A vital recent therapeutic for C. difficile infection based on discoveries at UMass Medical School is going to be submitted for regulatory approval on the basis of the results of clinical studies carried out by the international pharmaceutical company Merck.

In an announcement, Merck said two key Phase 3 clinical studies for a monoclonal antibody licensed from UMass Medical School's MassBiologics had reached their primary efficacy endpoint. The studies showed reduction in C. difficile recurrence through week 12 in comparison to placebo, when used in conjunction with standard of care antibiotics to treat C. difficile.

The company, on the basis of results, is looking forward to submit new drug applications requesting for regulatory approval of the monoclonal antibody, known as bezlotoxumab, in the United States, the European Union and Canada in 2015. At present, there are no approved therapies for the prevention of recurrent disease caused by C. difficile.

Researchers at MassBiologics in conjunction with Medarex (now part of Bristol-Myers Squibb) developed Bezlotoxumab. In 2009, it was licensed to Merck for development as a potential therapeutic for C. difficile infection.

The study results were presented for the first time on September 20 at the Interscience Conference of Antimicrobial Agents and Chemotherapy and International Congress of Chemotherapy and Infection (ICC) joint meeting in San Diego.

Mark Wilcox, MD, Leeds Teaching Hospitals and University of Leeds, UK, and a lead investigator for the studies, said, "Results showed that a single, one-time infusion of antitoxin bezlotoxumab given with standard of care C. difficile antibiotic treatment significantly reduced recurrence of C. difficile infection compared to standard of care alone, and demonstrated this benefit over a 12-week period".

Mark added that the results of these studies were also demonstrated in patient subgroups, which are known to be at high risk for C. difficile recurrence.