C. diff. Infection, Renal Impairment Have Lower Risk of Recurrence if Given Bezlotoxumab

Patients with renal impairment appear to be at a higher risk of recurrent Clostridium difficile infection (rCDI), but the risk can be lowered if the patients are prescribed bezlotoxumab.

The study, published in the journal Open Forum Infectious Diseases, sheds new light on the apparent link between renal impairment and rCDI.

Clostridium difficile infection (CDI) is a common cause of diarrhea in adults, but it can be effectively treated with antibiotics. However, a significant minority of patients treated with antibiotics will eventually see a recurrence of the infection, and among those who face a recurrence, about 40% will experience at least 2 additional recurrences.

Corresponding author Yoav Golan, MD, MS, of Tufts University Medical Center, and colleagues wrote that the novel interventions used to combat rCDI tend to be costly, thus creating a need for physicians to better predict which patients might be at high risk of recurrence. Earlier research has suggested that renal impairment might be an important identifier of patients at particular risk of recurrence. Golan and co-authors sought to build upon that research by studying not only links between renal impairment and rCDI, but also the impact of the anti-Toxin B monoclonal antibody bezlotoxumab on these patients.

The authors pooled data from two phase 3 clinical trials, in which patients received either bezlotoxumab or placebo for CDI. Both trials were randomized, double-blind, and multicenter trials. The goal was to assess the association between renal impairment and rCDI in patients who received placebo, and then to compare those data with rates of rCDI in patients receiving placebo versus those who received bezlotoxumab.

Within the two pooled studies, 919 patients with CDI reported renal impairment, and 612 had CDI without renal impairment. Among those with renal impairment, the rate of recurrence within 12 weeks was 36.6%, versus a recurrence rate of 27.7% among those without renal impairment. In fact, in the placebo group, the rate of recurrence among patients whose only risk factor was renal impairment was 28.8%. Among patients who did not have renal impairment and did not have any other risk factors, the rate of recurrence was just 12.5%.

As for the impact of bezlotoxumab, the investigators found similarly significant results. Among patients with renal impairment, those who were treated with bezlotoxumab had a recurrence rate of 19.5%, but those given placebo had a recurrence rate of 36.6%.

Golan told Contagion the study did not delve into the question of whether the extent of renal impairment impacted the risk of recurrence, though he said there “could well be” a link. Such a question would require further research, however, he said.

For now, Golan said this latest study suggests bezlotoxumab reduces risk of rCDI, just as earlier research has shown fidaxomicin can do the same. However, both drugs also come with high price tags. In a world of antibiotic stewardship and an increased focus on cost-effectiveness, Golan said the question facing many doctors is what factors identify high-enough risk of recurrence to justify the use of a high-cost drug like bezlotoxumab or fidaxomicin.

“My recommendation is to label any patient with C. diff. And any degree of renal dysfunction as being at high-enough risk of CDI recurrence and treat them with an agent that reduces recurrence,” he said.