Merrimack Pharmaceuticals, Inc. (NASDAQ:MACK) Files An 8-K Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers
Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On September13, 2017, the Board of Directors (the “Board”) of Merrimack Pharmaceuticals, Inc. (the “Company”), upon the recommendation of the Organization and Compensation Committee of the Board, approved the annual performance-based cash bonus program for 2017 (the “2017 Bonus Program”) for Richard Peters, the Company’s President and Chief Executive Officer, and Jean M. Franchi, the Company’s Chief Financial Officer and Treasurer.

The 2017 Bonus Program is comprised of the following two elements: (1)the achievement of specified annual individual performance objectives; and (2)the embodiment of the Company’s values and expected behaviors.

Dr.Peters’ individual performance objectives for 2017 generally relate to building the Company’s culture, staffing key positions, advancing the Company’s pipeline, enhancing the external reputation of the Company and pursuing various corporate development opportunities.

Ms.Franchi’s individual performance objectives for 2017 generally relate to managing the Company’s financials and related projections, enhancing the external reputation of the Company and meeting the Company’s financial disclosure requirements.

The Company’s values consist of being passionate, team focused, authentic and a continuous learner. The Company’s expected behaviors include thinking strategically, innovating and building the organization.

For each of the two foregoing elements, the Board will assess retroactively whether Dr.Peters and Ms.Franchi have not met expectations, have met expectations or have far exceeded expectations. The Board will then use the following table to determine the maximum percentage of Dr.Peters’ and Ms.Franchi’s target bonus for which he or she will be eligible. The Board may use its discretion to determine the amount of the bonus up to the maximum percentage provided.

For 2017, Dr.Peters’ target bonus is 65% of his 2017 base salary, provided that such bonus will be prorated based on his start date of February6, 2017, and Ms.Franchi’s target bonus is 35% of her 2017 base salary, provided that such bonus will be prorated based on her start date of August21, 2017.

Notwithstanding the foregoing, the Board has the authority to, in its sole discretion, increase the amount of the annual cash bonus above the maximum percentage provided in the table above.

About Merrimack Pharmaceuticals, Inc. (NASDAQ:MACK)

Merrimack Pharmaceuticals, Inc. is a biopharmaceutical company. The Company is engaged in discovering, developing and commercializing medicines consisting of therapeutics paired with companion diagnostics for the treatment of cancer. Its therapeutic oncology candidates in clinical development include MM-398, MM-302, MM-121, MM-141 and MM-151. Its ONIVYDE (irinotecan liposome injection), also known as MM-398, is an encapsulation of the marketed chemotherapy drug irinotecan in a liposomal formulation. MM-302 is an antibody drug conjugated liposomal doxorubicin that targets the ErbB2 (HER2) receptor. MM-121 is a fully human monoclonal antibody that targets Erb-B2 Receptor Tyrosine Kinase 3 (ErbB3). MM-141 is a fully human tetravalent bispecific antibody designed to block tumor survival signals by targeting receptor complexes. MM-151 is an oligoclonal therapeutic designed to bind to non-overlapping epitopes of EGFR (ErbB1).