FDA Advisory Committee recommends Zinplava (bezlotoxumab injection) for treatment of Clostridium difficile infection recurrence.- Merck Inc.

The FDA's Antimicrobial Drugs Advisory Committee voted 10 to 5, with 1 abstention, to recommend Zinplava ( bezlotoxumab injection) from Merck Inc., for the prevention of Clostridium difficile infection (CDI) recurrence in patients aged 18 years or older. Bezlotoxumab is a fully human monoclonal IgG1/kappa antibody that binds to and neutralizes C difficile toxin B, likely by preventing it from binding to colonic cells and causing their inflammation. Bezlotoxumab is administered intravenously (IV) as a single dose of 10 mg/kg over 1 hour. Zinplava is given in conjunction with standard of care antibiotics that are used in the treatment of C. difficile infection. It is not an antibiotic.

The decision follows a discussion of data from several trials including two phase III trials (Studies P001 and P002). Both studies were randomized, multicenter, double-blind, placebo-controlled trials of patients aged at least 18 years with a confirmed diagnosis of CDI. The clinical trial process was complicated by the fact that early in the development process the company hypothesized that actoxumab, an antitoxin A antibody, would also prevent recurrence of CDI, and that the two drugs together might be even more effective.

Comment: Treatment with the combination of bezlotoxumab and actoxumab did not provide added efficacy over bezlotoxumab alone. Furthermore, actoxumab alone provided no benefit in the prevention of C. difficile recurrence compared with placebo. Based on these results, bezlotoxumab alone was selected for the marketing authorization application.