Fecal Microbiota, Live-jslm for the Prevention of Recurrent Clostridioides difficile Infection : Subgroup Analysis of PUNCH CD2 and PUNCH CD3

GOALS

To assess fecal microbiota, live-jslm (REBYOTA, abbreviated as RBL, formerly RBX2660) efficacy and safety in participants grouped by recurrent Clostridioides difficile infection (rCDI) risk factors and treatment-related variables.

BACKGROUND

RBL is the first microbiota-based live biotherapeutic approved by the US Food and Drug Administration for the prevention of rCDI in adults after antibiotic treatment for rCDI.

STUDY

Treatment success rates across subgroups for PUNCH CD3 (NCT03244644) were estimated using a Bayesian hierarchical model, borrowing data from PUNCH CD2 (NCT02299570). Treatment-emergent adverse events were summarized for the double-blind treatment period within 8 weeks.

RESULTS

Treatment differences between RBL and placebo at 8 weeks were similar to the total population for most subgroups. Treatment effect sizes were similar between CDI tests, higher for oral vancomycin courses >14 days versus ≤14 days and higher for antibiotic washout periods of 3 days versus ≤2 days. The largest reductions in the rate of rCDI with RBL versus placebo were observed for participants with a 3-day CDI antibiotic washout period and participants with ≥4 previous CDI episodes. Most RBL-treated participants experienced TEAEs that were mild or moderate in severity and related to preexisting conditions.

CONCLUSION

This analysis provides further evidence of RBL efficacy and safety across subgroups, including those at high risk for rCDI.

Safety of fecal microbiota, live-jslm (REBYOTA™) in individuals with recurrent Clostridioides difficile infection: data from five prospective clinical trials

Background

Microbiota-based treatments reduce the incidence of recurrent Clostridioides difficile infections (rCDIs), but prospectively collected safety data needed to broaden patient access and protect public health have been limited.

Objectives

We provide cumulative safety data from five prospective clinical trials evaluating fecal microbiota, live-jslm (RBL) - the first microbiota-based live biotherapeutic product approved by the US Food and Drug Administration - for preventing rCDI in adults.

Design

Integrated safety analysis includes three phase II trials (PUNCH CD, PUNCH CD2, PUNCH Open-Label) and two phase III trials (PUNCH CD3, PUNCH CD3-OLS) of RBL.

Methods

Trial participants were at least 18 years of age with documented rCDI who completed standard-of-care antibiotic therapy before treatment with RBL. Assigned study treatment regimen was one or two doses of RBL (or placebo) administered rectally, depending on the trial design. In four of the five trials, participants with CDI recurrence within 8 weeks after RBL or placebo administration were eligible for treatment with open-label RBL. Treatment-emergent adverse events (TEAEs) were recorded for at least 6 months following last study treatment; in PUNCH CD2 and PUNCH Open-Label trials, TEAEs and serious TEAEs were collected through 12 and 24 months, respectively.

Results

Among the five trials, 978 participants received at least one dose of RBL (assigned treatment or after recurrence) and 83 participants received placebo only. TEAEs were reported in 60.2% of Placebo Only participants and 66.4% of RBL Only participants. Only abdominal pain, nausea, and flatulence were significantly higher in the RBL Only group compared with the Placebo Only group. Most TEAEs were mild or moderate in severity and were most frequently related to preexisting conditions. There were no reported infections for which the causative pathogen was traced to RBL. Potentially life-threatening TEAEs were infrequent (3.0% of participants).

Conclusion

Across five clinical trials, RBL was well tolerated in adults with rCDI. In aggregate, these data consistently demonstrated the safety of RBL.

Final Results from a Phase 2b Randomized, Placebo-Controlled Clinical Trial of RBX2660: A Microbiota-Based Drug for the Prevention of Recurrent Clostridioides difficile Infection

INTRODUCTION

Effective treatments for recurrent Clostridioides difficile infection (rCDI) are urgently needed. RBX2660 is an investigational microbiota-based live biotherapeutic to reduce CDI recurrence following standard-of-care antibiotic treatment in individuals with rCDI. Here we report the final safety data through 24 months of follow-up as well as final efficacy data, reflecting alignment of the pre-specified statistical analysis plan definitions with the data presented.

METHODS

The PUNCH CD2 clinical trial was a prospective, multicenter, randomized, double-blinded, placebo-controlled, three-arm phase 2b study conducted to evaluate the efficacy and safety of RBX2660 for the reduction of rCDI compared to placebo. Eligible patients were at least 18 years of age and had at least three episodes of CDI and at least two rounds of standard antibiotic treatment or had at least two episodes of severe CDI resulting in hospitalization. Patients were randomized 1:1:1 to group A, two doses of RBX2660; group B, two doses of placebo; or group C, one dose of RBX2660 and one dose of placebo; all administered 7 ± 2 days apart. Treatment success was prevention of recurrence, defined as absence of diarrhea and no re-treatment for CDI any time after the first dose until 8 weeks after the second dose of the study treatment. Safety was assessed by reports of adverse events and symptoms. The final efficacy and safety are reported for data available through 24 months.

RESULTS

For the primary endpoint, treatment success at 8 weeks, 56.8% (25/45) of participants who received one dose of RBX2660 + one dose of placebo, 55.6% (25/45) of participants who received two doses of RBX2660, and 43.2% (19/44) of participants who received two doses of placebo in the final intention-to-treat (ITT) population were responders (both p = 0.2 vs placebo). In the per-protocol population, 87.5% (21/24) of participants who received one dose of RBX2660 + one dose of placebo and 58.1% (18/31) of those who received two doses of placebo had treatment success (p = 0.017; treatment difference, 29.4 [95% CI 7.6, 51.3]); 75.0% (21/28) of participants in the PP population who received two doses of RBX2660 were responders (p = 0.17 vs placebo). The safety profile of RBX2660, whether delivered as one or two doses, was similar to the placebo group.

CONCLUSION

While the phase 2b PUNCH CD2 clinical trial did not meet its pre-defined primary endpoint of treatment success at 8 weeks after two doses of RBX2660 vs two doses of placebo, clinically meaningful data were obtained to justify proceeding with the single dose regimen in the phase 3 clinical trial, PUNCH CD3, now complete. To date, the cumulative data for RBX2660 demonstrate consistent efficacy and safety outcomes for reduction of CDI recurrence in adults.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02299570.

1042. Safety of Investigational Microbiota-Based Live Biotherapeutic RBX2660 in Individuals with Recurrent Clostridioides difficile Infection: Data from Five Prospective Clinical Studies

Background

Microbiota-based treatments have shown promise to reduce recurrence, morbidity, and mortality for recurrent Clostridioides difficile infections (rCDI), but consistent and reliable safety data are needed to support regulatory approvals and broaden patient access. Here we provide cumulative safety data from 5 prospective clinical studies evaluating RBX2660—a standardized, microbiota-based investigational live biotherapeutic—for reducing rCDI.

Methods

This analysis included three Phase 2 (PUNCH CD, PUNCH CD2, PUNCH CD Open Label) and two Phase 3 trials (PUNCH CD3, PUNCH CD3-OLS ad hoc analysis). Participants were ≥18 years old with documented rCDI who completed standard-of-care oral antibiotic therapy prior to treatment with RBX2660. PUNCH CD3-OLS allowed participants with comorbidities of irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). Depending on the trial, assigned study treatment was 1 or 2 doses of RBX2660 (or placebo), administered rectally. Participants whose CDI recurred within 8 weeks were eligible for additional RBX2660 treatment. Treatment-emergent adverse events (TEAEs) were recorded for at least 6 months following last study treatment; CD2 and CD Open Label recorded TEAEs for 24 months.

Results

Among 620 participants who received at least one RBX2660 dose (assigned treatment or after recurrence), 324 (52.3%) received 1, 270 (43.5%) received 2, 14 (2.3%) received 3, and 12 (1.9%) received 4. 83 participants received blinded placebo only. A total of 1980 TEAEs were reported from 432 (69.7%) RBX2660-treated participants, compared to 174 TEAEs in 50 (60.2%) placebo-only treated participants. Most TEAEs were mild or moderate in severity, with diarrhea common in all treatment groups. No potentially life-threatening TEAEs were considered related to RBX2660. Study discontinuation due to TEAEs was minimal (< 1%) with none related to RBX2660. There were no reported infections for which the causative pathogen was traced to RBX2660.

Conclusion

Across five clinical studies with consistent investigational product, RBX2660 was well-tolerated in rCDI participants. In aggregate, this data provides compelling and consistent safety data for RBX2660.

Disclosures

Tricia Braun, PharmD, Rebiotix, a Ferring Company (Employee) Beth Guthmueller, AS, Rebiotix Inc, A Ferring Company (Employee) Adam J. Harvey, PhD, Rebiotix, A Ferring Company (Employee)