X0204 3 2012-01-31 0 0001274792 MERRIMACK PHARMACEUTICALS INC MACK 0001094201 CROCKER GARY L C/O MERRIMACK PHARMACEUTICALS, INC. ONE KENDALL SQUARE, SUITE B7201 CAMBRIDGE MA 02139 1 0 0 0 Series C Convertible Preferred Stock Common Stock 59863 D Series D Convertible Preferred Stock Common Stock 463654 D Series E Convertible Preferred Stock Common Stock 46676 D Series F Convertible Preferred Stock Common Stock 41900 D Series G Convertible Preferred Stock Common Stock 313266 D Series C Convertible Preferred Stock Common Stock 15863 I By Crocker Enterprises, LLC Series D Convertible Preferred Stock Common Stock 30000 I By Crocker Enterprises, LLC Series E Convertible Preferred Stock Common Stock 300000 I By Crocker Ventures, LLC Series C Convertible Preferred Stock Common Stock 184975 I By Wife Series D Convertible Preferred Stock Common Stock 35714 I By Wife Series C Convertible Preferred Stock Common Stock 79000 I By Daughter Series D Convertible Preferred Stock Common Stock 21429 I By Daughter Series E Convertible Preferred Stock Common Stock 28332 I By Daughter Series F Convertible Preferred Stock Common Stock 23300 I By Daughter Series G Convertible Preferred Stock Common Stock 22000 I By Daughter Series C Convertible Preferred Stock Common Stock 79000 I By Son Series D Convertible Preferred Stock Common Stock 21429 I By Son Series E Convertible Preferred Stock Common Stock 28332 I By Son Series F Convertible Preferred Stock Common Stock 23300 I By Son Series G Convertible Preferred Stock Common Stock 22000 I By Son Series F Convertible Preferred Stock Common Stock 450000 I By Trust Stock Option (right to buy) 1.2500 2014-04-22 Common Stock 50000 D Stock Option (right to buy) 1.2500 2014-08-30 Common Stock 35000 D Stock Option (right to buy) 1.7100 2015-08-03 Common Stock 35000 D Stock Option (right to buy) 2.4700 2016-08-01 Common Stock 50000 D Stock Option (right to buy) 2.5900 2017-10-04 Common Stock 35000 D Stock Option (right to buy) 1.8100 2018-09-21 Common Stock 35000 D Stock Option (right to buy) 2.1200 2019-11-04 Common Stock 50000 D Stock Option (right to buy) 5.5400 2021-05-02 Common Stock 66250 D Each share of Series C Convertible Preferred Stock will automatically convert into one share of Common Stock upon the closing of the issuer's initial public offering. The shares have no expiration date. Each share of Series D Convertible Preferred Stock will automatically convert into one share of Common Stock upon the closing of the issuer's initial public offering. The shares have no expiration date. Each share of Series E Convertible Preferred Stock will automatically convert into one share of Common Stock upon the closing of the issuer's initial public offering. The shares have no expiration date. Each share of Series F Convertible Preferred Stock will automatically convert into one share of Common Stock upon the closing of the issuer's initial public offering. The shares have no expiration date. Each share of Series G Convertible Preferred Stock will automatically convert into one share of Common Stock upon the closing of the issuer's initial public offering. The shares have no expiration date. This option is fully vested. /s/ Jeffrey A. Munsie, attorney-in-fact 2012-02-01