X0306 4 2013-06-12 0000912183 CUBIST PHARMACEUTICALS INC CBST 0001542650 Lawton Alison Frances 65 HAYDEN AVENUE LEXINGTON MA 02421 1 Common Stock 2013-06-12 4 A 0 995 0 A 2714 D Stock Options (Right to Buy) 50.24 2013-06-12 4 A 0 8370 0 A 2014-06-12 2023-06-12 Common Stock 8370 8370 D Restricted Stock Units 2013-06-12 4 A 0 1104 0 A 2014-06-12 Common Stock 1104 1104 D The Reporting Person elected to receive the entire amount of his/her annual retainer for service as a Director in common stock. The shares of common stock reported in the table represents the shares of common stock issued to the Reporting Person for the annual retainer that was payable to the Reporting Person as of the Issuer's June 12, 2013 Annual Meeting of Stockholders. The number of stock options represents the fair value of $129,500 calculated using the Black-Scholes option pricing model in accordance with ASC Topic 718, rounded down to the nearest whole share. Options vest 100% on the earlier of the first anniversary of the grant date or the date of the Company's 2014 Annual Meeting of Stockholders. Each restricted stock unit represents a contingent right to receive one share of Cubist common stock for no consideration. The number of restricted stock units is equal to the fair value of $55,500 based on the stock price on the grant date, rounded down to the nearest whole share. The restricted stock units vest 100% on the earlier of the first anniversary of the grant date or the date of the Company's 2014 Annual Meeting of Stockholders. /s/ Joseph L. Farmer - Attorney in fact 2013-06-14