Optimer Pharmaceuticals, Inc. and Cubist Pharmaceuticals, Inc. have signed an exclusive two-year co-promotion agreement to market Dificid (fidaxomicin) in the U.S. Dificid is an antibiotic currently under review by the FDA for the treatment of Clostridium difficile infection (CDI), also known as Clostridium difficile-associated diarrhea (CDAD). The FDA is expected to complete its review by a Prescription Drug User Fee Act (PDUFA) goal date of May 30, 2011.

Optimer will be responsible for the manufacturing and distribution of Dificid in the U.S. and for recording product revenue. Optimer will also be responsible for obtaining FDA approval, and will retain ownership of the NDA. Cubist will receive $15 million per year during the two-year agreement, beginning with the first commercial sale. Cubist is also eligible to receive an additional $5 million in the first year after commercialization, and $12.5 million in the second year if sales targets are achieved. Cubist will also receive a portion of Optimer’s profits from any sales above the specified annual sales targets.

“Cubist has a proven track record and well established relations with all stakeholders involved in the antibiotics space. We believe this collaboration will maximize the impact of and de-risk Dificid’s U.S. commercial launch, assuming approval,” said Pedro Lichtinger, president and chief executive officer of Optimer. “We also believe this collaboration with Cubist will allow us to accelerate formulary adoption, and expand our market reach and penetration.”

Cubist’s president and chief executive officer Michael Bonney, said, “We believe that the strengths of Cubist’s seasoned sales force, medical affairs team and our experience in the hospital will add tremendous value to Optimer’s launch strategy and execution. We look forward to working with Optimer to introduce a much needed therapy for seriously ill patients suffering from CDAD.”