Tuberculosis vaccine: Phase IIb data

A double-blind, South African Phase IIb trial in 2,797 infants 4-6 months of age without HIV infection who were vaccinated with Bacille Calmette-Guerin (BCG) at birth showed that a single intradermal dose of MVA85A missed the primary efficacy endpoint of reducing the incidence of TB infection vs. placebo at a median follow-up of 24.6 months. Specifically, there were 32 cases (2%) of TB in infants receiving MVA85A vs. 39 cases (3%) in infants receiving placebo for a non-significant vaccine efficacy against TB of 17.3%. MVA85A also missed the secondary efficacy endpoint of reducing the incidence of M. tuberculosis infection vs. placebo (vaccine efficacy of -3.8%).

MVA85A was generally well tolerated and met the primary safety endpoint. The most frequent side effect observed was mild redness or swelling around the injection site. More infants receiving MVA85A had >=1 local adverse event vs. placebo (89% vs. 45%) but the number of infants with systemic adverse events (80% vs. 76%) and serious adverse events (18% for both) were similar between treatment groups. Data were published in The Lancet. BCG vaccines are used to vaccinate against TB infection, but they do not prevent pulmonary TB. MVA85A is designed to "boost" immune responses that have been primed by a BCG vaccine to illicit a stronger immune response against TB. ...