Gates, Wellcome-backed TB vaccine starts phase 3 trial

tuberculosis vaccine

A huge and much-anticipated phase 3 trial of a new tuberculosis vaccine has kicked off in South Africa, raising hopes of a better way to tackle a disease that – despite being treatable – still kills well over a million people every year.

Patients have started to be injected with the M72/AS01E vaccine or a placebo at a clinic in Johannesburg, and the aim is eventually to recruit 20,000 patients at 60 sites in seven countries in Africa and Southeast Asia into the trial, which is sponsored to the tune of $550 million by the Gates Foundation and Wellcome, and supported by GSK.

The M72 vaccine was originally developed by GSK, which licensed it to the Bill & Melinda Gates Medical Research Institute (Gates MRI) in 2020. If effective, it could potentially become the first new vaccine for preventing pulmonary TB, an active form of the disease, in more than 100 years. In a phase 2 trial published in 2019, GSK reported that the vaccine had a protective efficacy of 50%.

The current live attenuated BCG vaccine has been in use since 1921 and, while it is effective in preventing severe TB disease in infants and young children, it provides limited protection against pulmonary TB in adolescents and adults.

Antibiotic treatment, meanwhile, can be effective, but resistance is a problem in some areas. For example, last year researchers found a high prevalence of multidrug-resistant (MDR) TB in Mozambique, which has one of the highest incidences of the disease in Africa.

Rates of TB were in decline for years, but started to creep up again during the COVID-19 pandemic, and the development of an improved TB vaccine is a key element in the United Nations’ target of ending the TB epidemic by 2035.

An estimated 10.6 million people contracted TB in 2021 and 1.3 million people died, the second year in a row that showed an increase on those metrics.

“Clinical study of the vaccine will still require years, but our incredible partners in South Africa and elsewhere who have come together for the phase 3 study share our hope in the vaccine’s potential,” said Emilio Emini, chief executive of Gates MRI.

The trial will compare M72 to placebo in South Africa, Zambia, Malawi, Mozambique, Kenya, Indonesia, and Vietnam, and will also include people living with HIV, recognising that untreated latent TB infection is more likely to advance to TB disease in co-infected patients.

According to the World Health Organization (WHO), a vaccine for adolescents and adults with 50% efficacy could save up to 8.5 million lives over a 25-year period, assuming protection lasts for at least five years. It would also prevent up to 76 million new TB cases, avoid the need for 42 million antibiotic courses, and prevent $41.5 billion in ‘catastrophic’ household costs.

TB is both a health problem and a socioeconomic problem, according to Alemnew Dagnew, who has worked as a physician in Ethiopia and now heads the M72 programme at Gates MRI.

“I saw first-hand what pulmonary TB does to communities,” he said, adding that it primarily affects people during their prime working years, leaving families without income and children without parents.

“A vaccine that could help prevent that from happening would be transformative,” said Dagnew.

Photo by Umanoide on Unsplash