OPT-80, a macrocyclic antimicrobial agent for the treatment of Clostridium difficile infections:: a review

Background: Clostridium difficile-associated diarrhoea has become a major problem over the last years. Increasing incidence and more severe clinical cases initiated the search for new treatment options. Objective: OPT-80, also known as tiacumicin B, lipiarmycin or PAR-101, is a macrocyclic antimicrobial with little or no systemic absorption after oral administration and narrow activity spectrum against Gram-positive aerobic and anaerobic bacteria. Methods: Data on OPT-80 available from published studies, presentations at conferences and the manufacturer were collected and reviewed. Results/conclusion: The in vitro studies of OPT-80 and clinical C difficile strains showed high activity at low concentrations. Safety and efficacy of the drug were found to be favourable. More Phase II and III clinical trials are to be completed.