424B3

Prospectus Supplement No. 1

to Prospectus dated August 23, 2005

as filed on August 5, 2005

 

Filed pursuant to Rule 424(b)(3)

Registration No. 333-123695

 

INSMED INCORPORATED

 

51,770,481 SHARES

COMMON STOCK

 

This prospectus supplement supplements the information contained in the prospectus of Insmed Incorporated dated August 23, 2003 filed as part of Post-Effective Amendment No. 1 to Form S-3 Registration Statement (333-123695) filed by Insmed on August 5, 2005 relating to the potential resale from time to time of the 51,770,481 shares of Insmed Common Stock issuable upon conversion of the 5% Convertible Notes due 2008-2010 issued by Insmed and warrants to purchase Common Stock issued by Insmed. This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the prospectus, including any amendments or supplements thereto.

 

The following table supplements the information set forth in the prospectus under the caption “Selling Stockholders” with respect to the selling stockholders and the respective principal amount of notes which are beneficially owned and may be sold by each selling stockholder, and the number of shares of common stock that may be sold by the selling stockholders pursuant to this prospectus, as amended or supplemented:

 

Investor


   Number of Shares Owned
Before Offering


   Number of Shares
Offered Pursuant
to the Prospectus


   Number of Shares
Owned After Offering


Investor    Number

   Percent

   Number

   Number

   Percent

Xmark Opportunity Fund, Ltd.(1)

   233,643    *    233,643       *

Xmark Opportunity Fund, L.P.(2)

   150,142    *    150,142       *

* Less than 1%

 

(1) Includes 233,643 shares of common stock issuable upon conversion and exercise of convertible notes and warrants.

 

(2) Includes 150,142 shares of common stock issuable upon conversion and exercise of convertible notes and warrants.

 

THE DATE OF THIS PROSPECTUS SUPPLEMENT IS DECEMBER 15, 2005