Microbiota-Based Biotherapeutic Drug Reduces Recurrent C. difficile Infections

After 6 months following treatment, 90.5% (38 of 42) responders to RBX2660 remained recurrence-free, whereas 85% (17 of 20) patients in the placebo group remained recurrence-free.

Patients with recurrent Clostridioides difficile (C. difficile) infection treated with investigational, microbiota-based, live biotherapeutic RBX2660 experienced a reduction in recurrent infections, according to study results presented at the American College of Gastroenterology (ACG) 2022 Annual Meeting, held from October 21 to 26, 2022, in Charlotte, North Carolina, and virtually.

Guideline recommendations suggest gut microbiome restoration using fecal microbiota transplantation in patients with 2 or more recurrent C. difficile infections. Adapting the concept of fecal microbiota transplantation, RBX2660, delivers a wide spectrum of live microbiota to the gut to minimize the likelihood of continued recurrent C. difficile infections.

Researchers in the US conducted a post hoc analysis of the prospective, multicenter, randomized, double-blind, placebo-controlled, phase 3 trial, Microbiota Restoration Therapy for Recurrent Clostridium Difficile Infection (PUNCH CD3; ClinicalTrials.gov Identifier: NCT03244644), in which they studied the efficacy and safety of RBX2660, in treating recurrent C. difficile infections.

The researchers enrolled 86 patients following their first recurrent infection, which had been treated with standard-of-care antibiotic therapy. They randomly divided these 86 patients with a second recurrent C. difficile infection into 2 groups, 53 into the treatment group and 33 into the placebo group. The treatment group received a single dose of RBX2660.

After 8 weeks following treatment, 79.2% (42 of 53) patients treated with RBX2660 remained free of C. difficile infection recurrence compared with 60.6% (20 of 33) of patients in the placebo group.

Similarly, after 6 months following treatment, 90.5% (38 of 42) of responders to RBX2660 remained recurrence-free, whereas 85% (17 of 20) of patients in the placebo group remained recurrence-free.

In the treatment group, 54.7% (29 of 53) of patients experienced treatment-related adverse events during the 8-week period compared with 33.3% (11 of 33) of patients in the placebo group. Most adverse events were mild, gastrointestinal side effects. Only 5.7% (3 of 53) of patients in the treatment group reported serious adverse events compared with 6.1% (2 of 33) in the placebo group; however, no adverse events resulted in death or discontinuation of the treatment.

“RBX2660-treated patients had numerically higher treatment success at week 8 and sustained response at 6 months compared to placebo,” the researchers stated. “These results support the efficacy and safety of RBX2660 in reducing rCDI [recurrent C difficile infections].”

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.


Khanna S, Tillotson G, Ando M, et al. Efficacy and safety of RBX2660 in patients after first recurrence of Clostridioides difficile infection – results from a phase 3, randomized, placebo-controlled study. Abstract presented at: ACG 2022 Annual Meeting; October 21 to 26, 2022; Charlotte, NC. Abstract D0100.

This article originally appeared on Gastroenterology Advisor.