Optimer Pharmaceuticals, Inc.,  a global biopharmaceutical company, and Tokyo-based Astellas Pharma Inc. has entered an exclusive collaboration and license agreement to develop and commercialize fidaxomicin tablets in Japan for the treatment of Clostridium difficile Infection (CDI).

In return for the exclusive license to fidaxomicin in Japan, Optimer is entitled to receive a one-time, up-front cash payment of US$ 20 million from Astellas. Optimer is also eligible to receive additional cash payments of up to US$ 70 million upon the achievement of certain regulatory and commercial milestones. Optimer is further entitled to receive payments from Astellas that provide a return resulting in a double digit percent of Astellas net sales in the territory. Astellas is responsible for all future costs associated with the development and commercialization of fidaxomicin in Japan.

“We are pleased to have entered a collaboration with Optimer to introduce fidaxomicin to Japan for the treatment of CDIs,” said Yoshihiko Hatanaka, president and CEO of Astellas Pharma Inc. “We believe that fidaxomicin's highly differentiated clinical profile, which has been confirmed by clinical studies conducted in the US and EU, has the potential to provide a new and unique treatment option for patients in Japan. Astellas is committed to a focus on infectious diseases, and this collaboration is an important milestone for our franchise.”

“Astellas is a leader in the anti-infective market in Japan. Leveraging their expertise efficiently helps realize the potential of fidaxomicin to meet the serious unmet needs of CDI patients in Japan, helping to address the risk of recurrence inherent in the disease, while optimizing the market opportunity for our shareholders,” said Pedro Lichtinger president and CEO, Optimer. “Japan is a key territory we have prioritized for geographic market expansion and complements nearer term market opportunities in the US, Canada and the European Union as we continue to pursue additional international market opportunities.”

In 2011, Optimer entered into a commercial partnership with Astellas Pharma Europe Ltd. to develop and market fidaxomicin under the trade name DIFICLIR in Europe and certain other countries in the Middle East, Africa and the Commonwealth of Independent States. The European Medicines Agency granted marketing authorization to DIFICLIR in December 2011, and Astellas Pharma Europe Ltd. expects to begin selling DIFICLIR in the first of its territories starting in 2012.

Fidaxomicin is approved by the US Food and Drug Administration (FDA) for the treatment of Clostridium difficile-associated diarrhea (CDAD) in adults 18 years of age or older in the United States under the trade name DIFICID.

CDI has become 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 diarrhoea and, in the most serious cases, death. 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.

DIFICID 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 haemorrhage (4%), anaemia (2%), and neutropenia (2%).

Astellas Pharma Inc., is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceutical products.

Optimer Pharmaceuticals, Inc. is a global biopharmaceutical company focused on discovering, developing and commercializing innovative hospital specialty products that have a positive impact on society.