SAN DIEGO – Bezlotoxumab prevented recurrent Clostridium difficile infections (CDIs) among high-risk patients even more effectively than in the overall populations of the placebo-controlled MODIFY I and MODIFY II trials, according to a report at the annual Digestive Disease Week.
“In those key subpopulations at high risk for recurrence [of C. difficile infection], bezlotoxumab both reduced recurrence and increased rates of global cure,” said Dr. Ciaran P. Kelly of Harvard Medical School and Beth Israel Deaconess Medical Center in Boston. The biologic was especially effective among older adults and patients with at least one recent episode of CDI, Dr. Kelly and his associates found.
Dr. Ciaran P. Kelly
Bezlotoxumab is a monoclonal antibody targeting Clostridium difficile toxin B. The international, randomized, double-blind, 12-week MODIFY I and II trials included 2,656 patients with laboratory-confirmed CDI who were randomly assigned to receive either a single intravenous dose of the biologic (10 mg per kg) or placebo in addition to standard care antibiotics – that is, oral metronidazole and vancomycin; intravenous metronidazole with oral vancomycin; oral fidaxomicin; or oral fidaxomicin with intravenous metronidazole.
In both trials, bezlotoxumab was associated with a 10% decrease in rates of recurrent CDI, compared with placebo (P = .0003). Bezlotoxumab also achieved a 9.7% increase in rates of global cure, defined as clinical cure of the initial episode with no recurrence, Dr. Kelly said.
For the current analysis, he and his associates examined the efficacy of bezlotoxumab among patients at increased risk for recurrent CDI. These patients were older than 65 years, were immunocompromised, had a history of recurrent CDI, had been diagnosed with CDI within 6 months, and/or had severe CDI or were infected with hypervirulent, binary toxin positive strain. Most patients in the trials fell into at least one of these categories, Dr. Kelly said.
For each subgroup, bezlotoxumab was associated with lower rates of CDI recurrence and higher rates of global cure than in the overall study population, he emphasized. Compared with placebo, the most dramatic improvements in recurrence and global cure rates were among older patients (a 16% decrease and a 16% increase, respectively), patients with recent CDI (a 16% increase and a 12% decrease), patients with a history of recurrent CDI (a 13% decrease and a 12% increase) and immunocompromised patients (a 13% decrease and a 15% increase).
Neither trial generated a concerning safety signal, according to Dr. Kelly. There were “slight increases” in infusion reactions in the bezlotoxumab arms, but these were mostly minor and short lived, he added. “Serious adverse events were, in fact, slightly more common in the placebo group, mainly because of adverse events related to recurrence.”
The MODIFY trials were funded by Merck. Dr. Kelly reported consulting and advisory relationships with Merck, Sanofi Pasteur, Seres Therapeutics, Summit, and Alba.