Optimer Pharmaceuticals has partnered with Astellas Pharma in a regional licensing deal worth US$224 M to develop and commercialise its experimental antibiotic, fidaxomicin (OPT-80), for Clostridium difficile infection. Astellas gains rights to develop and market the drug in Europe and certain countries in the Middle East, Africa and the CIS. Optimer, which will receive a welcome US$68 M upfront plus milestone payments of up to US$156 M and tiered double-digit royalties, will hope that Astellas’ expertise in anti-infectives will help maximise the commercial potential of the antibiotic.