Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) today announced positive top-line results from the second of two pivotal Phase 3 trials evaluating the safety and efficacy of fidaxomicin (OPT-80) in patients with Clostridium difficile Infection (CDI). This study was conducted in approximately 100 clinical sites throughout North America and Europe. The Company plans to use data from this study to support submission of a New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) in the second half of 2010.
The trial met the primary endpoint of non-inferiority with 91.7% of patients treated with fidaxomicin (per protocol population) achieving clinical cure vs. 90.6% for Vancocin, the only FDA-approved therapy for CDI. Importantly, fidaxomicin also had significantly lower recurrence rates and higher global cure rates (defined as cure with no recurrence within four weeks of completing therapy) compared to Vancocin. Only 12.8% of patients treated with fidaxomicin experienced a recurrence vs. 25.3% of patients treated with Vancocin (p = 0.002). Additionally, 79.6% of patients treated with fidaxomicin achieved a global cure versus 65.5% of patients treated with Vancocin (p < 0.001). As in the first Phase 3 trial, fidaxomicin was well-tolerated in the study.