OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, safety, and 
place in therapy of bezlotoxumab (BEZ), a novel monoclonal antibody against 
Clostridium difficile toxin B.
DATA SOURCES: A PubMed search was conducted for data between 1946 and April 2017 
using MeSH terms bezlotoxumab, MK-6072, or MDX-1388 alone and the terms 
Clostridium difficile combined with monoclonal antibody or antitoxin.
STUDY SELECTION AND DATA EXTRACTION: The literature search was limited to 
English-language studies that described clinical efficacy, safety, and 
pharmacokinetics in humans and animals. Abstracts featuring prepublished data 
were also evaluated for inclusion.
DATA SYNTHESIS: BEZ is indicated for adult patients receiving standard-of-care 
(SoC) antibiotics for C difficile infection (CDI) to prevent future recurrence. 
Two phase III trials-MODIFY I (n = 1452) and MODIFY II (n = 1203)-demonstrated a 
40% relative reduction in recurrent CDI (rCDI) with BEZ compared with placebo 
(16.5% vs 26.6%, P < 0.0001). The most common adverse drug events associated 
with BEZ were mild to moderate infusion-related reactions (10.3%).
CONCLUSIONS: In patients treated with SoC antibiotics, BEZ is effective in 
decreasing rCDI. BEZ has no apparent effect on treatment of an initial CDI 
episode. In light of increasing rates of CDI, BEZ is a promising option for 
preventing recurrent episodes. The greatest benefit has been demonstrated in 
high-risk patients, though the targeted patient population is yet to be defined.