GSK tuberculosis vaccine maintains efficacy out to 3 years

GlaxoSmithKline GSK House in Brentford, UK
Longer and larger studies of the GSK tuberculosis vaccine are needed to confirm the effect. (GlaxoSmithKline)

GlaxoSmithKline has shared updated data from a phase 2b trial of its tuberculosis vaccine candidate M72/AS01E. Three years after vaccination, protection against active pulmonary tuberculosis disease remained up around 50%, suggesting the candidate provides lasting immunity against the bacterium.

GSK shared two-year results from the 3,575-subject trial a little more than a year ago, revealing the vaccine protected 54% of people from active tuberculosis. Now, GSK has shared three-year data.

The updated revealed the protection rate fell slightly over the final year of the clinical trial, slipping from 54% to 49.7%. Even after the slight slide, the level of protection is high enough to suggest the vaccine could be a useful tool in the fight against tuberculosis.

In the trial, 26 subjects in the control group developed active pulmonary tuberculosis disease. In the vaccine arm, 13 people developed the disease. That numerically small difference could have a major impact if scaled across the population at risk of tuberculosis, which was responsible for 1.5 million deaths last year. The figure makes tuberculosis the most deadly infectious disease globally.

The World Health Organization (WHO) wants to slash the number of tuberculosis cases and deaths, setting itself the target of reducing the number of people killed by the disease by 95% by 2035. However, the WHO will need to wait a while longer before M72/AS01E can play a big role in that push. 

“These results need confirmation in larger and longer studies conducted in a broader range of populations, including persons who have negative results on interferon-γ release assay, who are of various ethnic backgrounds, who live in various geographic locations and who are of various age groups,” the authors of a New England Journal of Medicine paper describing the results wrote.