Trading Halted Today in Optimer Pharmaceuticals Stock

SAN DIEGO, April 5, 2011 /PRNewswire/ -- Optimer Pharmaceuticals, Inc. (Nasdaq: OPTR) announced today that NASDAQ has halted trading of the Company's common stock this morning.  The Anti-Infective Drugs Advisory Committee (AIDAC) of the U.S. Food and Drug Administration (FDA) is scheduled to meet today to review and discuss Optimer's New Drug Application (NDA) for fidaxomicin for the treatment of Clostridium difficile infection.

(Logo: http://photos.prnewswire.com/prnh/20090413/LA97352LOGO)

Fidaxomicin is a narrow spectrum antibiotic being developed for the treatment of Clostridium difficile infection (CDI). In two Phase 3 trials for the treatment of CDI, fidaxomicin was equally effective in clinical cure when compared to vancomycin, the only FDA approved product for CDI.  Importantly, fidaxomicin reduced the risk of recurrence by 47% compared to vancomycin. The New England Journal of Medicine has published results from the first Phase 3 trial in an article titled, "Fidaxomicin versus Vancomycin for Clostridium difficile Infection," which appeared in the February 3, 2011 issue.  Optimer filed a marketing application in the EU for fidaxomicin for the treatment of CDI and reducing risk of recurrence when used for treatment of initial CDI.  

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 rise in incidence of CDI, along with high rates of both treatment failures and recurrences with current therapies has 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 Optimer

Optimer Pharmaceuticals, Inc. is a biopharmaceutical company focused on discovering, developing and commercializing innovative hospital specialty products that have a positive impact on society. 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 FDA granted the Company's request for six-month Priority Review of fidaxomicin, and has assigned a Prescription Drug User Fee Act (PDUFA) goal date of May 30, 2011. The Company also filed a Marketing Authorization Application (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.

Contacts

Optimer Pharmaceuticals, Inc.
Christina Donaghy, Corporate Communications Manager
John D. Prunty, Chief Financial Officer & VP Finance
858-909-0736

Canale Communications, Inc.
Jason I. Spark, Senior Vice President
619-849-6005

SOURCE Optimer Pharmaceuticals, Inc.