Emergent's TB vaccine misses in Phase IIb trial

Emergent BioSolutions Inc. (NYSE:EBS) said a single intradermal dose of MVA85A missed the primary efficacy endpoint of reducing the incidence of tuberculosis (TB) infection vs. placebo at a median follow-up of 24.6 months in a Phase IIb trial to prevent TB. 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%. The double-blind, South African trial enrolled 2,797 infants four-six months of age without HIV infection who were vaccinated with Bacille Calmette-Guerin (BCG) at birth. Data were published in The Lancet.

BCG vaccines are used to vaccinate against TB infection, but they do not prevent pulmonary TB. MVA85A is a recombinant modified Vaccinia Ankara (rMVA) virus expressing Mycobacterium tuberculosis antigen 85A that is designed to "boost" immune responses that have been primed by a BCG vaccine to illicit a stronger immune response against TB. ...