X0206 3 2013-05-08 0 0001142576 OPTIMER PHARMACEUTICALS INC OPTR 0001576510 Sirota Eric 101 HUDSON STREET SUITE 3501 JERSEY CITY NJ 07302 0 1 0 0 Chief Operating Officer Common Stock 2129 D Includes 2,129 shares underlying a restricted stock unit that will vest upon the reporting person's separation from the Company. /s/ Meredith Schaum, attorney-in-fact 2013-05-13