EXHIBIT 1

JOINT FILING AGREEMENT

In accordance with Rule 13d−1(k)(1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing on behalf of each of them of a statement on Schedule 13D (including amendments thereto) with respect to the Common Stock of The Medicines Company and further agree that this Joint Filing Agreement be included as an Exhibit to such joint filings. In evidence thereof, the undersigned, being duly authorized, have executed this Joint Filing Agreement this 30^th day of May, 2019.

SARISSA CAPITAL MANAGEMENT LP
By:	/s/ Mark DiPaolo                                           Name: Mark DiPaolo Title: Senior Partner, General Counsel
SARISSA CAPITAL OFFSHORE MASTER FUND LP
By: Sarissa Capital Offshore Fund GP LLC, its general partner
By:	/s/ Mark DiPaolo                                           Name: Mark DiPaolo Title: Authorized Person
SARISSA CAPITAL CATAPULT FUND LLC
By: Sarissa Capital Management LP, its managing member
By:	/s/ Mark DiPaolo                                          Name: Mark DiPaolo Title: Senior Partner, General Counsel
SARISSA CAPITAL HAWKEYE FUND LP
By: Sarissa Capital Fund GP LP, its general partner
By:	/s/ Mark DiPaolo                                          Name: Mark DiPaolo Title: Authorized Person
SARISSA CAPITAL ATHENA FUND LTD
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.