The monoclonal antibody bezlotoxumab targets Clostridium difficile toxin B. The drug was approved in October, and a new study confirms its efficacy in preventing C. difficile recurrence. Two double-blind, randomized, placebo-controlled trials were performed on 2,655 adults receiving oral standard-of-care antibiotics for primary or recurrent C. difficile infection. Participants received bezlotoxumab infusion, actoxumab (which targets C. difficile toxin A) along with bezlotoxumab, or placebo. (In an earlier study, researchers tried actoxumab alone but discontinued the effort after an interim analysis showed it to be of no benefit.) The primary endpoint was recurrent infection within 12 weeks after infusion in the modified intention-to-treat population. In both trials, the rate of recurrent C. difficile infection was significantly lower with bezlotoxumab, 17% vs. 28% in study one, and 16% vs. 26% in study two (P < 0.001 for both). The rates of adverse events were similar across all groups. The addition of actoxumab to bezlotoxumab did not improve efficacy. The authors concluded that bezlotoxumab was associated with a substantially lower rate of recurrent C. difficile infection compared to placebo with a good safety profile (N Engl J Med 2017;376:305-317).