Optimer Pharmaceuticals, Inc. Announces Combined Data From Fidaxomicin Phase 3 Trials for the Treatment of Clostridium difficile Infection (CDI) Presented at IDSA

SAN DIEGO, Oct. 23 /PRNewswire/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) announced today the presentation of combined data from its two fidaxomicin Phase 3 trials in patients with Clostridium difficile infection (CDI) at the 48th Annual Meeting of the Infectious Disease Society of America (IDSA) in Vancouver, British Columbia, Canada. During an oral presentation, investigator Derrick Crook, M.D., of the University of Oxford, presented combined data showing that CDI patients treated with fidaxomicin experienced 47% fewer recurrences than patients treated with vancomycin.

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Dr. Crook presented combined data from the two Phase 3 trials showing cure rates, recurrence rates and global cure rates for the intent to treat (ITT) population. The recurrence rates were 13% for the fidaxomicin arm compared to 24% for the vancomycin arm (p < 0.001). Global cure rates were 75% for fidaxomicin compared to 63% for vancomycin (p < 0.001). Cure rates were similar for both fidaxomicin and vancomycin (88% vs. 86%). Fidaxomicin was well-tolerated in both studies.

The combined results for the per protocol and modified intent to treat populations are shown in the table below:

“The combined data set of more than 1,100 patients show that fidaxomicin is statistically superior in preventing recurrences and achieving global cures compared to vancomycin. Fidaxomicin as a single agent offers potential advantages over existing therapies,” said Dr. Crook, Consultant Microbiology/Infectious Diseases and Professor of Infectious Diseases and Microbiology, Experimental Medicine Division, Nuffield Department of Clinical Medicine (NDM), University of Oxford.

For a complete list of abstracts, please visit the Resources page on our website: www.optimerpharma.com

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. 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 recurrence rate, reducing CDI recurrences by 47% and in global cure rate. Fidaxomicin was well tolerated in both studies.

About Fidaxomicin

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

About Clostridium difficile Infection (CDI)

Clostridium difficile infection (CDI), commonly referred to as c-diff., has become a significant medical problem in hospitals, long-term care facilities, and in the community and is estimated to afflict more than 700,000 people each year in the U.S. 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. Learn more about CDI at www.cdiinfo.org.

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 under development, fidaxomicin and Pruvel (prulifloxacin). Fidaxomicin is a narrow spectrum antibiotic being developed for the treatment of Clostridium difficile infection (CDI). We recently initiated a rolling submission of our NDA filing to the FDA, and filed a MAA to the EMA (Europe) for fidaxomicin. Pruvel is a prodrug in the fluoroquinolone class of antibiotics being developed as a treatment for infectious diarrhea. We plan to have an NDA submitted to the FDA in the first quarter of 2011. 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 and the potential for fidaxomicin to be a treatment of choice for CDI. 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, the development of alternative treatments for or means of preventing CDI, whether regulatory authorities will review or approve Optimer’s applications for marketing approval, the timing of any marketing approvals, Optimer’s ability to complete its NDA submission in a timely manner, Optimer’s ability to commercialize any products for which it receives marketing approval, whether healthcare professionals will prescribe fidaxomicin, if approved, whether fidaxomicin will receive reimbursement coverage from healthcare payors and government agencies and other risks detailed in Optimer’s filings with the Securities and Exchange Commission.

SOURCE Optimer Pharmaceuticals, Inc.