Merck has announced that the two pivotal Phase 3 clinical studies for bezlotoxumab, its investigational antitoxin for prevention of Clostridium difficile (C. difficile) infection recurrence, met their primary efficacy endpoint: the reduction in C. difficile recurrence through week 12 compared to placebo, when used in conjunction with standard of care antibiotics for the treatment of C. difficile. Based on these results, the company plans to submit new drug applications seeking regulatory approval of bezlotoxumab in the U.S., EU and Canada in 2015. Currently, there are no therapies approved for the prevention of recurrent disease caused by C. difficile.
Results from the studies were presented for the first time at the Interscience Conference of Antimicrobial Agents and Chemotherapy (ICAAC) and International Congress of Chemotherapy and Infection (ICC) joint meeting in San Diego, Sept. 17-21.
“Results of these studies showed that a single, one-time infusion of the antitoxin bezlotoxumab given with standard of care C. difficile antibiotic treatment significantly reduced the recurrence of C. difficile infection compared to standard of care alone, and demonstrated this benefit over a 12-week period,” said Dr. Mark Wilcox, Leeds Teaching Hospitals and University of Leeds, U.K., and a lead investigator for the studies. “These results were also demonstrated in patient subgroups known to be at high risk for C. difficile recurrence.”
Bezlotoxumab is not an antibiotic. It is a selective, fully-human, monoclonal antibody designed to neutralize C. difficiletoxin B, a toxin that can damage the gut wall and cause inflammation, leading to the symptoms of C. difficile enteritis, which include abdominal pain and watery diarrhea. Bezlotoxumab was developed by researchers at the University of Massachusetts Medical School’s MassBiologics Laboratory in conjunction with Medarex (now part of Bristol-Myers Squibb), and licensed to Merck in 2009 for development as a potential therapeutic for C. difficile infection.
“Recurrence is a major challenge with C. difficile infection, and novel approaches are needed to help prevent the cycle of C. difficile recurrence,” said Dr. Dale Gerding, professor of medicine, Loyola University Chicago Stritch School of Medicine, Maywood, Ill., and a lead investigator for the studies.