Safety and Tolerability of SER-109 as an Investigational Microbiome Therapeutic in Adults With Recurrent Clostridioides difficile Infection: A Phase 3, Open-Label, Single-Arm Trial.

Matthew D Sims, Sahil Khanna, Paul Feuerstadt, Thomas J Louie, Colleen R Kelly, Edward S Huang, Elizabeth L Hohmann, Elaine E L Wang, Caterina Oneto, Stuart H Cohen, Charles S Berenson, Louis Korman, Christine Lee, Bret Lashner, Colleen S Kraft, Mayur Ramesh, Michael Silverman, Darrell S Pardi, Ananya De, Asli Memisoglu, David A Lombardi, Brooke R Hasson, Barbara H McGovern, Lisa von Moltke

Journal: JAMA network open 2023;6(2):e2255758

PMID: 36780159

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Plain Language Summary

Clostridioides difficile infection (CDI) is most commonly caused by treatment with broad-spectrum antibiotics. Antibiotic treatment of CDI is generally successful but recurrences of CDI occur in 15-25% of patients after the first episode, and up to 40% of patients with a previous recurrence. This is thought to be due to persistent microbiome disruption, including a depletion of Firmicutes bacteria. The aim of this single-arm, open-label trial was to evaluate the safety and effectiveness of an investigational, microbiome therapeutic composed of purified Firmicutes spores (SER-109) to prevent CDI recurrences. 263 patients were enrolled in the study and received SER-109 on 3 consecutive days, started within 4 days of completion of antibiotic treatment for CDI recurrence. Follow-up was 24 weeks. Most patients were aged 65 years or older and had a high prevalence of comorbidities. There were no reports of serious adverse events which were considered related to SER-109. By week 24, 36 patients (13.7%) had experienced a CDI recurrence. This was independent of demographics, type of antibiotic treatment and number of prior recurrences. The authors concluded that the data suggest a role of SER-109 in the management of recurrent CDI.

Abstract

IMPORTANCE

A safe and effective treatment for recurrent Clostridioides difficile infection (CDI) is urgently needed. Antibiotics kill toxin-producing bacteria but do not repair the disrupted microbiome, which promotes spore germination and infection recurrence.

OBJECTIVES

To evaluate the safety and rate of CDI recurrence after administration of investigational microbiome therapeutic SER-109 through 24 weeks.

DESIGN, SETTING, AND PARTICIPANTS

This phase 3, single-arm, open-label trial (ECOSPOR IV) was conducted at 72 US and Canadian outpatient sites from October 2017 to April 2022. Adults aged 18 years or older with recurrent CDI were enrolled in 2 cohorts: (1) rollover patients from the ECOSPOR III trial who had CDI recurrence diagnosed by toxin enzyme immunoassay (EIA) and (2) patients with at least 1 CDI recurrence (diagnosed by polymerase chain reaction [PCR] or toxin EIA), inclusive of their acute infection at study entry.

INTERVENTIONS

SER-109 given orally as 4 capsules daily for 3 days following symptom resolution after antibiotic treatment for CDI.

MAIN OUTCOMES AND MEASURES

The main outcomes were safety, measured as the rate of treatment-emergent adverse events (TEAEs) in all patients receiving any amount of SER-109, and cumulative rates of recurrent CDI (toxin-positive diarrhea requiring treatment) through week 24 in the intent-to-treat population.

RESULTS

Of 351 patients screened, 263 were enrolled (180 [68.4%] female; mean [SD] age, 64.0 [15.7] years); 29 were in cohort 1 and 234 in cohort 2. Seventy-seven patients (29.3%) were enrolled with their first CDI recurrence. Overall, 141 patients (53.6%) had TEAEs, which were mostly mild to moderate and gastrointestinal. There were 8 deaths (3.0%) and 33 patients (12.5%) with serious TEAEs; none were considered treatment related by the investigators. Overall, 23 patients (8.7%; 95% CI, 5.6%-12.8%) had recurrent CDI at week 8 (4 of 29 [13.8%; 95% CI, 3.9%-31.7%] in cohort 1 and 19 of 234 [8.1%; 95% CI, 5.0%-12.4%] in cohort 2), and recurrent CDI rates remained low through 24 weeks (36 patients [13.7%; 95% CI, 9.8%-18.4%]). At week 8, recurrent CDI rates in patients with a first recurrence were similarly low (5 of 77 [6.5%; 95% CI, 2.1%-14.5%]) as in patients with 2 or more recurrences (18 of 186 [9.7%; 95% CI, 5.8%-14.9%]). Analyses by select baseline characteristics showed consistently low recurrent CDI rates in patients younger than 65 years vs 65 years or older (5 of 126 [4.0%; 95% CI, 1.3%-9.0%] vs 18 of 137 [13.1%; 95% CI, 8.0%-20.0%]) and patients enrolled based on positive PCR results (3 of 69 [4.3%; 95% CI, 0.9%-12.2%]) vs those with positive toxin EIA results (20 of 192 [10.4%; 95% CI, 6.5%-15.6%]).

CONCLUSIONS AND RELEVANCE

In this trial, oral SER-109 was well tolerated in a patient population with recurrent CDI and prevalent comorbidities. The rate of recurrent CDI was low regardless of the number of prior recurrences, demographics, or diagnostic approach, supporting the beneficial impact of SER-109 for patients with CDI.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03183141.

Address: Section of Infectious Diseases and International Medicine, Department of Internal Medicine, Beaumont Hospital, Royal Oak, Michigan.; Department of Internal Medicine, Oakland University William Beaumont School of Medicine, Rochester, Michigan.; Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, Michigan.; Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota.; Division of Digestive Disease, Yale University School of Medicine, New Haven, Connecticut.; Physicians Alliance of Connecticut-Gastroenterology Center, Hamden, Connecticut.; Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.; Department of Medicine, Warren Alpert Medical School of Brown University, Providence, Rhode Island.; Department of Gastroenterology, Palo Alto Medical Foundation, Sutter Health, Mountain View, California.; Massachusetts General Hospital, Boston.; Seres Therapeutics, Cambridge, Massachusetts.; Vanguard Gastroenterology, New York, New York.; University of California Davis Health, Sacramento.; University at Buffalo, VA Western New York Healthcare System, Buffalo.; Gastroenterology and Hepatology, Chevy Chase Clinical Research, Chevy Chase, Maryland.; Island Medical Program, University of British Columbia and University of Victoria, British Columbia, Canada.; Cleveland Clinic, Cleveland, Ohio.; Department of Pathology and Laboratory Medicine, Division of Infectious Diseases, Emory University, Atlanta, Georgia.; Division of Infectious Diseases, Henry Ford Health, Detroit, Michigan.; Western University, London, Ontario, Canada.

DOI: 10.1001/jamanetworkopen.2022.55758