Rib-X Pharmaceuticals has initiated a Phase IIb clinical trial to evaluate delafloxacin as a treatment of acute bacterial skin and skin structure infections, as well as infections caused by MRSA.

The trial will evaluate multiple objective efficacy measures to support the design of the Phase III clinical studies.

The randomised and double-blind study will evaluate delafloxacin versus linezolid and vancomycin using objective efficacy measures to assess relative clinical responses in subjects with acute bacterial skin and skin structure infections.

The trial will enrol 240 subjects at multiple centres in the US, who will be randomised into three equal-sized treatment cohorts to receive either delafloxacin 300mg every 12 hours, or the recommended doses of linezolid or vancomycin.

The primary endpoints of the study are to assess the relative clinical response to delafloxacin, linezolid, and vancomycin.

Delafloxacin, a novel fluoroquinolone antibiotic candidate that offers both intravenous and oral versatility, has successfully completed three Phase II clinical trials.