Optimer Pharmaceuticals Phase 3 Clinical Trials show Fidaxomicin is Superior to Vancomycin in Treatment of Recurrent Clostridium difficile Infection (CDI); Data Presented at ICAAC

SAN DIEGO, Sept. 14 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) announced the presentation of new data from its North American and European fidaxomicin Phase 3 clinical trials in patients with Clostridium difficile infection (CDI) at the 50th Annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Boston.  During an oral presentation, investigator Oliver Cornely, M.D., of the University of Cologne, presented data showing that fidaxomicin was superior to vancomycin in treating a CDI recurrence and in reducing the chance of another relapse.

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CDI recurrence occurs in approximately 25% of patients treated with existing therapies and there is no agreement in the medical community on the optimal treatment for a recurrence.  In the two fidaxomicin Phase 3 trials, a separate stratum was constructed of subjects who had experienced a prior CDI episode and recurred within three months of entering the study.  The 178 subjects with recurrent CDI  were randomized to be treated with either fidaxomicin or vancomycin and 128 of these subjects were subsequently evaluable for recurrence within the study. Following treatment, 35.5% (22/62) of the subjects who received vancomycin experienced another recurrence compared to 19.7% (13/66) among the subjects who received fidaxomicin (p=.045).  This equates to a 45% reduction in repeat CDI recurrence with fidaxomicin.

"The Phase 3 trials previously showed that fidaxomicin is superior to vancomycin in the prevention of recurrence.  The data presented today show that fidaxomicin is also superior to vancomycin in the treatment of CDI patients suffering a recurrence," said Sherwood Gorbach, Optimer's Chief Medical Officer and Senior Vice President of Medical Affairs.  "This is an important finding given that the medical community has not found a successful and reliable treatment for recurrent CDI.  With our recent MAA filing and anticipated NDA filing, we continue to work diligently to make fidaxomicin available to the medical community for treating acute CDI and for preventing and treating recurrences."

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Fidaxomicin Clinical Studies

The two fidaxomicin Phase 3 clinical studies were multi-center, randomized, double-blind trials, which enrolled a total of 1,164 adult subjects.  Subjects with confirmed CDI received either fidaxomicin (200 mg q12h) or Vancocin® (125 mg q6h), the only FDA approved product for the treatment of CDI. These studies were designed to evaluate safety and compare the response to treatment in subjects during and after a 10-day course of therapy. The primary endpoint was non-inferiority compared to Vancocin in clinical cure (defined as patients requiring no further CDI therapy two days after completion of study medication, as determined by the investigator).  If cured, subjects were monitored for a subsequent four-week period to evaluate recurrence, which was a secondary endpoint.  Global cure, also a secondary endpoint, was defined as patients who were cured and did not have a recurrence during this subsequent four-week period. In both of these studies, fidaxomicin achieved its primary endpoint of non-inferiority compared to Vancocin.  Fidaxomicin was also statistically superior to Vancocin in global cure rate and in reducing recurrences of CDI.

About Clostridium difficile Infection

CDI has become a significant medical problem in hospitals, long-term care facilities, and in the community.  It is a serious illness caused by infection of the inner lining of the colon by C. difficile bacteria, which produces toxins that cause inflammation of the colon, severe diarrhea and, in the most serious cases, death.  Patients typically develop CDI from the use of broad-spectrum antibiotics that disrupt normal gastrointestinal (gut) flora, and thus allowing C. difficile bacteria to flourish.

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

Primary risk factors for CDI include broad-spectrum antibiotic use (such as cephalosporins and fluoroquinolones), advanced age (over 65) and exposure to emerging hyper-virulent strains (BI/NAP1/027, 078, 001) of C. difficile. Increasing incidence, higher treatment failures and recurrence with current therapies have resulted in greater awareness and concern of CDI among medical professionals and public health officials.

About Fidaxomicin

Fidaxomicin is the first in a new class of antibiotics called macrocycles, which inhibit the bacterial enzyme RNA polymerase, resulting in the death of C. difficile. The narrow-spectrum profile of fidaxomicin may eradicate C. difficile selectively with minimal disruption to the normal intestinal flora, while the alternative antibiotics to treat CDI, metronidazole and vancomycin, disrupt the flora. Fidaxomicin may facilitate the return of normal physiological conditions in the colon which may be responsible for reducing CDI recurrence.

About Optimer Pharmaceuticals

Optimer Pharmaceuticals, Inc. is a biopharmaceutical company focused on discovering, developing and commercializing hospital specialty products to treat serious infections and address unmet medical needs. Optimer has two anti-infective product candidates in development. Fidaxomicin is a narrow spectrum antibiotic being developed for the treatment of Clostridium difficile infection (CDI). Optimer has completed two Phase 3 trials of fidaxomicin for the treatment of CDI demonstrating that fidaxomicin was statistically superior to vancomycin in global cure rate (defined as cure with no recurrence within four weeks of completing therapy) as well as statistically superior in reducing recurrences of CDI by up to 50% when compared with vancomycin, the only FDA approved product for CDI. Optimer has also successfully completed two Phase 3 trials of Pruvel™ a prodrug in the fluoroquinolone class of antibiotics being developed as a treatment for infectious diarrhea. Additional information can be found at http://www.optimerpharma.com.

Forward-looking Statements

Statements included in this press release that are not a description of historical facts are forward-looking statements, including without limitation all statements related to the ability of fidaxomicin to treat CDI and address current treatment limitations, expectations regarding regulatory filings and the potential to bring fidaxomicin to the market. Words such as "believes," "anticipates," "plans," "expects," "intend," "will," "goal" and similar expressions are intended to identify forward-looking statements. The inclusion of forward-looking statements should not be regarded as a representation by Optimer that any of its plans will be achieved. Actual results may differ materially from those set forth in this release due to the risks and uncertainties inherent in Optimer's business including, without limitation, risks relating to: the timing, progress and likelihood of success of its product research and development programs, the timing and status of its preclinical and clinical development of potential drugs, Optimer's ability to complete its NDA submission in a timely manner, whether regulatory authorities will review or approve Optimer's applications for marketing approval, the timing of any marketing approvals, Optimer's ability to commercialize any products for which it receives marketing approval and other risks detailed in Optimer's filings with the Securities and Exchange Commission.

SOURCE Optimer Pharmaceuticals, Inc.