Optimer Pharmaceuticals, Inc. Completes Enrollment in Second Fidaxomicin Phase 3 Clinical Trial in Patients With Clostridium difficile Infection

SAN DIEGO, Nov. 12 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc. today announced that it has completed enrollment in the second of two pivotal Phase 3 clinical trials evaluating the safety and efficacy of fidaxomicin (OPT-80) for the treatment of Clostridium difficile infection, or CDI.

"Completing enrollment in the second Phase 3 trial is a major milestone in the development of fidaxomicin. The two fidaxomicin trials combined represent the largest CDI database in the world, and will be an important tool for the medical community in understanding the epidemiology of this infection," said Michael N. Chang, Ph.D., President and CEO of Optimer. "We will complete the analysis of the data from this trial and we expect to report top-line results in the first quarter of 2010."

Fidaxomicin Clinical Study Design

About Clostridium Difficile Infection

Current therapeutic options for CDI include the off-label use of metronidazole or oral vancomycin, the only FDA approved treatment for CDI. However, approximately 20% to 30% of CDI patients who initially respond to these treatments experience a clinical recurrence following cessation of antibiotic administration.

About Fidaxomicin

About Optimer Pharmaceuticals

Forward-looking Statements

CONTACT: John Prunty, CFO & VP, Finance, or Christina Donaghy, Corporate
Communications Manager, both of Optimer Pharmaceuticals, Inc.,
+1-858-909-0736; or Jason I. Spark, Vice President of Porter Novelli Life
Sciences, +1-619-849-6005

Web site: http://www.optimerpharma.com/