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DIFICID Data Presented at American Geriatric Society Annual Meeting Demonstrates that Advancing Age is Associated with Progressive Deterioration of Treatment Outcomes in Patients with Clostridium difficile Infection

SAN DIEGO, May 12, 2011 /PRNewswire/ -- Optimer Pharmaceuticals (NASDAQ: OPTR) today announced the presentation of an additional analysis of data from the company's two Phase 3 clinical trials of DIFICID™ (fidaxomicin), an investigational antibiotic for the treatment of Clostridium difficile Infection (CDI), at the American Geriatric Society (AGS) Annual Meeting held in National Harbor, Maryland.


The analysis showed that above 40 years, advancing age was associated with decreasing odds of sustained cure, a more prolonged time to resolution of diarrhea and an increased risk of disease recurrence, independent of treatment with DIFICID or vancomycin. In addition, treatment with fidaxomicin was associated with a 54% lower risk of recurrence (p< 0.001) and a 1.9-fold greater probability of cure without recurrence (p< 0.001) in comparison to vancomycin. In the per protocol population, 999 patients treated with either DIFICID or oral vancomycin from the two DIFICID Phase 3 trials were divided into age groups defined by decades. By regression modeling, researchers determined that advancing age for each decade above the age of 40 was associated with a 17% reduction in probability of CDI cure (odds ratio or OR 0.83; p=0.008); a 17% increase in odds of recurrence within 30 days from end of therapy (OR 0.87; p<0.001); and a 13% reduction in the probability of a 30-day cure without recurrence (OR 1.17; p=0.007).

"With more than two-thirds of hospitalized patients with CDI in the U.S. being over the age of 65, advancing age has long been known as a risk factor for CDI, disease relapse and CDI-related mortality," said Thomas Louie, M.D., Professor of Medicine, Department of Medicine and Microbiology-Infectious Diseases at the University of Calgary. "This study suggests that increased risk doesn't simply start when a person turns 65. Instead, the risk gradually increases with age. With the backdrop of an aging population and widespread use of antibiotics, this progressive deterioration of CDI outcomes with age is a particularly significant public health concern."


DIFICID™ (fidaxomicin), if approved, will be the first new antibiotic for the treatment of Clostridium difficile infection (CDI) in nearly 30 years. In two Phase 3 trials for the treatment of CDI, fidaxomicin was non-inferior in clinical cure when compared to vancomycin, the only FDA approved product for CDI. DIFICID also demonstrated superiority to vancomycin in global cure, which is defined as a cure without recurrence, or a sustained cure, through the end of the follow up period. This difference was driven by DIFICID's lower rates of relapse of diarrhea following cessation of the CDI treatment.

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, defined as a relapse or re-establishment of diarrhea, 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 have resulted in greater awareness and concern about CDI among medical professionals and public health officials. You may learn more about CDI at, a website of Optimer.

About Optimer Pharmaceuticals

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, DIFICID™ (fidaxomicin) and Pruvel™ (prulifloxacin). DIFICID 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 Optimer's NDA for DIFICID, and has assigned a Prescription Drug User Fee Act (PDUFA) goal date of May 30, 2011. The Company also filed a MAA with the European Medicines Agency (EMA) for DIFICID. Pruvel™ is a prodrug in the fluoroquinolone class of antibiotics being developed as a treatment for infectious diarrhea. Additional information can be found at  


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Posted: May 2011