RBX2660 Shows Consistent Safety, Efficacy for C. Diff

New clinical trial data presented at the Digestive Disease Week meeting suggest that an investigational microbiota-based live biotherapeutic (RBX2660) leads to a consistent reduction in the risk of Clostridioides difficile recurrence when administered to various groups of patients.

In this MedPage Today video, lead author Paul Feuerstadt, MD, of Yale School of Medicine and PACT (Physicians Alliance of Connecticut) Gastroenterology Center, discusses the study findings and clinical impact.

Following is a transcript of his remarks:

So, what we presented here was a really exciting study. Because what we did was we combined the phase II study, which was a dose-ranging study where patients had two or more recurrences of C. difficile, were all receiving standard-of-care antimicrobial, and then randomized into either two doses of placebo a week apart, a dose of RBX2660 followed a week later by placebo, or two doses of RBX2660. So that was one study that was included.

And then the other, as a result of that dose-ranging study, a single dose of RBX2660 proceeded to phase III. And in that phase III, all patients had one or more recurrences of C. difficile, they all received standard-of-care antimicrobial, and then were randomized to either receive placebo or RBX2660, followed for 8 weeks for recurrence and 24 weeks or 6 months for safety.

Due to the similarity of these trials -- similar patient populations, same diagnostics, same follow-up, identical product -- it was decided that we could do a pooled analysis looking at several subgroups: including age, gender, number of previous episodes, race, ethnicity, duration of antimicrobial prior to intervention, and finally geographic site of application or geographic site of treatment.

What we did was we compared odds ratios between these subgroups to see if they differed. And overall, we found no differences, which is exactly what our hypothesis was.

There were no differences based upon any of the factors that I listed, basically stating to a clinician that yes, this works in a clinical sense from an efficacy standpoint and a broad trial. But when you look through these subgroups, you don't need to pigeonhole this group versus another group can receive this. The safety and efficacy should be consistent across those subgroups. So this can be broadly used in a general population.

For general healthcare providers, the significance of these findings is that, yes, we see an overall efficacy of the product. But what we tried to do is tease through whether there was a sweet spot for this. Perhaps people over 65 might respond better than those less than 65, maybe less than 14 days of Akne-Mycin is better than more than 14 days of Akne-Mycin.

But what we showed is regardless of the circumstance -- demographics, treatment, number of previous episodes -- this showed a very consistent efficacy. There were no differences in the odds ratios for treatment success, speaking to the fact that it makes it easier to know when to use this, you really can base it on the number of recurrences.

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