Bezlotoxumab: an emerging monoclonal antibody therapy for prevention of recurrent Clostridium difficile infection

Clostridium difficile infection (CDI) is the most common health care-acquired infection associated with high hospital expenditures. The incidence of subsequent recurrent CDI increases with prior episodes of CDI, 15%–35% risk after primary CDI to 35%–65% risk after the first recurrent episode. Recurrent CDI is one of the most challenging and a very difficult to treat infections. Standard guidelines provide recommendations on treatment of primary CDI. However, treatment choices for recurrent CDI are limited. Recent research studies have focused on the discovery of newer alternatives for prevention of recurrent CDI targeting prime virulence factors involved in C. difficile pathogenesis. Bezlotoxumab is a human monoclonal antibody directed against C. difficile toxin B. Multiple in vitro and in vivo animal studies have demonstrated direct binding of bezlotoxumab to C. difficile toxin B preventing intestinal epithelial damage and colitis. Furthermore, this monoclonal antibody mediates early reconstitution of gut microbiota preventing risk of recurrent CDI. Randomized placebo-controlled trials showed concomitant administration of a single intravenous dose of 10 mg/kg of bezlotoxumab, in patients on standard-of-care therapy for CDI, had no substantial effect on clinical cure rates but significantly reduced the incidence of recurrent CDI (~40%). It shows efficacy against multiple strains, including the epidemic BI/NAP1/027 strain. Bezlotoxumab is a US Food and Drug administration-approved, safe and well-tolerated drug with low risk of serious adverse events and drug–drug interactions. Bezlotoxumab has emerged as a novel dynamic adjunctive therapy for prevention of recurrent CDI. Further studies on real-world experience with bezlotoxumab and its impact in reducing rates of recurrent CDI are needed.