A phase 3 clinical trial found that SER-109, an investigational microbiome therapeutic for the treatment of recurrent Clostridioides difficile infection (CDI), was well tolerated and showed clinical benefit in a population with prevalent comorbidities, researchers reported today in JAMA Network Open.
The single-arm ECOSPOR IV trial was conducted among two cohorts of adults who had a history of recurrent CDI: rollover patients from the ECOSPOR III trial who had a CDI recurrence within 8 weeks of receiving either SER-09—a therapeutic composed of Firmicutes bacterial spores—or placebo, and patients with at least one CDI recurrence.
Patients in both cohorts received four SER-109 capsules daily for 3 days following symptom resolution after initial antibiotic treatment. The main outcomes were safety, measured as the rate of treatment-emergent adverse events (TEAEs), and cumulative rates of recurrent CDI through week 24. A total of 263 patients were enrolled from October 2017 to April 2022, with 29 in cohort 1 and 234 in cohort 2. Comorbidities were prevalent in the overall population.
Overall, 141 patients (53.6%) had TEAEs, which were mostly mild and gastrointestinal; none of the 8 deaths or 33 serious TEAEs were considered treatment-related. Just 23 patients (8.7%) had recurrent CDI at week 8 and 36 (13.7%) at week 24. Analysis by select baseline characteristics showed consistent low rates of recurrent CDI up to week 8 in all subgroups, but rates were lower in patients younger than 65 years compared with those 65 and older (4.0% vs 13.1%) and in patients enrolled based on positive polymerase chain reaction results versus those with positive toxin enzyme immunoassay results (4.3% vs 10.4%).
These data support an important role for SER-109 as part of a paradigm shift.
The investigators say the combined safety data from this trial and efficacy data from the ECOSPOR III trial, which demonstrated the superiority of SER-109 compared with placebo in reducing CDI recurrence, suggest that the use of purified Firmicutes spores benefits patients with recurrent CDI.
"These data support an important role for SER-109 as part of a paradigm shift in the clinical management of recurrent CDI," they wrote.