Key TB vaccine candidate fails to offer added benefit in trial

A highly anticipated trial of a new tuberculosis vaccine demonstrated no added benefit over the current vaccine when it came to protecting babies, researchers said on Monday.

The trial of the MVA85A vaccine, the first new TB vaccine in 90 years, was developed by researchers from the University of Oxford with support from several other organizations. It is the most advanced of more than a dozen TB vaccines currently in clinical trials. Scientists are examining the results to determine why the trial might have failed, Reuters reports.

"Obviously, we all would have liked to see greater protection," Ann Ginsberg, a doctor with the non-profit biotech Aeras, said, according to Reuters.

The current TB vaccine, known as the Bacille Calmette-Guerin vaccine, was developed in 1921. The protection from the vaccine wears off in just a few years and does nothing to protect against lung-invasive pulmonary TB.

The study tested the new vaccine with half of 3,000 babies who already received the BCG vaccine in South Africa. Two years later, 32 babies in the MVA85A group got TB compared with 39 in the placebo group. The improvement was considered statistically insignificant and was much lower than had been seen in previous studies with adults.

"This is the first efficacy trial of a new TB vaccine since Bacille Calmette-Guérin, a significant step in itself, and there is much that we and others can learn from the study and the data it produced," Helen McShane, the developer of the vaccine from the University of Oxford, said, according to Reuters.

Ginsberg said that the world should not get discouraged by the trial failure because TB is too urgent a problem and the current tools are too inadequate to fix the global TB epidemic.

"The one thing that could change the game on the TB epidemic is to have safe, affordable and effective vaccines," Ginsberg said, according to Reuters. "We absolutely cannot afford to slow down at all."

The University of Oxford developed MVA85A with help from Aeras, the Wellcome Trust, the European Commission and the Oxford-Emergent Tuberculosis Consortium, Reuters reports.