Exhibit 99.1

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

MONMOUTH JUNCTION, N.J. (July 22, 2013) Insmed, Inc., (NASDAQ: INSM) today announced the closing of a $71.8 million underwritten public offering of 6,900,000 shares of common stock, including 900,000 shares of common stock which were issued pursuant to the exercise of the underwriters’ option to purchase additional shares, at a price of $10.40 per share to the public.  The net proceeds to Insmed from this offering were approximately $67.0 million, after deducting underwriting discounts and commissions and other estimated offering expenses payable by Insmed.

Leerink Swann LLC acted as sole book-running manager for the offering.  Lazard Capital Markets LLC and Canaccord Genuity Inc. acted as co-managers of 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 declared effective on June 5, 2013.  A final prospectus supplement related 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 Swann 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 the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or other 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 ARIKACE®, or liposomal amikacin for inhalation, for at least two identified orphan patient populations: cystic fibrosis (CF) patients with Pseudomonas aeruginosa lung infections and patients with non-tuberculous mycobacteria (NTM) 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 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, 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, inability to make product candidates commercially successful, changes in anticipated expenses, changes in the Company’s financing requirements or ability 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, 2012.  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.

Contact:

Andrew T. Drechsler

Chief Financial Officer

Insmed Incorporated

(732) 997-4600

Andy.Drechsler@Insmed.com

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