CDI is the most frequent cause of health care-associated infectious diarrhea in industrialized countries. It is a significant medical problem in hospitals, long-term care facilities and in the community. CDI 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. Clostridium difficile-associated diarrhea (CDAD) is the most common symptom of CDI. Patients typically develop CDI from the use of broad-spectrum antibiotics that disrupt normal gastrointestinal (gut) flora, possibly allowing C. difficile bacteria to flourish. Older patients in particular are at risk for CDI, potentially because of a weakened immune system or the presence of underlying disease. Approximately two-thirds of CDI patients are 65 years of age or older. Historically, approximately 20% to 30% of CDI patients who initially respond to treatment experience a clinical recurrence.About DIFICID® (fidaxomicin) TabletsDIFICID is the first antibacterial drug indicated for Clostridium difficile-associated diarrhea (CDAD) to be approved in more than 25 years in the U.S. It is indicated in the U.S. for the treatment of CDAD in adults 18 years of age or older. DIFICID is administered in 200 mg tablets given orally twice daily. Important Safety Information for DIFICIDDIFICID should not be used for systemic infections. Only use DIFICID for infection proven or strongly suspected to be caused by C. difficile. Prescribing DIFICID in the absence of a proven or strongly suspected C. difficile infection is unlikely to provide benefit to the patient and increases the risk of the development of drug resistant bacteria. The most common adverse reactions are nausea (11%), vomiting (7%), abdominal pain (6%), gastrointestinal hemorrhage (4%), anemia (2%) and neutropenia (2%). Please visit www.DIFICID.com or call 855-DIFICID (343-4243) for full prescribing information for DIFICID. About Optimer PharmaceuticalsOptimer Pharmaceuticals, Inc. is a global biopharmaceutical company focused on developing and commercializing innovative hospital specialty products that have a positive impact on society. Optimer developed DIFICID® (fidaxomicin) tablets, an FDA-approved antibacterial drug for the treatment of adult patients with Clostridium difficile-associated diarrhea (CDAD) and is commercializing DIFICID in the US and Canada. Optimer also received marketing authorization for fidaxomicin tablets in the European Union where its partner, Astellas Pharma Europe, is commercializing fidaxomicin under the trade name DIFICLIR™. The company is exploring marketing authorization in other parts of the world where C. difficile has emerged as a serious health problem, including Asia. Additional information can be found at http://www.optimerpharma.com.