TB Vaccine Phase 3 Trial Launched, as WHO Makes Case for Investing in Screening and Prevention
Microscopic view of mycobacterium tuberculosis in the lungs.

A Phase 3 trial of a tuberculosis vaccine candidate has been launched in South Africa, according to the Bill & Melinda Gates Medical Research Institute (Gates MRI).

The candidate vaccine – referred to as  M72/AS01E – “could potentially become the first vaccine to help prevent pulmonary TB in adolescents and adults, the most common form of the disease, and the first new TB vaccine in over a century”, according to Gates MRI, which is sponsoring the trial along with funding support from Wellcome Trust and the Bill and Melinda Gates Foundation.

“The launch of this pivotal Phase 3 trial demonstrates our commitment to harnessing the power of medical innovation to fight diseases like TB that are particularly devastating for low- and middle-income countries,” said Dr Emilio Emini, CEO of the Gates MRI. 

“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.”

M72/AS01E was originally designed and clinically evaluated by the biopharma company GSK up to the proof-of-concept phase (Phase 2b). 

In 2020, GSK announced a partnership with the Gates MRI for its further development. GSK continues to provide technical assistance and is supplying the adjuvant component for the Phase 3 trial and will provide the adjuvant post-licensure should the trial be successful. An adjuvant is an ingredient used in some vaccines that can help create a stronger immune response. 

Up to 60 trial sites

“Reaching Phase 3 with an urgently needed TB vaccine candidate is an important moment for South Africans because it demonstrates that there is a strong local and global commitment to fight a disease that remains distressingly common in our communities,” said Dr Lee Fairlie, national principal investigator for the trial in South Africa.

“South Africa also has considerable experience with TB- and vaccine-related clinical trials and a strong track record for protecting patient safety and generating high quality data essential for regulatory approvals.”

At full capacity, the trial will include up to 20,000 participants, including people living with HIV, at up to 60 trial sites in South Africa, Zambia, Malawi, Mozambique, Kenya, Indonesia and Vietnam. 

“After dedicating over 20 years to developing this essential candidate vaccine, we at GSK are delighted that the Phase 3 trial is underway,” said Deborah Waterhouse, CEO of ViiV Healthcare and GSK’s president of global health.

“Developing and ensuring access to global health products is complex but our collaboration with the Gates MRI, Wellcome and the Gates Foundation exemplifies the transformative power of leveraging diverse partners’ expertise to change the trajectory of challenging diseases, like TB, which place a huge burden on communities around the world.”

WHO investment case for screening and prevention

Every dollar invested in TB screening and prevention will translate to $39 in economic and health gain, according to the World Health Organization (WHO) investment case released this week.

The analysis is based on the results of a modelling study developed with the governments of four countries – Brazil, Georgia, Kenya and South Africa. 

“The investment case outlines the health and economic rationale for investing in evidence-based, WHO-recommended interventions on TB screening and prevention that can contribute to advancing universal health coverage,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “Today, we have the knowledge, tools and political commitment that can end this millennia-old disease that remains one of the world’s top infectious killers,” he said. 

TB causes 1.3 million deaths each year and affects millions more, mostly in low-and middle-income countries. Global efforts to combat TB have saved an estimated 75 million lives since the year 2000, according to the WHO.

This year, World Tuberculosis Day on 24 March is being commemorated under the theme ‘Yes! We can end TB!’ conveying a message of hope.

But WHO experts conceded that access to TB drugs remained constrained due to limited investments, speaking at a press conference on Monday. 

Screening and preventive treatment cuts costs

Implementing TB screening along with preventive treatment can substantially reduce TB incidence and mortality, according to the investment report. It argues that these crucial public health investments are essential for addressing the needs of vulnerable populations.

In 2022, WHO reported a significant worldwide recovery in the scale-up of access to TB diagnosis and treatment services, with the highest figure recorded since WHO began global TB monitoring in 1995.

But so far the scale-up of access to TB preventive treatment has been slow. It is also vital to offer TB preventive treatment to those with HIV, household contacts of TB patients, and other high-risk groups.

The global number of people living with HIV and household contacts of people with TB who were provided with TB preventive treatment increased to 3.8 million in 2022 or about 60% of those targeted that year in line with the commitments made at the UN High-Level Meeting of 2018.

Dr Saskia Den Boon, Technical Officer at the WHO’s Global TB Programme.

“Strategies to provide TB preventive treatments are often linked to screening to find and treat people with TB earlier in the course of their disease. And this helped to reduce transmission and improve outcomes. TB screening is a key intervention to find and treat the millions of people not accessing care for TB disease,” Dr Saskia Den Boon, Technical Officer at the WHO’s Global TB Programme.

Lack of vaccines

Vaccines are normally an effective preventive strategy but currently the only available vaccine for TB is the BCG vaccine that is over a century old.

“That’s the BCG, which was only for kids and it is not really effective to provide adults protection against TB,” said Ashna Ashesh, a TB survivor and public health professional and representative of WHO Civil Society Taskforce on TB.

“We’ve seen how fast we can work when we put our money where our mouth is with COVID. We had a vaccine within a year. But that wasn’t because we started from scratch in that one year. We invested in decades of mRNA research that then allowed us to quickly develop the COVID vaccine.”

Dr Tereza Kasaeva, Director of the Global Tuberculosis Programme at the WHO

“It’s absolutely unacceptable that in 21st century with a lot of innovations, we still don’t have new effective TB vaccine,” said Dr Tereza Kasaeva, WHO’s TB director. “This area of the development of new vaccines, it’s very expensive, highly risky area,” she added. 

Kasaeva said that there are more than 16 candidates in the pipeline and newer vaccines could come in the market in the next five years but added that investments are needed.

“And if you look, first of all at the situation with funding of TB research, [it is] less than o$1 billion annually. Overall investments in TB research are absolutely not sufficient,” she said. 

Multidrug-resistant TB 

Multidrug-resistant TB (MDR-TB) remains a public health crisis. While an estimated 410,000 people developed multidrug-resistant or rifampicin-resistant TB in 2022, only about two in five people accessed treatment.

The global targets approved at the 2023 UN High-Level Meeting on TB include: reaching 90% of people in need with TB prevention and care services; using a WHO-recommended rapid test as the first method of diagnosing TB; providing a health and social benefit package to all people with TB; ensuring the availability of at least one new TB vaccine that is safe and effective; and closing funding gaps for TB implementation and research by 2027.

Following the commitments made by Heads of State at the UN High-Level Meeting in 2023 to accelerate progress to end TB, this year’s focus is on tangible action, the world health body said. 

Additional reporting by Kerry Cullinan.

Image Credits: Roche .

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