Dataset Information

236. Treatment of Recurrent Clostridioides difficile Infection With RBX2660 in Patients ≥ 65 Years Old With Underlying Comorbidities

ABSTRACT: Abstract

Background

Disruptions to gut microbiota composition can result in dysbiosis and subsequent intestinal colonization by opportunistic pathogens such as Clostridioides difficile.1,2 The incidence of Clostridioides difficile infection (CDI) in persons ≥ 65 years old is greater than in those < 65 years old,3 with 1 in 11 CDI patients ≥ 65 years old dying within 1 month of diagnosis.4 We report the efficacy and safety of RBX2660, a microbiota-based live biotherapeutic, in patients with recurrent CDI (rCDI) who were ≥ 65 years old with comorbidities. This is a subgroup analysis of the PUNCH CD3 trial (NCT03244644), a prospective, multicenter, randomized, double-blind, placebo-controlled phase 3 trial.

Methods

Participants enrolled in PUNCH CD3 were ≥ 18 years old with documented rCDI who completed standard-of-care antibiotic therapy prior to treatment with RBX2660 or placebo. Treatment success was defined as remaining recurrence-free 8 weeks after intervention. In this subgroup analysis, we assessed outcomes of participants ≥ 65 years old with underlying cardiac disorders, chronic kidney disease (CKD), and gastrointestinal (GI) disorders. The treatment-emergent adverse events (TEAEs) were summarized for the double-blind treatment period within 8 weeks and censored if a patient received open-label RBX2660 after CDI recurrence.

Results

In the modified intent-to-treat population, 119 of 262 participants (45%) were ≥ 65 years old. Of these 119 participants, 42% had a cardiac disorder, 19% had CKD, and 61% had a GI disorder; the respective RBX2660 treatment success rates were 69%, 68%, and 67% (Figure 1). In the total safety population, the overall incidence of TEAEs was 52% with RBX2660 treatment compared to 44% with placebo treatment; mild events accounted for most of the difference (40% vs 30%) (Table 1). The overall incidence of TEAEs was 51% in RBX2660-treated participants ≥ 65 years old and 61%, 68%, and 51% in those participants with a cardiac disorder, CKD, or GI disorder, respectively. Most TEAEs were mild or moderate in severity and related to a pre-existing condition.

Conclusion

RBX2660 is safe and efficacious across a range of medically complex patients and consistently reduced rCDI in adults ≥ 65 years old, regardless of baseline comorbidities.

Disclosures

Glenn S. Tillotson, PhD, Ferring Pharmaceuticals: Advisor/Consultant|Paratek Pharmaceuticals: Grant/Research Support|Spero Pharmaceuticals: Advisor/Consultant|Taro Pharmaceuticals: Advisor/Consultant Paul Feuerstadt, MD, FACG, AGAF, Ferring/Rebiotix Pharmaceuticals: Advisor/Consultant|Ferring/Rebiotix Pharmaceuticals: Grant/Research Support|Merck and Co: Advisor/Consultant|SERES Therapeutics: Advisor/Consultant|SERES Therapeutics: Grant/Research Support|Takeda Pharmaceuticals: Advisor/Consultant Stuart Johnson, M.D., Ferring Pharmaceuticals: Membership on Ferring Publication Steering Committee|Ferring Pharmaceuticals: Employee|Summit Plc: Advisor/Consultant Adam Harvey, PhD, Ferring Pharmaceuticals: Employment.

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PROVIDER: S-EPMC9751783 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature

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Project description:IntroductionEffective 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.MethodsThe 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.ResultsFor 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.ConclusionWhile 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 registrationClinicalTrials.gov: NCT02299570.

Project description:BackgroundRecurrent Clostridioides difficile infection, associated with dysbiosis of gut microbiota, has substantial disease burden in the USA. RBX2660 is a live biotherapeutic product consisting of a broad consortium of microbes prepared from human stool that is under investigation for the reduction of recurrent C. difficile infection.MethodsA randomized, double-blind, placebo-controlled, phase III study, with a Bayesian primary analysis integrating data from a previous phase IIb study, was conducted. Adults who had one or more C. difficile infection recurrences with a positive stool assay for C. difficile and who were previously treated with standard-of-care antibiotics were randomly assigned 2:1 to receive a subsequent blinded, single-dose enema of RBX2660 or placebo. The primary endpoint was treatment success, defined as the absence of C. difficile infection diarrhea within 8 weeks of study treatment.ResultsOf the 320 patients screened, 289 were randomly assigned and 267 received blinded treatment (n = 180, RBX2660; n = 87, placebo). Original model estimates of treatment success were 70.4% versus 58.1% with RBX2660 and placebo, respectively. However, after aligning the data to improve the exchangeability and interpretability of the Bayesian analysis, the model-estimated treatment success rate was 70.6% with RBX2660 versus 57.5% with placebo, with an estimated treatment effect of 13.1% and a posterior probability of superiority of 0.991. More than 90% of the participants who achieved treatment success at 8 weeks had sustained response through 6 months in both the RBX2660 and the placebo groups. Overall, RBX2660 was well tolerated, with manageable adverse events. The incidence of treatment-emergent adverse events was higher in RBX2660 recipients compared with placebo and was mostly driven by a higher incidence of mild gastrointestinal events.ConclusionsRBX2660 is a safe and effective treatment to reduce recurrent C. difficile infection following standard-of-care antibiotics with a sustained response through 6 months.Clinical trial registrationNCT03244644; 9 August, 2017.