International non-profit research company IAVI has dosed the first patients in its Phase IIb trial of tuberculosis (TB) vaccine, which, if approved, could be the second to be cleared in more than 100 years.

Alongside Spanish biopharmaceutical company Biofabri, the randomised placebo-controlled IMAGINE trial examining MTBVAC (NCT06272812) will recruit approximately 4,300 adolescent and adult patients with latent TB infection, shown by a positive interferon gamma release assay (IGRA) test, across 15 sites in South Africa, Kenya, and Tanzania.

The current standard of care for TB has remained unchanged since the invention of the first vaccine, Bacillus Calmette-Guérin (BCG), in 1921. This vaccine is thought to last approximately 20 years and doesn’t offer complete protection into adolescence and adulthood. This vaccine was originally derived from the bovine version of the disease, mycobacterium bovis. In contrast, MTBVAC is a live-attenuated TB vaccine candidate derived from mycobacterium tuberculosis.

A previous Phase II study (NCT03536117) examined the vaccine in newborns, with Biofabri now conducting a Phase III trial of the vaccine in neonates in South Africa, Madagascar, and Senegal.

A separate study, published in Nature, found MTBVAC in adult rhesus macaques showed a significant improvement following aerosol exposure to M. tuberculosis compared to a single BCG vaccine.

Lewis Schrager, head of IAVI’s TB vaccine development group, said: “The IMAGINE trial is an important new effort to develop a vaccine capable of combatting the world’s deadliest disease. Because MTBVAC is a single-shot vaccine we are hopeful that, if proven effective, MTBVAC could prevent millions of cases of TB disease, particularly in persons living in some of the world’s most difficult-to-reach locations.”

The vaccine was initially designed by researchers at the University of Zaragoza alongside the Institut Pasteur and is now developed and licensed by Biofabri. Funding for the trials was provided by Open Philanthropy, the Bill and Melinda Gates Foundation, and the German Federal Ministry of Education and Research.

Research by the World Health Organization (WHO) estimates that 1.25 million people died as a result of TB in 2023 alone. It is currently considered to be one of the world’s leading causes of death from a single infectious agent and a driver of anti-microbial resistance. Under the right circumstances, TB can become zoonotic, meaning it can spread between species.

Keertan Dheda, principal investigator for the trial, said: “An effective vaccine is urgently needed for TB, historically the biggest killer of mankind, which results in 11 million newly diseased individuals every year.

“Besides the millions of resultant deaths, TB is also associated with substantial reductions in the gross domestic product of low- and middle-income countries, given that economically active young people are often affected by the disease.”

Experts have raised concerns about TB research as some funding comes from the US Agency for International Development (USAID), which has recently been stopped. Experts have said that sponsors, agencies or foundations may have to fill funding gaps to ensure vital research continues.

Elsewhere in the treatment of TB, Medical AI company Lunit’s chest X-ray analysis software INSIGHT CXR has demonstrated superior performance in TB detection.