Bezlotoxumab for the treatment of Clostridium difficile-associated diarrhea.

Diarrhea caused by Clostridium difficile is one of the major emerging threats to modern healthcare systems worldwide. Although C. difficile spores are present in the gut innocuously, because of repeated broad-spectrum antibiotic therapy, the spores germinate with concomitant release of exotoxin A and B, resulting in mild to severe diarrhea. Antibiotic therapy is augmented by addition of the humanized antibodies actoxumab and bezlotoxumab to prevent the action of exotoxins A and B, respectively, since they provide passive immunity. Bezlotoxumab, a fully humanized monoclonal antibody developed against C. difficile toxin B, was approved by the U.S. Food and Drug Administration in 2016 to prevent the recurrence of C. difficile infections (CDI) in patients above 18 years of age who are receiving antibiotics for CDI and are at a higher risk of recurrence.