Investigational TB Vaccine Receives Funding to Move into Phase 3 Clinical Trial

Wellcome and the Bill & Melinda Gates Foundation announced recently they were going to fund an investigational tuberculosis (TB) vaccine, M72, through a phase 3 clinical trial. Wellcome is providing up to $150 million and the Gates Foundation will fund the remainder, about $400 million.

The M72 vaccine was developed up to the proof-of-concept phase by GSK in conjunction with Aeras and IAVI. In 2020, GSK announced that it would partner with the Gates MRI for continued development and potential use of the M72 candidate vaccine in countries with high TB burden. GSK will continue to provide the adjuvant for the candidate vaccine’s further development and potential launch.

“TB remains one of the world’s deadliest infectious diseases,” Julia Gillard, chair of the Board of Governors at Wellcome, said in a statement. “The development of an affordable, accessible vaccine for adults and adolescents would be game-changing in turning the tide against TB.”

In 2021, an estimated 10.6 million people fell ill with TB and 1.6 million died—about 4300 people per day. The disease primarily affects people in low- and middle-income countries (LMIC), and those at highest risk are often living in poverty, with poor living and working conditions and undernutrition.

Up to a quarter of the world’s population is thought to have latent TB, a condition in which a person is infected with the bacterium that causes TB but does not have any symptoms and is at risk of progressing to active TB disease.

There are marked differences in how the LMIC vs other countries fare in terms of TB treatment and outcomes. “In the US and Europe, we have managed to get TB somewhat under control,” Michael W. Dunne MD, FIDSA chief medical officer, head of development, Bill & Melinda Gates Medical Research Institute, said in a previous interview with Contagion. “The burden of TB in the developed world has significantly reduced over time because we have good preventive measures, good treatment regimens, that can be monitored here. And that is the important point…it is more difficult to do that in the rest of the world.”

Dunne points out this is the crux of the issue and the ability to care for patients continuously over the many months it takes to cure a patient with TB. “How do we make it easier for low-and-middle-income countries to be able to get a handle on TB?”

The Bill & Melinda Gates Medical Research Institute has a special focus on health care issues in LMIC. The institute is a non-profit organization dedicated to the development and effective use of novel biomedical interventions addressing substantial global health concerns, for which investment incentives are limited. The institute works through collaborating partners and organizations, coordinating and driving the full spectrum of biopharmaceutical development activities, including pre-clinical development, full clinical development (from phase 1 through to and including phase 3), and global regulatory interactions.

The M72 vaccine candidate contains the M72 recombinant fusion protein, which is derived from two Mycobacterium tuberculosis antigens (Mtb32A and Mtb39A), combined with the GSK proprietary Adjuvant System AS01E.

In the phase 2b trial, M72 showed approximately 50% efficacy in reducing pulmonary TB in adults with latent TB infection—an unprecedented result in decades of TB vaccine research.

No timeline was announced yet for the launch of the phase 3 trial.