Medicines (MDCO) Form 3 MEDICINES / ALEXANDER J DENNER ownership change

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

DENNER ALEXANDER J

(Last) (First) (Middle)

C/O SARISSA CAPITAL MANAGEMENT LP

660 STEAMBOAT ROAD

(Street)

GREENWICH CT 06830

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
02/02/2016

3. Issuer Name and Ticker or Trading Symbol
MEDICINES CO /DE [ MDCO ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	658,595	I	Sarissa Capital Offshore Master Fund LP(1)(2)
Common Stock	1,093,405	I	Sarissa Capital Domestic Fund LP(1)(3)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. The reporting person is the founding partner and Chief Investment Officer of Sarissa Capital Management L.P., investment advisor to this fund. As such and due to the positions set forth in footnotes (2) and (3), the reporting person may be deemed to beneficially own the securities owned by this fund. The reporting person disclaims any beneficial ownership of these securities, except to the extent of his pecuniary interest therein.

2. The reporting person is a partner of Sarissa Capital Fund GP LP, the sole member of the general partner of this fund.

3. The reporting person holds limited partnership interests in this fund and is a partner of Sarissa Capital Fund GP LP, the general partner of this fund.

Remarks:

	/s/ Alexander J. Denner, Ph.D.	02/04/2016
	** Signature of Reporting Person	Date
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 5 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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