Microbiome Composition Changes After C diff Treatment

The introduction of antibiotics change the microbiome, and in some cases, can lead to the development of Clostridioides difficile. The first line of treatment for this healthcare associated infection is antibiotics, which leads to a continuation of antimicrobials into the gastrointestinal tract and can continue to influence the gut microbiota—sometimes negatively.

Unsuccessful treatment or recurrence of C diff (rCDI) can happen to some patients and develop into ongoing health issues and quality-of-life challenges that can be a continuous cycle that becomes difficult to overcome.

As an alternative, biopharmaceutical companies have developed other C diff therapeutics not utilizing antimicrobials. Specifically, live biotherapeutic products (LBPs) may shift the composition and diversity of a recipient’s gut microbiome to suppress Clostridioides difficile outgrowth and recurrent C diff infection.

One example of this newer therapeutic is Ferring’s fecal microbiota, live-jslm (FMBL; Rebyota), which was FDA approved last fall for the indication of rCDI in adult patients.

Rebyota’s phase 3 trial, PUNCH CD3, looked at the biotherapeutic vs placebo in seeing how it influenced the participants’ microbiomes. After completing antibiotic therapy for the enrolling CDI episode, participants received a single, blinded dose of Rebyota (RBL) or placebo administered rectally.

This study, “Significant and Durable Microbiome Compositional Changes and Clonal Engraftment in a Phase 3 Trial of Fecal Microbiota, Live-jslm for Recurrent Clostridioides difficile Infection,” was presented at the 2023 MAD-ID Annual Antimicrobial Stewardship Meeting.

According to the investigators, at baseline, responders’ microbiomes differed with Gammaproteobacteria and Bacilli being predominant. Bacteroidia and Clostridia are typically predominant in healthy populations.

A median of 10 different species were clonally engrafted from RBL into participants at 1 week after treatment, according to the study authors, and detected engraftment persisted to at least 6 months (median=14 engrafting species; maximum=62 engrafting species).

The introduction of the therapeutic was immediate. “Gut microbiome composition shifts were detected as early as 1 week after RBL treatment and sustained for at least 6 months after treatment,” the investigators wrote.

In conclusion, the authors said post treatment changes were characterized by increased Bacteroidia and Clostridia and decreased Gammaproteobacteria and Bacilli.