Optimer Pharmaceuticals Announces FDA Acceptance of NDA for Filing and Designation of Priority Review for Fidaxomicin for the Treatment of Clostridium difficile Infection (CDI)

SAN DIEGO, Jan. 24, 2011 /PRNewswire/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) today announced that the U.S. Food and Drug Administration (FDA) has accepted for filing the Company's New Drug Application (NDA) for fidaxomicin for the treatment of Clostridium difficile infection (CDI) and for reducing the risk of recurrence when used for treatment of initial CDI. The FDA has also granted the Company's request for six-month Priority Review, and has assigned a Prescription Drug User Fee Act (PDUFA) goal date of May 30, 2011. Additionally, the FDA has informed us that it plans to discuss the NDA at a meeting of its Anti-Infective Drugs Advisory Committee currently scheduled for April 5, 2011.

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The acceptance of the fidaxomicin NDA for filing confirms the FDA's determination that the NDA is sufficiently complete to permit a substantive review.  A Priority Review classification is granted to drugs that, if approved, have the potential to provide significant improvements compared to marketed treatments, or provide a treatment where no satisfactory alternative therapy exists. A Priority Review means that the goal for the time it takes the FDA to review a new drug application is reduced. Based on this classification, the FDA has assigned a Prescription Drug User Fee Act (PDUFA) goal date of May 30, 2011 for its review of the NDA.

"In Phase 3 clinical trials, fidaxomicin not only showed a high clinical cure rate, but also demonstrated a statistically significant improvement in reducing recurrences, one of the major problems in the current management of CDI," said Pedro Lichtinger, Optimer's President and CEO.  "The agency's acceptance of our NDA represents a step forward to fulfill an unmet medical need and supports our goal of helping patients who are suffering from this disease." 

The NDA is supported by data from the two largest comparative Phase 3 clinical trials ever conducted against vancomycin in CDI. The two fidaxomicin Phase 3 clinical studies were multi-center, randomized, double-blind trials, which enrolled a total of 1,164 adult patients. Patients with confirmed CDI received either fidaxomicin (200 mg q12h) or Vancocin® (125 mg q6h), the only FDA approved product for the treatment of CDI. In both of these studies, fidaxomicin met the primary endpoint of non-inferiority of clinical cure compared to Vancocin. Importantly, in both trials fidaxomicin was statistically superior to Vancocin in reducing recurrences of CDI and in global cure rate.

About Clostridium difficile Infection (CDI)

Clostridium difficile infection (CDI), commonly referred to as "C. difficile" or "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 resulting from infection of the inner lining of the colon by C. difficile bacteria, which produce 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, thus allowing C. difficile bacteria to flourish and produce toxins.

Current therapeutic options for CDI include the off-label use of metronidazole and oral vancomycin, the latter being 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 the CDI treatment.

Primary risk factors for CDI include broad-spectrum antibiotic use (such as cephalosporins and fluoroquinolones), older age (over 65) and exposure to emerging hyper-virulent strains (BI/NAP1/027, 078, 001) of C. difficile. The increasing incidence of CDI, along with higher rates of both treatment failures and recurrences with current therapies have resulted in greater awareness and concern about CDI among medical professionals and public health officials. You may learn more about CDI at www.cdiinfo.org, a website of Optimer.

About Fidaxomicin

Fidaxomicin is the first in a new class of antibiotics called macrocycles, which inhibit the bacterial enzyme RNA polymerase, resulting in the 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, have been shown to disrupt the gut flora. Fidaxomicin facilitates the return of normal physiological conditions in the colon which may be responsible for reducing CDI recurrence rates. Optimer has filed applications in the U.S. and the EU for marketing authorization for fidaxomicin for the treatment of CDI and reducing risk of recurrence when used for treatment of initial CDI.

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 and Pruvel™ (prulifloxacin).  Fidaxomicin is a narrow spectrum antibiotic being developed for the treatment of Clostridium difficile infection (CDI).  The Company has submitted an NDA to the FDA, and filed a MAA with the European Medicines Agency (EMA) for fidaxomicin. Pruvel™ is 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 FDA's review of Optimer's NDA, including any advisory committee meetings, potential approval and commercial launch of fidaxomicin, and the incidence of 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 development efforts, the timing and status of regulatory filings, the timing and receipt of regulatory actions or approvals, Optimer's ability to successfully commercialize fidaxomicin, if approved, the development of alternative treatments for CDI, and other risks detailed in Optimer's filings with the Securities and Exchange Commission.

SOURCE Optimer Pharmaceuticals, Inc.