Optimer buys back rights to difimicin

USA-based biopharmaceutical firm Optimer Pharmaceuticals says that it has regained North American rights to its antibiotic difimicin (PAR-101/OPT-80) from Par Pharmaceuticals, with which it had been collaborating on the product's development. The transaction brings to a close the partnership that was first established in 2005 (Marketletters passim).

Under the terms of the buy-back deal, Optimer has paid Par a one-time fee of $20.0 million, and is obligated to make a $5.0 million milestone payment as well as to provide royalties on product sales, assuming successful commercialization. Currently, the drug is in a Phase IIb/III trial as a treatment for Clostridium difficile-associated diarrhea.