UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No.1)*

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box.

Note:  Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits.  See Rule 13d-7 for other parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 or otherwise subject to the liabilities of that section of the Act but shall be  subject to all other  provisions of the Act  (however, see the Notes).

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This statement constitutes Amendment No. 1 to the Schedule 13D (this “Amendment No. 1”) relating to the Class A Common Stock, par value $0.001 (the “Shares”), issued by Ironwood Pharmaceuticals, Inc. (the “Issuer”), and hereby amends the Schedule 13D filed with the Securities and Exchange Commission on May 16, 2019 (the "Initial Schedule 13D"), on behalf of the Reporting Persons (as defined in the Initial Schedule 13D), to furnish the additional information set forth herein.  All capitalized terms contained herein but not otherwise defined shall have the meanings ascribed to such terms in the Initial Schedule 13D.

Item 3.  Source or Amount of Funds or Other Consideration.

Item 3 of the Initial Schedule 13D is hereby amended by adding the following:

The aggregate purchase price of the Shares being reported in Item 5(c) of this Amendment No. 1 was $24,838,288 (including commissions). The source of funding for these Shares was the general working capital of the respective purchasers.

Item 5.  Interest in Securities of the Issuer.

Items 5 (a) and (b) of the Initial Schedule 13D are hereby amended by replacing them in their entirety with the following:

(a) The Reporting Persons may be deemed to beneficially own, in the aggregate, 12,493,000 Shares representing approximately 7.90% of the Issuer’s outstanding Shares (based upon the 158,206,912 Shares stated to be outstanding as of February 10, 2020 by the Issuer in the Issuer’s Form 10-K filed with the Securities and Exchange Commission on February 13, 2020).

(b) For purposes of this Schedule 13D:

Sarissa Offshore has sole voting power and sole dispositive power with regard to 5,682,660 Shares.  Sarissa Catapult has sole voting power and sole dispositive power with regard to 1,948,655 Shares.  Sarissa Hawkeye has sole voting power and sole dispositive power with regard to 1,465,765 Shares.  Sarissa Athena has sole voting power and sole dispositive power with regard to 2,038,705 Shares.  Sarissa Capital, as the investment advisor to the Sarissa Funds, may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the 11,135,785 Shares held by the Sarissa Funds and the sole power to vote or direct the vote of (and the sole power to dispose or direct the disposition of) an additional 1,357,215 Shares held by the Sarissa Funds.  By virtue of his position as the Chief Investment Officer of Sarissa Capital and as the managing member of Sarissa Capital’s general partner and as controlling the ultimate general partner of each of Sarissa Offshore and Sarissa Hawkeye and the managing member of Sarissa Catapult, Dr. Denner may be deemed to have the shared power to vote or direct the vote of (and the shared power to dispose or direct the disposition of) the 12,493,000 Shares, in the aggregate, held by Sarissa Capital and the Sarissa Funds.

(c) The following table sets forth all transactions with respect to Shares effected during the past sixty (60) days by any of the Reporting Persons, inclusive of any transactions effected through 4:00 p.m., Eastern Standard Time, on February 26, 2020.  Except as otherwise noted below, all such transactions were purchases of Shares effected in the open market.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct.

Dated:  February 26, 2020

SARISSA CAPITAL MANAGEMENT LP

By:	/s/ Mark DiPaolo
	Name: Mark DiPaolo
	Title: Senior Partner, General Counsel

By:	/s/ Mark DiPaolo
	Name: Mark DiPaolo
	Title: Authorized Person

By:	/s/ Mark DiPaolo
	Name: Mark DiPaolo
	Title: Senior Partner, General Counsel

By:	/s/ Mark DiPaolo
	Name: Mark DiPaolo
	Title: Authorized Person

By:	/s/ Alexander J. Denner, Ph.D.
	Name: Alexander J. Denner, Ph.D.
	Title: Director

/s/Alexander J. Denner, Ph.D.
Alexander J. Denner, Ph.D.