RBX2660 Reduces Risk of CDI Recurrence at Week 8

May 22, 2022
Kenny Walter

Kenny Walter is an editor with HCPLive. Prior to joining MJH Life Sciences in 2019, he worked as a digital reporter covering nanotechnology, life sciences, material science and more with R&D Magazine. He graduated with a degree in journalism from Temple University in 2008 and began his career as a local reporter for a chain of weekly newspapers based on the Jersey shore. When not working, he enjoys going to the beach and enjoying the shore in the summer and watching North Carolina Tar Heel basketball in the winter.

Recurrence commonly occurred during the first 2 weeks regardless of treatment.

RBX2660, a live microbiota therapeutic, resulted in a lower incidence rate of recurrent Clostridioides difficile infections (CDI) in data presented during Digestive Disease Week (DDW) 2022 Annual Meeting in San Diego.

A team, led by Sahil Khanna, MD, MBBS, Mayo Clinic, reported on the time to recurrence for patients who experienced CDI recurrence.

Recurrent C Difficile

Managing the growing threat of CDI is often complicated by recurrence, usually within 8 weeks of a previous C difficile episode.

However, several companies are preparing a new class of drugs called live microbiota therapeutics. This includes RBX2660, an investigational microbiota-based biotherapeutic that has shown promise in clinical trials in reducing the recurrence of CDI using a binary outcome measurement.

The Studies

The investigators examined data from the PUNCH CD3, a prospective, multicenter, randomized, double-blind, placebo-controlled phase 3 trial and PUNCH CD2, a phase 2b study.

Each patient in the study was at least 18 years with documented recurrent CDI. They also completed standard-of-care antibiotic therapy prior to treatment with RBX2660 or placebo.

The investigators defined CDI recurrence as the presence of CDI diarrhea and a positive C difficile toxin test.

They also defined time to CDI recurrence as the number of days from study treatment to the first assessment indicating a CDI event, which was presented based on the Kaplan-Meier method.


Overall, there were 262 patients from the PUNCH CD3 study, 69.1% (n = 181) were women. Each patient was randomized to receive either placebo (n = 85) or RBX2660 (n = 177).

At the 8 week mark, 37.6% (n = 32) of the placebo group and 28.8% (n = 51) of the RBX2660 had a CDI recurrence.

The time to recurrence corresponding to the 25th percentile of the KM estimate was 14 days for the placebo group and 30 days for patients treated with RBX2660.

This is consistent with the results of the PUNCH CD2 trial, where investigators found CDI recurrence occurred during the first 2 weeks regardless of treatment.

“Recurrence tended to occur earlier in participants treated with placebo compared to those treated with RBX2660 during the first month of treatment,” the authors wrote. “Participants who received RBX2660 had a lower incidence of CDI recurrence at 8 weeks compared to those who received placebo.”