Sec Form 4 Filing - ROBERTS BRYAN E @ IRONWOOD PHARMACEUTICALS INC - 2015-06-15

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person ROBERTS BRYAN E 2. Issuer Name and Ticker or Trading Symbol IRONWOOD PHARMACEUTICALS INC [ IRWD] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O VENROCK, 3340 HILLVIEW AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 06/15/2015 (Street) PALO ALTO, CA94304 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Stock 06/15/2015 A( 1 ) 145 A $ 12.06 ( 2 ) 31,951 D ( 3 ) Class A Common Stock 33,117 I By LLC ( 4 ) Class A Common Stock 18,910 I By Funds ( 5 ) Class B Common Stock 40,000 I By LLC ( 6 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or I ndirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other ROBERTS BRYAN E C/O VENROCK 3340 HILLVIEW AVENUE PALO ALTO, CA94304 X Signatures /s/ Bryan E. Roberts 06/16/2015 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Issued pursuant to Director Compensation Plan, effective as of January 2014. ( 2 )The shares of the Issuer's Class A Common Stock were issued to the reporting person for service as the Issuer's Chair of the Board of Directors for the second quarter of fiscal 2015 in the aggregate amount of $1,749. ( 3 )The reporting person is a member of VR Management, LLC (the "Management Company"). Under an agreement between the reporting person and the Management Company, the reporting person is deemed to hold 16,866 of the reported shares for the sole benefit of the Management Company (the "Management Company Shares") and must hold or sell these Management Company Shares solely upon the direction of the Management Company. The Management Company may be deemed the indirect beneficial owner of these Management Company Shares, and the reporting person may be deemed the indirect beneficial owner of these Management Company Shares through his interest in the Management Company. The reporting person disclaims beneficial ownership of these Management Company Shares except to the extent of his indirect pecuniary interest therein. ( 4 )Consists of 33,117 shares of Class A Common Stock of the Issuer held by the Management Company. Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein. ( 5 )VHCP Management, LLC ("VHCP Management") holds an aggregate of 18,910 shares of Class A Common Stock of the Issuer. Dr. Roberts is a managing member of VHCP Management and may be deemed to beneficially own these shares. Dr. Roberts expressly disclaims beneficial ownership over these shares except to the extent of his indirect pecuniary interest therein. ( 6 )Consists of 40,000 shares of Class B Common Stock of the Issuer held by the Managment Company. Dr. Roberts is a member of the Management Company and may be deemed to beneficially own these shares. Dr. Roberts disclaims beneficial ownership of these shares except to the extent of his indirect pecuniary interest therein.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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