Bharat Biotech partners with GSK to further develop Shigella vaccine candidate altSonflex1-2-3

Hyderabad: Bharat Biotech International Limited (BBIL) on Thursday announced that it has partnered with GSK plc for the ongoing development and potential use of the Shigella vaccine candidate, altSonflex1-2-3.

The company said that the agreement marked a critical step in the advancement of this promising vaccine, targeting Shigellosis—a severe form of bacterial diarrhoea that disproportionately affects children under five in low- and middle-income countries.

In a public note, it said the collaboration reflects Bharat Biotech’s continued commitment to global public health and equitable vaccine access.

Clinical tests

The in-licensed candidate, altSonflex1-2-3, has already shown encouraging results in early-stage clinical trials.

A Phase 1 study conducted in Europe demonstrated a favourable safety profile and strong immune response. Subsequent Phase 2 trials in Africa, including vaccination of 9-month-old infants—the primary target population—reported no safety concerns. Interim results from 2024 confirmed that the candidate met its pre-set immunogenicity goals.

About Shigella

Shigellosis is an acute human inflammatory disease of the large intestine caused by Gram-negative Shigella. It is characterised by watery diarrhoea, fever, abdominal cramps and pain, and bloody and mucus-filled stools. Humans are the only natural hosts for Shigella.

Shigella is a major contributor to child morbidity and mortality, and the emergence of drug-resistant strains underscores the urgent need for a preventive vaccine. By helping reduce illness and antibiotic use, this vaccine has the potential to play a critical role in combating antimicrobial resistance (AMR).

Shigella is a facultatively anaerobic, non-motile Gram-negative rod from the family Enterobacteriaceae. There are four different Shigella species. The prevalence of these serotypes varies by country's economic status, between geographical regions and changes over time, even within one region, which has long presented a major challenge for vaccine development.

altSonflex1-2-3 vaccine candidate

The altSonflex1-2-3 vaccine candidate, developed by GSK and now advancing through a strategic collaboration with Bharat Biotech, represents one of the most advanced Shigella vaccine candidates globally.

With no licensed Shigella vaccine currently available and rising antimicrobial resistance, this candidate stands out for its broad serotype coverage, innovative Generalised Modules for Membrane Antigens (GMMA)-based platform, and robust early clinical results. It has already demonstrated a strong safety and immunogenicity profile in both European and African trials, including in the primary target population of 9-month-old infants. Now entering Phase 3 trials under Bharat Biotech’s leadership, altSonflex1-2-3 is poised to become the first scalable, affordable and globally accessible vaccine to combat this urgent public health threat.

GMMA technology

GMMA technology is an innovative platform that uses bacterial outer membranes to deliver the O Antigen to the immune system. This novel approach allows for high-yield production with a simple and cost-effective manufacturing process, offering a pathway to create affordable vaccines for underserved populations.

Dr. Krishna Ella, executive chairman, Bharat Biotech, said, “As the market leader in vaccines for diarrhoeal infections, including rotavirus, typhoid, polio, non-typhoidal salmonella, cholera, and paratyphi, Bharat Biotech is proud to partner with GSK to develop a next-generation Shigella vaccine candidate, for a severe form of bacterial diarrhoea affecting millions of children under five. With no approved vaccine currently available and antimicrobial resistance on the rise, there is an urgent need for scalable, science-backed solutions focused on low and middle-income countries. This collaboration combines our strengths in innovation, manufacturing, and global health commitment. The use of GMMA technology reflects our mission to deliver accessible vaccines that protect and improve lives worldwide.”

Phase 3 clinical trials by Bharat Biotech

As part of this agreement, Bharat Biotech will lead the further development of altSonflex1-2-3, including Phase 3 clinical trials, regulatory advancement, and large-scale manufacturing. GSK will continue to support the programme by assisting with clinical trial design, securing external funding, and contributing to the Access and Delivery Plans and commercialisation strategy. GSK has an established relationship with BBIL, after signing a product transfer agreement for the world’s first malaria vaccine, RTS, to the Indian Biotech company in 2021.