A microbiota-based live biotherapeutic for treating recurrent Clostridioides difficile infection (rCDI) remained effective after subsequent antibiotic exposure, researchers reported this week in Open Forum Infectious Diseases.
In a post-hoc analysis of a phase 2 trial evaluating the safety, efficacy, and durability of Rebyota fecal microbiota transplantation for preventing rCDI, the researchers evaluated patients who received non-CDI antibiotics for up to 2 years after Rebyota administration. Although Rebyota has been found to be highly effective in preventing rCDI and was approved by the US Food and Drug Administration in December 2022, the researchers wanted to assess the durability of the treatment response, particularly in patients subsequently exposed to antibiotics, which can disrupt the gut microbiome and increase the risk of rCDI. They looked specifically at non-CDI antibiotics, because any recurrence of CDI would require antibiotic treatment.
Treatment response was defined as the absence of CDI diarrhea needing retreatment as of the last evaluable time point (8 weeks, 6 months, 1 year, or 2 years) after Rebyota administration.
Durable response
Of the 149 participants in the trial, 43 received non-CDI antibiotics after Rebyota administration over a 2-year period. Across all evaluable time points, 37 of 43 (86%) had treatment response regardless of when non-CDI antibiotic exposure occurred, with treatment response rates ranging from 83% to 96% at the various time points.
Among participants with treatment response, success was sustained for a median of 470 days from the first initial non-CDI antibiotic use. Of the six participants who experienced rCDI, 5 received a high-risk antibiotic.
Although the study was limited by lack of a control group and other factors, the researchers say the findings provide evidence that Reboyota offers durable protection after antibiotic exposure in a real-world population.
"Irrespective of the inherent limitations of this analysis, these results suggest RBL [Rebyota] may restore the gut microbiota to a sufficient threshold protective against rCDI for many patients despite subsequent non-CDI antibiotic use," they wrote.