Efforts to end the tuberculosis pandemic may receive a significant boost as a promising vaccine candidate secures funding for its final phase of clinical trials. The Bill and Melinda Gates Foundation and Wellcome have announced their investment of approximately $550 million into Phase III trials for a tuberculosis vaccine called M72, which was originally developed by the drug company GSK. This funding comes after GSK abandoned the vaccine in 2019 due to a perceived lack of commercial potential.
If the upcoming trials prove successful and regulators approve the vaccine, M72 would mark the first new vaccine in a century to target tuberculosis, a disease that claimed the lives of 1.6 million people in 2021. Tuberculosis infected over 10 million individuals last year, with the majority of cases occurring in low- and middle-income countries. Among infectious diseases, only COVID-19 proved deadlier.
While tuberculosis is commonly treated using drug therapies, a vaccine would be particularly beneficial for infants and children, who make up a significant portion of the infected population. Proof-of-concept trials for M72 have demonstrated its potential to prevent pulmonary disease in 54 percent of TB-infected adults, surpassing the World Health Organization’s benchmark of 50 percent efficacy in adults.
Eric Rubin, a researcher at the Harvard T.H. Chan School of Public Health, describes the development of a new tuberculosis vaccine as “scientifically huge” and highlights the potential to save a substantial number of lives worldwide by halving the rate of TB.
The news of M72’s progress comes as drug-resistant strains of tuberculosis continue to multiply each year. Eradicating the disease is further complicated by the reliance on patients to seek treatment and return for months-long programs. The delay between M72’s trial phases also underscores persistent issues of inequity in treating infectious diseases.
In 2020, GSK licensed its experimental TB vaccine to the Gates Medical Research Institute after deciding against funding Phase III trials. The vaccine shares components with a shingles shot that has generated significant revenue for GSK. Immunologist Thomas Scriba, the deputy director of the South African Tuberculosis Vaccine Initiative, emphasizes the importance of ensuring that, if licensed, the TB vaccine is available to all who need it, particularly in low- and middle-income countries.
Additionally, other promising vaccine candidates to treat tuberculosis are currently in development. Afrigen, a WHO-supported hub in South Africa, is working on its own vaccine using mRNA technology similar to that of effective COVID-19 shots. The Gates Medical Research Institute is also engaged in developing other TB vaccines and therapeutics. M72 has outpaced over a dozen other candidates and will be tested in a large-scale trial of 26,000 people across Africa and Southeast Asia starting next year.
While the funding for the Phase III trials is a significant step forward, the approval process and subsequent rollout still present logistical and financial challenges. However, the potential impact of a widely available TB vaccine is substantial, with the WHO estimating that it could prevent 8.5 million deaths over the next 25 years.
Even if M72 proves to be effective and safe, it is unlikely to eradicate tuberculosis completely. Alexander Pym, the director of infectious disease at Wellcome, views the vaccine as a valuable addition to existing tools in combating the disease. The WHO’s strategy for reducing tuberculosis deaths by 90 percent by 2030 also includes new public health measures, therapeutics, and diagnostics.
In conclusion, the funding for Phase III trials of the M72 tuberculosis vaccine brings hope to efforts in ending the global tuberculosis pandemic. If successful, this vaccine could save millions of lives and contribute to significantly reducing the burden of the disease worldwide.