Optimer Pharmaceuticals to present additional data on fidaxomicin at the 47th IDSA meeting

Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) announced that additional data related to fidaxomicin, the Company's lead developmental product candidate for the treatment of Clostridium difficile infection, will be presented at the 47th Annual Meeting of the Infectious Disease Society of America (IDSA) to be held at The Philadelphia Convention Center in Philadelphia, Pennsylvania October 29 through November 1, 2009.

"Age, Serum Albumin, and Leukocytosis/Fever Predict Clinical Outcomes of Clostridium difficile Infection Treated with Fidaxomicin and Vancomycin" Poster Presentation: Mark A. Miller, M.D. Friday, October 30, 2009 12:30pm-2:00pm Eastern Time Poster session: 053, Hospital-acquired and Transplant Infections Presentation #: 420 "Faster Time to Resolution of Diarrhea with Fidaxomicin vs. Vancomycin in Patients with Clostridium difficile Infection" Poster Presentation: Mark A. Miller, M.D. Friday, October 30, 2009 12:30pm-2:00pm Eastern Time Poster session: 053, Hospital-acquired and Transplant Infections Presentation #: 422 "Effect of Concomitant Antibiotics on Treatment of Clostridium difficile Infection with Fidaxomicin or Vancomycin" Poster Presentation: Kathleen M. Mullane, D.O. Saturday, October 31, 2009 12:30pm-2:00pm Eastern Time Poster session: 110, Late Breaker Posters Presentation #: LB-14