, a Virginia corporation (the “Company”), in connection with the offering by the Company of 10,235,000 shares of Common Stock, par value $0.01 per share (the “Common Stock”), of the Company (the “Shares”), pursuant to the referenced Registration Statement (the “Registration Statement”) and the Prospectus Supplement dated August 12, 2014 (the “Prospectus Supplement”), each filed under the Securities Act of 1933, as amended (the “Act”), with the Securities and Exchange Commission (the “SEC”).

In connection with this opinion letter, we have examined the Registration Statement, the Prospectus Supplement and originals, or copies certified or otherwise identified to our satisfaction, of the Articles of Incorporation, as amended, of the Company as filed with the State Corporation Commission of the Commonwealth of Virginia, the Amended and Restated Bylaws of the Company and the minutes of meetings of the shareholders and the Board of Directors of the Company, and the Pricing Committee thereof, as provided to us by the Company and such other documents, records and other instruments as we have deemed appropriate for purposes of the opinion set forth herein.

We have assumed the genuineness of all signatures, the legal capacity of all natural persons, the authenticity of the documents submitted to us as originals, the conformity with the originals of all documents submitted to us as certified, facsimile or photostatic copies and the authenticity of the originals of all documents submitted to us as copies.

Based upon the foregoing, we are of the opinion that the Shares have been duly authorized by the Company and are validly issued, fully paid and nonassessable.

The opinion expressed herein is limited to the Virginia Stock Corporation Act.

We hereby consent to the use of this opinion as Exhibit 5.1 to the Registration Statement and to the reference to us under the caption “Legal Matters” in the prospectus included in the Registration Statement and the Prospectus Supplement. In giving such consent, we do not hereby admit that we are acting within the category of persons whose consent is required under Section 7 of the Act or the rules or regulations of the SEC thereunder.

Very truly yours,

/s/ DLA Piper LLP (US)

Exhibit 99.1

Insmed Announces Closing of Public Offering and Exercise of Option to Purchase Additional Shares

BRIDGEWATER, N.J. (August 18, 2014) — Insmed Incorporated (Nasdaq: INSM) announced the closing of a $115.1 million underwritten public offering of 10,235,000 shares of common stock, including 1,335,000 shares of common stock which were issued pursuant to the exercise of the underwriters’ option to purchase additional shares, at a price of $11.25 per share to the public.  The net proceeds to Insmed from this offering were approximately $108 million, after deducting underwriting discounts and commissions and other estimated offering expenses payable by Insmed.

Insmed intends to use the net proceeds from this offering to fund further clinical development of ARIKAYCE™, or liposomal amikacin for inhalation, to treat nontuberculous mycobacteria (NTM) lung disease patients and Pseudomonas aeruginosa lung infections in cystic fibrosis (CF) patients, to fund its efforts to obtain regulatory approvals and commercialize ARIKAYCE for NTM patients and Pseudomonas aeruginosa in CF patients, to invest in increased third-party manufacturing capacity in anticipation of possible commercial launch of ARIKAYCE in Europe and the United States, and the balance to fund working capital, capital expenditures, general research and development, and other general corporate purposes, which may include the acquisition or in-license of additional compounds, product candidates, technology or businesses.

Leerink Partners LLC acted as sole book-running manager, Piper Jaffray & Co. and JMP Securities LLC acted as lead managers, and H.C. Wainwright & Co., LLC acted as co-manager for the offering.

A shelf registration statement on Form S-3 relating to the public offering of the shares of common stock described above was filed with the Securities and Exchange Commission (the “SEC”) and was automatically effective upon filing. A final prospectus supplement relating to the offering has been filed with the SEC and is available on the SEC’s website at www.sec.gov.  Copies of the final prospectus supplement and accompanying prospectus may also be obtained from Leerink Partners LLC, Attention: Syndicate Department, One Federal Street, 37th Floor, Boston, MA 02110, by telephone at 1-800-808-7525 or by email at Syndicate@Leerink.com.

This press release shall not constitute an offer to sell or a solicitation of an offer to buy, nor shall there be any sale of these securities in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Insmed

Insmed Incorporated is a biopharmaceutical company dedicated to improving the lives of patients battling serious lung diseases. Insmed is focused on the development and commercialization of ARIKAYCE, or liposomal amikacin for inhalation, for at least two identified

orphan patient populations: patients with nontuberculous mycobacteria (NTM) lung infections and cystic fibrosis (CF) patients with Pseudomonas aeruginosa lung infections.

Forward-Looking Statements

This release contains forward-looking statements. Words, and variations of words, such as “intend,” “expect,” “will,” “anticipate,” “believe,” “continue,” “propose” and similar expressions are intended to identify forward-looking statements. Investors are cautioned that such statements in this release, including statements relating to the expected offering, the intended use of proceeds, the status, results and timing of clinical trials and clinical data, the anticipated benefits of Insmed’s products, the anticipated timing of regulatory submissions, and the ability to obtain required regulatory approvals, bring products to market and successfully commercialize products constitute forward-looking statements that involve risks and uncertainties that could cause actual results to differ materially from those in the forward-looking statements. Such risks and uncertainties include, without limitation, market conditions, failure or delay of European, Canadian, U.S. Food and Drug Administration and other regulatory reviews and approvals, competitive developments affecting the Company’s product candidates, delays in product development or clinical trials or other studies, patent disputes and other intellectual property developments relating to the Company’s product candidates, unexpected regulatory actions, delays or requests, the failure of clinical trials or other studies or results of clinical trials or other studies that do not meet expectations, the fact that subsequent analyses of clinical trial or study data may lead to different (including less favorable) interpretations of trial or study results or may identify important implications of a trial or study that are not reflected in Company’s prior disclosures, and the fact that trial or study results or subsequent analyses may be subject to differing interpretations by regulatory agencies, the inability to successfully develop the Company’s product candidates or receive necessary regulatory approvals, the inability to make product candidates commercially successful, changes in anticipated expenses, changes in the Company’s financing requirements or ability to raise additional capital, and other risks and challenges detailed in the Company’s filings with the U.S. Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2013 and its subsequent quarterly reports on Form 10-Q. Investors are cautioned not to place undue reliance on any forward-looking statements that speak only as of the date of this news release. The Company undertakes no obligation to update these forward-looking statements to reflect events or circumstances or changes in its expectations.

Insmed Incorporated

Andrew T. Drechsler, 908-947-4327

Chief Financial Officer

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