Merrimack Pharmaceuticals (MACK) 8-K Merrimack Announces Proposed Concurrent Public Offerings

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 10, 2013

Merrimack Pharmaceuticals, Inc.

(Exact Name of Registrant as Specified in its Charter)

Delaware	001-35409	04-3210530
(State or Other Jurisdiction of Incorporation	(Commission File Number)	(IRS Employer Identification No.)

One Kendall Square, Suite B7201 Cambridge, MA	02139
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s telephone number, including area code: (617) 441-1000

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01.  Other Events.

On July 10, 2013, Merrimack Pharmaceuticals, Inc. (the “Company”) issued a press release announcing its intention to offer, subject to market conditions and other factors, $50 million of its common stock and $75 million in aggregate principal amount of convertible senior notes due 2020 in concurrent underwritten public offerings pursuant to the Company’s effective Registration Statement on Form S-3 (File No. 333-186369).  The full text of the press release issued in connection with the announcement is attached to this Current Report on Form 8-K as Exhibit 99.1 and is incorporated herein by reference.

Item 9.01.  Financial Statements and Exhibits.

(d)  Exhibits.

See Exhibit Index attached hereto.

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MERRIMACK PHARMACEUTICALS, INC.
Date: July 10, 2013	By:	/s/ Jeffrey A. Munsie
		Jeffrey A. Munsie
		Vice President and General Counsel

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EXHIBIT INDEX

Exhibit No.	Description
99.1	Press release issued by Merrimack Pharmaceuticals, Inc. on July 10, 2013

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