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Treatment for Clostridial Infection

Update: Dificid (fidaxomicin) Now FDA Approved - May 27, 2011

Optimer Pharmaceuticals Completes New Drug Application for Fidaxomicin and Requests Priority Review From FDA

SAN DIEGO, Nov. 30, 2010 /PRNewswire-FirstCall/ -- Optimer Pharmaceuticals, Inc. today announced that it has completed the submission of its New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for fidaxomicin to treat patients with Clostridium difficile infection (CDI) and to prevent recurrences of CDI. It is the most common cause of diarrhea in the hospital, and according to the CDC contributes to 15,000-30,000 deaths each year, a number that surpasses Methicillin-resistant Staphylococcus aureus (MRSA).

"This NDA filing is one of the most significant achievements in the history of Optimer," said Pedro Lichtinger, President and CEO of Optimer. "This submission is the culmination of many years of dedicated work by the Optimer team, as well as the efforts of our clinical trial investigators and advisors to bring this much needed therapy to CDI patients. We believe fidaxomicin represents a major advance in CDI treatment, and every step we move closer to the possibility of it reaching patients is meaningful to those who are impacted by the disease."

Optimer has also requested priority review, which if granted could lead to an approval decision from the FDA in the second quarter of 2011. Fidaxomicin received Fast Track designation from the FDA in 2003 for the treatment of CDI, which allowed the Company to initiate a rolling NDA submission.

In August 2010, the Company's Marketing Authorization Application (MAA) filing for fidaxomicin was accepted for review by the European Medicines Agency.

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 global cure rate and reduced CDI recurrences by 47%. 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 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. Optimer has filed applications in the U.S. and the EU for marketing authorization for fidaxomicin for the treatment of CDI and for the prevention of recurrences.

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 EMA (Europe) 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

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 development of fidaxomicin, Optimer's plans with respect to NDA submissions, anticipated timing of the FDA's review Optimer's NDA submissions, the incidence and effects of CDI, the efficacy of current CDI treatments and the efficacy and potential benefits of fidaxomicin, and potential regulatory approval of fidaxomicin. Words such as "believes", "would", "anticipates", "plans", "expects", "may", "intend", "will", 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 development of alternative treatments for or means of preventing CDI, whether regulatory authorities will review or approve Optimer's applications for marketing approval within Optimer's anticipated timelines or at all, the timing of any marketing approvals, Optimer's ability to complete its NDA submissions 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.


Optimer Pharmaceuticals, Inc.

Christina Donaghy, Corporate Communications Manager

John D. Prunty, Chief Financial Officer & VP Finance


Canale Communications, Inc.

Jason I. Spark, Senior Vice President


SOURCE Optimer Pharmaceuticals, Inc.

Posted: November 2010

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