In Malawi, a Phase 3 trial of the M72/AS01E tuberculosis (TB) vaccine is underway, offering hope for a new tool in the fight against this deadly infectious disease. The trial, led by the Malawi Liverpool Wellcome Programme, aims to evaluate the vaccine's effectiveness in preventing TB in adults, a population largely unprotected by the current BCG vaccine.
The Global and Local Burden of TB
Globally, TB remains a significant public health threat. The World Health Organization (WHO) estimates that 10.8 million people fell ill with TB in 2023, and 1.25 million died from the disease. In Malawi, approximately 25,000 people develop TB each year, and an estimated 7,700 died from the disease in 2021. The currently available BCG vaccine, in use since 1921, is primarily administered to infants and young children, leaving a large gap in protection for adolescents and adults.
M72/AS01E Vaccine: A Promising Candidate
The M72 vaccine has shown promise in earlier trials. A 2019 Phase 2b trial demonstrated an effectiveness rate of almost 50% against progression to active pulmonary TB in adults, with a sustained M72-specific immune response observed for three years. This vaccine aims to prevent latent TB infection from developing into active TB disease.
Trial Design and Implementation
The Phase 3 trial in Malawi is being conducted at two sites: the Gateway Malawi Liverpool Wellcome Clinic in Blantyre and the University of North Carolina clinic at Kamuzu Central Hospital in Lilongwe. The trial aims to recruit participants aged 15-45, a demographic at high risk of developing TB. Malawi plans to enroll at least 692 participants, each receiving two doses of the vaccine. The study is projected to last four years, including two years for participant recruitment and two years for follow-up to assess TB development after vaccination.
Patrick Goodson, Senior Research Clinical Officer on the trial in Malawi, stated, "If the vaccine trial turns out to be a success, a lot of lives will be saved and will reduce the number of TB cases that we usually register per year globally and locally."
Potential Impact and Future Directions
Dr. Kuzani Mbendera, Head of the TB Programme in the Ministry of Health, described the TB vaccine trial as a potential "game-changer." He emphasized that a successful vaccine would complement existing TB prevention efforts, such as intensified case-finding among HIV-positive patients and TB preventive therapy.
The need for a new TB vaccine is underscored by the challenges faced by TB patients, including the economic burden of treatment and the impact on their livelihoods. The M72/AS01E vaccine represents a significant step forward in the global effort to combat TB and reduce its devastating impact on individuals and communities.
