Results From a Randomized, Placebo-Controlled Clinical Trial of a RBX2660-A Microbiota-Based Drug for the Prevention of Recurrent Clostridium difficile Infection.

Background: Despite advancements, recurrent Clostridium difficile infections (CDI) remain an urgent public health threat with insufficient response rates to currently approved antibiotic therapies. Microbiota-based treatments appear effective, but rigorous clinical trials are required to optimize dosing strategies and substantiate long-term safety. Methods: This randomized, double-blind, placebo-controlled phase 2B trial enrolled adults with 2 or more CDI recurrences to receive: 2 doses of RBX2660, a standardized microbiota-based drug (group A); 2doses of placebo (group B); or 1 dose of RBX2660 followed by 1 dose of placebo (group C). Efficacy was defined as prevention of recurrent CDI for 8 weeks following treatment. Participants who had a recurrence within 8 weeks were eligible to receive up to 2 open-label RBX2660 doses. The primary endpoint was efficacy for group A compared to group B. Secondary endpoints included the efficacy of group C compared to group B, combined efficacy in the blinded and open-label phases, and safety for 24 months. Results: The efficacy for groups A, B, and C were 61%, 45%, and 67%, respectively. The primary endpoint was not met (P = .152). One RBX2660 dose (group C) was superior to placebo (group B; P = .048), and the overall efficacy (including open-label response) for RBX2660-treated participants was 88.8%. Adverse events did not differ significantly among treatment groups. Conclusions: One, but not 2, doses of RBX2660 was superior to placebo in this randomized, placebo-controlled trial. These data provide important insights for a larger phase 3 trial and continued clinical development of RBX2660. Clinical Trials Registration: NCT02299570.

Safety and Durability of RBX2660 (Microbiota Suspension) for Recurrent Clostridium difficile Infection: Results of the PUNCH CD Study.

BACKGROUND: Managing recurrent Clostridium difficile infection (CDI) presents a significant challenge for clinicians and patients. Fecal microbiota transplantation (FMT) is a highly effective therapy for recurrent CDI, yet availability of a standardized, safe, and effective product has been lacking. Our aim in this study was to assess the safety and effectiveness of RBX2660 (microbiota suspension), a commercially prepared FMT drug manufactured using standardized processes and available in a ready-to-use format. METHODS: Patients with at least 2 recurrent CDI episodes or at least 2 severe episodes resulting in hospitalization were enrolled in a prospective, multicenter open-label study of RBX2660 administered via enema. Intensive surveillance for adverse events (AEs) was conducted daily for 7 days following treatment and then at 30 days, 60 days, 3 months, and 6 months. The primary objective was product-related AEs. A secondary objective was CDI-associated diarrhea resolution at 8 weeks. RESULTS: Of the 40 patients enrolled at 11 centers in the United States between 15 August 2013 and 16 December 2013, 34 received at least 1 dose of RBX2660 and 31 completed 6-month follow-up. Overall efficacy was 87.1% (16 with 1 dose and 11 with 2 doses). Of 188 reported AEs, diarrhea, flatulence, abdominal pain/cramping, and constipation were most common. The frequency and severity of AEs decreased over time. Twenty serious AEs were reported in 7 patients; none were related to RBX2660 or its administration. CONCLUSIONS: Among patients with recurrent or severe CDI, administration of RBX2660 via enema appears to be safe and effective. CLINICAL TRIALS REGISTRATION: NCT01925417.

A randomized, double blind, placebo-controlled trial of an oral synbiotic (AKSB) for prevention of travelers' diarrhea.

BACKGROUND: Travelers' diarrhea (TD) is a significant problem for travelers. TD is treatable once it occurs, but few options for prevention exist. Probiotics have been studied for prevention or treatment of TD; however, very few combination probiotics have been studied. Therefore, the purpose of this study was to determine if prophylactic use of an oral synbiotic could reduce the risk of acquiring TD and reduce antibiotic use if TD occurred. METHODS: Healthy subjects traveling to an area of the world with an increased risk of TD were eligible. All subjects received pre-travel counseling and were provided antibiotics and antidiarrheals (loperamide) for use only if TD developed. The subjects were blinded and randomized to take two capsules of placebo or oral synbiotic (a combination of two probiotics and a prebiotic) called Agri-King Synbiotic (AKSB) beginning 3 days prior to departure, daily while traveling, and for 7 days after return. All subjects kept symptom and medication diaries and submitted a stool sample for pathogen carriage within 7 days of return. The study was powered to detect a 50% reduction in the incidence of TD. RESULTS: Of the 196 adults (over 18 years of age) enrolled in the study, 54.3% were female and 80.9% were younger than 60 years. The study randomized 94 people to the AKSB arm and 102 to placebo. The incidence of TD was 54.5% in the overall group with 55.3% in the AKSB arm and 53.9% in the placebo (p = 0.8864). Among the subjects who experienced diarrhea (n = 107) there was no significant difference in the proportion of subjects that took antibiotics versus those that did not take antibiotics (35% vs 29%, p = 0.68). AKSB was safe with no difference in toxicity between the two arms. CONCLUSIONS: The prophylactic oral synbiotic was safe but did not reduce the risk of developing TD among travelers, nor did it decrease the duration of TD or the use of antibiotics when TD occurred.