GSK Licenses Shigella Vaccine Candidate to Bharat Biotech for Continued Development

GSK has licensed its Shigella vaccine candidate, altSonflex1-2-3, to Bharat Biotech International Limited (BBIL), an Indian biotechnology firm. The agreement enables Bharat Biotech to proceed with the next phase of clinical development and potentially deliver the vaccine to low- and middle-income countries, where Shigella is a leading cause of illness and death among children under five.
Shigella, a Gram-negative bacterium, causes shigellosis—an acute infection of the large intestine. Symptoms include watery diarrhea, fever, abdominal cramps, and stools containing blood and mucus. The pathogen is recognized as a major contributor to diarrheal mortality in low-resource settings, particularly in young children. Though antibiotics are available, the emergence of antibiotic-resistant strains has
GSK created altSonflex1-2-3 to address this public health need. The candidate vaccine utilizes GMMA (Generalized Modules for Membrane Antigens) technology, which uses outer membrane vesicles from bacteria to deliver antigens. This platform has been engineered to naturally stimulate a strong immune response without adjuvants and supports low-cost, large-scale production. Research indicates that a 500-liter fermenter can produce 100 million doses of GMMA-based vaccine annually, with each dose costing approximately $1 to manufacture.
Initial clinical testing by GSK demonstrated promising outcomes. The company reported that both Phase 1 results and interim data from the Phase 2 trial met predefined immunogenicity benchmarks. Despite this progress, GSK chose to transfer responsibility for Phase 3 development to Bharat Biotech. The London-based pharmaceutical company will assist Bharat in designing the Phase 3 trial and will also help seek external funding for the project.
Thomas Breuer, Chief Global Health Officer at GSK, stated, “Bharat’s expertise in developing and supplying vaccines for infectious diseases, especially as a trusted supplier to Gavi, the Vaccine Alliance and UNICEF, positions them to further advance this important work.”

The collaboration follows a similar partnership between the two companies in 2021, when GSK licensed its malaria vaccine, RTS,S, to Bharat Biotech. That initiative received support from the Bill & Melinda Gates Foundation for clinical development.
The current licensing deal marks the second time in two years that GSK has transferred rights to a Shigella vaccine. In 2023, the company returned a different Shigella vaccine candidate to LimmaTech Biologics, which subsequently licensed it to Valneva. Valneva is now developing that candidate in parallel with Bharat Biotech’s efforts on altSonflex1-2-3.
Following the transfer of Shigella vaccine technology, GSK and Bharat Biotech aim to move forward with the final clinical phase, targeting an eventual rollout in regions where Shigella poses a significant health risk to children.