The final results of a Phase 2b human trial into the efficacy of a new tuberculosis (TB) vaccine have been published, indicating safe long-term protection from the devastating disease in around half of the subjects vaccinated. The research will now move into the final phase of trials in the hopes of clinical deployment within seven to 10 years.
“TB is a disease that is preventable, treatable and curable, yet last year it killed 1.5 million people, more than HIV/AIDS,” explains Paula Fujiwara, scientific director of the International Union Against Tuberculosis and Lung Disease. “We cannot end the TB emergency unless we dramatically scale up prevention in those parts of the world where we are treating it. The cost of inaction is more unnecessary suffering and death.”
The current TB vaccine has been in use for almost a century, and it is one of the most widely used vaccines in the world. Its big limitation, however, is that its efficacy in adults is minimal, especially if one has already contracted a dormant form of the disease.
The trials for this new TB vaccine have been taking place in sub-Saharan Africa for several years and the long-term Phase 2b results have finally been published. The randomized, double-blind, placebo-controlled study followed over 3,500 subjects for three years. The long-term follow-up data found 26 subjects in the placebo group developed active TB compared to only 13 in the vaccine group. This suggests the vaccine is around 50 percent effective in preventing the onset of the disease.
These results don’t suggest the vaccine provides complete protection for everyone, but even at around 50 percent efficacy the treatment has the potential to save millions of lives. And importantly, the vaccine is the first to show beneficial effects in adults that already are infected with a dormant form of the disease.
“These final results show that [the vaccine] could be an important tool in the fight against pulmonary tuberculosis,” says Mark Feinberg, CEO of IAVI – a nonprofit research organization working on the development of the vaccine. “While additional trials need to be conducted to confirm these findings in other populations, we have never before seen a vaccine that provides protection in adults who are already infected with the bacteria that cause tuberculosis.”
Speaking to BBC News, TB expert David Lewinsohn suggests this vaccine could be a “game-changer” and the newly published results indicate promising human safety and efficacy data. Moving forward, larger trials to verify these results are necessary, meaning it could be up to 10 years before the vaccine is approved and rolled out.
"It is likely that the vaccine will need to be tested in additional populations, and possibly bigger trials before it will be licensed,” says Lewinsohn. “Assuming the data holds up in the remaining trials, which seems likely, this vaccine has the potential to revolutionize TB treatment."
The new data was published in The New England Journal of Medicine.
Sources: GSK, University of Minnesota