Tuberculosis MVA85A vaccine trial shows lack of efficacy in infants
1 April 2013. Related: TB coinfection.
Richard Jefferys, TAG
On 4 Feburary 2013, results from the phase IIb trial of the MVA85A vaccine in 2,797 infants in South Africa (given as a booster following BCG immunisation) were published in the Lancet. [1]
The vaccine proved safe but, disappointingly, failed to show signifcant efficacy. However, as the researchers note, this was the first infant efficacy trial of a new TB vaccine since BCG was last assessed as part of the Chingleput trial in 1968; as such, it is a major milestone for the field, and analyses of the results, including assessments of the immune responses induced by the vaccine, will make a vital contribution to advancing the development of new vaccine candidates.
Results from trials in adults are pending, and it remains uncertain if the lack of efficacy in infants will be mirrored in the adult setting.
MVA85A is a recombinant attenuated version of the vaccinia virus (cowpox) combined with TB antigen 85A. It was developed at Oxford University and is being evaluated as a booster of preexisting immune responses to antigen 85A, which are present in most people either as a result of BCG vaccination or natural exposure to TB.
Reference:
Tameris MD et al. Safety and efficacy of MVA85A, a new tuberculosis vaccine, in infants previously vaccinated with BCG: a randomised, placebo-controlled phase 2b trial. The Lancet, early online publication. 4 February 2013. doi:10.1016/S0140-6736(13)60177-4.
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2813%2960177-4/abstract
Lancet commentary:
http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)60137-3/fulltext
Press release from trial sponsors:
http://www.aeras.org/newscenter/downloads/news/aeras_news_1344.pdf (PDF)
i-Base/TAG annual TB pipeline report: