A Human Challenge Study to Assess Protection of a Shigella Tetravalent Bioconjugate Vaccine
brief summary
In this challenge study, the bioconjugate candidate vaccine Shigella4V2 will be tested for its ability to induce an immune response that protects healthy adult volunteers from infection with a wild-type Shigella sonnei strain compared to participants receiving placebo.
detailed description
The tetravalent Shigella4V2 bioconjugate vaccine candidate will be tested for safety and preliminary efficacy in a Phase 2b controlled human infection model (CHIM) study at three sites in the United States. This trial will be conducted as a parallel-group, randomized, double-blind, multicenter, placebo-controlled study to evaluate the safety, immunogenicity, and efficacy of two injections of Shigella4V2 in healthy Shigella naïve participants 18-50 years of age, with the second injection administered one month before challenge with S. sonnei 53G strain. It will have two steps:
1. Step 1, a dose confirmation step, in which a first injection of Shigella4V2 (high dose or low dose, adjuvanted with Alhydrogel) will be administered alongside a placebo arm (phosphate-buffered saline) at a ratio of 2:2:1. A second injection of either Shigella4V2 low dose or placebo will be administered about 6 months after the first injection. 2. Step 2, in which participants will be randomized to the Shigella4V2 dose selected after Step 1 or to placebo at a ratio of 1:1. Participants will receive two injections, 28 days apart. One month after the second injection, they will be challenged with 1500 CFU of the virulent Shigella sonnei strain 53G.
official title
Phase 2b, Double-blind, Placebo-controlled Efficacy Challenge Study With the Shigella Tetravalent Bioconjugate Vaccine Shigella4V2