X0306 4 2013-10-24 1 0001142576 OPTIMER PHARMACEUTICALS INC OPTR 0001209725 GREBOW PETER E C/O OPTIMER PHARMACEUTICALS, INC. 101 HUDSON STREET JERSEY CITY NJ 07302 1 0 0 0 Common stock 2013-10-24 4 D 0 7500 10.75 D 7500 D Common stock 2013-10-24 4 D 0 7500 10.75 D 0 D Stock option (right to buy) 10.85 2013-10-24 4 D 0 10000 1.93 D 2019-02-19 Common stock 10000 0 D Stock option (right to buy) 10.85 2013-10-24 4 D 0 5000 1.93 D 2019-02-19 Common stock 5000 0 D Stock option (right to buy) 11.85 2013-10-24 4 D 0 10000 0.93 D 2020-01-08 Common stock 10000 0 D Stock option (right to buy) 11.85 2013-10-24 4 D 0 10000 0.93 D 2020-01-08 Common stock 10000 0 D Stock option (right to buy) 9.56 2013-10-24 4 D 0 10000 3.22 D 2020-12-01 Common stock 10000 0 D Pursuant to the Agreement and Plan of Merger, dated as of July 30, 2013 (the "Merger Agreement"), among Optimer Pharmaceuticals, Inc. ("Optimer"), Cubist Pharmaceuticals, Inc. ("Cubist"), and PDRS Corporation, each award was converted into the right to receive per share consideration of: (i) $10.75 cash and (ii) one contingent value right issued by Cubist in accordance with the Contingent Value Rights Agreement, dated as of October 24, 2013, between Cubist and American Stock Transfer & Trust Company, LLC (together, the "Per Share Merger Consideration") with respect to each share of Optimer common stock subject to the award. Pursuant to the terms of the Merger Agreement, each award was fully vested and converted into the right to receive the Per Share Merger Consideration with respect to each share of Optimer common stock subject to the award. Pursuant to the terms of the Merger Agreement, each option was converted into the right to receive a cash payment equal to the excess, if any, of $12.78 (the last reported sale price of a share of Optimer common stock on The NASDAQ Global Select Market on October 23, 2013) over such option's per share exercise price. Peter E. Grebow 2013-10-28