A Study to Evaluate the Efficacy, Safety and Immunogenicity of a Vaccine Designed to Protect Against Infection With Shigella Sonnei in Healthy Adults

Study Summary

The purpose of this study is to evaluate the efficacy, safety and immunogenicity of the GSK3536852A vaccine, which was designed to protect against shigellosis caused by Shigella sonnei (S. sonnei) and is using the new Generalized Modules for Membrane Antigens (GMMA) platform technology developed by GlaxoSmithKline (GSK) Vaccines Institute for Global Health (GVGH). The study vaccine could be the stepping stone for the development of a multivalent broadly protective Shigella vaccine for vaccination of impoverished communities where shigellosis is endemic. However, a standalone monovalent vaccine against S. sonnei could be used to protect travelers against diarrheal shigellosis, as the vast majority of travelers' shigellosis is caused by S. sonnei, and even to protect infants in endemic regions where shigellosis is primarily caused by S. sonnei. The GSK3536852A vaccine has been tested in two Phase I dose escalation studies in Europe to assess its safety and immunogenicity via three routes of administration: intramuscular (IM), intranasal (IN) and intradermal (ID). The results from the first study (dose escalation with IM vaccination) have shown that the vaccine has an acceptable safety profile and is well-tolerated up to a dose of 100 micrograms (µg). The results from the second study (dose escalation with ID, IN and IM vaccination) showed that GSK3536852A vaccine is well-tolerated also when administered by the ID and IN routes of vaccination. However, immunogenicity data have shown that GSK3536852A vaccine administered by the ID and IN routes is not as immunogenic as GSK3536852A vaccine administered by the IM route. Therefore, it has been decided to proceed with the clinical development program of this vaccine only using the IM vaccination route. In terms of dosage, the regimen tested in Phase I studies (three doses given one month apart) did not show any significant benefit from the third dose in terms of immunogenicity, therefore a two dose schedule was selected f

Primary Outcome

Attack rate of shigellosis expressed as percentage of subjects with at least one episode of shigellosis after challenge, and 90% confidence interval (CI) (Clopper-Pearson method). Episodes of shigellosis fulfilling primary case definition: Shedding of S. sonnei 53G accompanied by moderate or severe diarrhea OR shedding with oral temperature greater than or equal to (≥) 38.5°C. Moderate diarrhea consists of 4 to 5 loose or watery (Grade \[G\]3 to 5) stools or 400 to 800 grams of G3 to 5 stools wi

Conditions Studied

Interventions

• DRUG Placebo
• BIOLOGICAL S.sonnei vaccine
• BIOLOGICAL S. sonnei 53G challenge strain

Study Locations (1)