RBX2660 Prolongs Time to Recurrence in Patients with CDI Infection

Patients who took RBX2660 following antibiotic therapy had lower rates of recurrence and double the time to recurrence, compared to patients taking placebo.

Ferring Pharmaceuticals’ investigational Clostridioides difficile infection (CDI) therapy delays recurrence in patients with a history of repeat infections, according to newly released data.

The new data were presented at the American Gastroenterological Association’s Digestive Disease Week 2022, which was held in San Diego. The report showed that RBX2660, an investigational microbiota-based live biotherapeutic, led to lower rates of recurrence among patients treated with standard-of-care antibiotics followed by RBX2660, compared to those treated with antibiotics followed by placebo. However, it also showed that time to recurrence among those who recurred was more than twice as long in patients who were given the therapeutic rather than placebo.

Paul Feuerstadt, MD, of PACT Gastroenterology Center, in Connecticut, explained that the new findings are based on data from the PUNCH CD3 trial, a placebo-controlled phase 3 trial testing RBX2660 in patients with documented recurrent CDI who had already undergone standard antibiotic treatment.

“Within that abstract, they looked at 262 patients enrolled in the PUNCH CD3 trial, and they drew a Kaplan-Meier curve for time to recurrence,” explained Feuerstadt, who has studied RBX2660 but was not an author of the time-to-recurrence study. “The time to recurrence in the placebo arm, the median 25th percentile, was 14 days versus 30 days in the RBX2660 arm.”

Feuerstadt said the findings are significant for a couple of reasons. First, they give insights into the timing of recurrences. He said most of the existing scientific evidence suggests that recurrences are most likely to happen within the first month. The new data support that timeline. However, Feuerstadt said the study also shows the impact of RBX2660 on recipients’ metabolisms.

“What that tells me is that progress was made,” he said. “The metabolic environment did have progress.”

Feuerstadt said the study affirms that the intervention of RBX2660 led to improvements in patients’ metabolic milieu which in turn lowered the patients’ susceptibility to recurrence.

“In the placebo environment, that milieu wasn't created or wasn't fortified,” he said. “Therefore, the time to recurrence was shorter, whereas the time to recurrence in the RBX2660 arm was almost two weeks longer, meaning that the environment was created, but it might not have been enough to sustain the effect.”

The study data included 8 weeks of follow-up, by which time 32 of 85 patients in the placebo arm (37.6%) and 51 of 177 patients in the RBX2660 arm (28.8%) had experienced recurrence. Though those figures reinforce the superiority of RBX2660 versus placebo, Feuerstadt said the data could also help direct future research into how to further lower the recurrence rate.

“So that really speaks to maybe future studies where we might refortify that in patients that might be at greater risk for recurrence,” he said, “although single dosing—single rectal installation—seems to be the optimal dose.”

RBX2660 has been studied for nearly a decade, including more than 6 controlled clinical trials and more than 1000 participants, according to Ferring. The drug has been granted Fast Track, Orphan, and Breakthrough Therapy designations by the Food and Drug Administration.