Study of a Candidate Clostridium Difficile Toxoid Vaccine in Subjects at Risk for C. Difficile Infection

Clostridium Difficile Infection Clinical Trial

Official title: Efficacy, Immunogenicity, and Safety Study of Clostridium Difficile Toxoid Vaccine in Subjects at Risk for C. Difficile Infection (Cdiffense™)

Status Terminated

Clinical Trial Summary

The aim of this study was to evaluate the efficacy of the Clostridium difficile vaccine to prevent primary symptomatic C. difficile infection (CDI) in participants at risk for CDI where there is a substantial unmet medical need.

Primary objective:

• To assess the efficacy of the C. difficile vaccine in preventing the onset of symptomatic primary CDI confirmed by polymerase chain reaction (PCR) in adult participants aged >= 50 years who are at risk for CDI and have received at least 1 injection.

Secondary Objectives:

Efficacy:

• To assess prevention of symptomatic PCR-confirmed primary CDI cases after 3 injections administered at 0, 7, and 30 days.

• To assess prevention of symptomatic PCR-confirmed primary CDI cases after completion of at least 2 injections.

Immunogenicity:

• To describe the immunogenicity to toxin A and toxin B at specific time points in a subset of participant and in participants with CDI at Day 0 and Day 60.

Safety:

• To describe the safety profile of all participants who received at least 1 injection.

Clinical Trial Description

The study was designed as an event-driven group sequential protocol with 4 interim analyses at defined information milestones and a final analysis when a specific number of clinical endpoints are reached. Analyses of trial futility (non-efficacy) were to be performed at the first 2 interim analyses, and the study was to be stopped if either of those analyses provided robust and compelling evidence that meaningful levels of vaccine efficacy (VE) would not be demonstrated.

Following completion of the first interim analysis (50 cases of confirmed CDI observed), the futility criterion was met and in accordance with IDMC recommendation, enrollment and further vaccination ceased in November 2017.

Due to the early termination of the study, some of the planned secondary efficacy endpoints could not be analyzed as all planned data were not collected.

Participants were randomized to receive either the candidate vaccine or a placebo that was to be administered in a 3-dose schedule. At the time of group assignment, 928 participants (10% of total enrollment) were randomized to an immunogenicity subset; and 1859 participants (20% of total enrollment) were randomized to a reactogenicity subset.

Safety was assessed in all participants in terms of unsolicited adverse events from Day 0 to Day 60, as well as serious adverse events (SAEs) throughout the study. Solicited adverse reactions were collected for 6 days following each injection in the reactogenicity subset. ;

Related Conditions & MeSH terms

• Clostridium Difficile Infection
• Clostridium Infections
• Communicable Diseases
• Infections

• NCT number: NCT01887912
• Study type: Interventional
• Source: Sanofi
• Status: Terminated
• Phase: Phase 3
• Start date: July 30, 2013
• Completion date: June 12, 2018