LimmaTech and Valneva: First Shigella vaccination in human challenge study

In the CHIM study S4V03 (Identifier: NCT06615375), S4V2 will be tested for safety and preliminary efficacy in approximately 120 healthy Shigella-naïve participants aged 18 to 50 years at three sites in the United States. The study, sponsored and conducted by LimmaTech, is a parallel-group, randomized, double-blind, multicenter, placebo- controlled study and will include two steps. In a first step, the vaccine dose will be confirmed and, in a second step, participants will be challenged with the Shigella sonnei strain 53G one month after injection of S4V2 or placebo, in order to assess the ability of S4V2 to protect against the Shigella infection. The infection rate of shigellosis caused by the Shigella sonnei strain 53G in the group vaccinated with S4V2 will then be compared to the  group of participants who received placebo injections.

Thomas Lingelbach, Chief Executive Officer of Valneva, commented, “Human challenge studies are unique in their ability to investigate and understand the onset and development of disease in a safe and highly controlled environment. This CHIM study forms part of our staggered and risk-mitigating development strategy for S4V2, as it should provide the first results on efficacy before potentially advancing to further CHIM and Phase 3 studies.”

Dr. Patricia Martin, Chief Operating Officer of LimmaTech, stated, “The start of this trial is a significant milestone for the S4V2 program and our combined efforts with Valneva to bring an effective vaccine against shigellosis to market. Today, we are an important step closer to LimmaTech’s vision of developing vaccines to fight against serious diseases and antimicrobial resistant pathogens.”

In addition to the CHIM study, LimmaTech will conduct a Phase 2 pediatric study in Low- and Middle-Income Countries expected to begin before the end of 2024. Valneva will assume all further development, including CMC (chemistry, manufacturing and controls) and regulatory activities, and be responsible for its commercialization worldwide, if approved.

Last month, the U.S. Food and Drug Administration (FDA) granted Fast Track designation to S4V2, recognizing its potential to address a serious condition and fill an unmet medical need.

Shigellosis is the second leading cause of fatal diarrheal disease worldwide. However, there is currently no approved Shigella vaccine and the development of Shigella vaccines has been identified as a priority by the World Health Organization (WHO).

About Shigellosis
Shigellosis is a global health threat caused by the Gram-negative Shigella bacteria. It is estimated that up to 165 million infections are due to Shigella of which 62.3 million occur in children younger than five years. Diarrheal infection is one of the major causes of morbidity and mortality in numerous countries as well as in travelers and deployed military personnel in endemic regions. There are an estimated 600,000 deaths attributed to Shigella each year and it is the second leading cause for diarrheal deaths. The standard treatment for shigellosis is oral rehydration and antibiotic therapy, however, the bacteria have acquired resistance to many antibiotics with numerous reports of outbreaks of multidrug-resistant strains, making treatment extremely difficult. Currently, no licensed Shigella vaccine is available.