CONVERSION AGREEMENTConversion Agreement • April 14th, 2016 • Merrimack Pharmaceuticals Inc • Pharmaceutical preparations
(the “Undersigned”), for itself and on behalf of the beneficial owners listed on Exhibit A hereto (“Accounts”) for whom the Undersigned holds contractual and investment authority (each Account, as well as the Undersigned if it is exchanging Notes (as defined below) hereunder, a “Holder”), enters into this Conversion Agreement (this “Agreement”) with Merrimack Pharmaceuticals, Inc. (the “Company”) on April , 2016 whereby, in exchange for the Initial Shares (as defined below) and the Additional Shares (as defined below), the Holders will convert the Company’s 4.50% Convertible Senior Notes due 2020 (the “Notes”) into shares of common stock of the Company, par value $0.01 per share (the “Common Stock”) pursuant to the provisions of the Base Indenture, dated as of July 17, 2013 (the “Base Indenture”), as supplemented by the First Supplemental Indenture, dated as of July 17, 2013 (the “First Supplemental Indenture” and, together with the Base Indenture, the “Indenture”), in each case betwee
