Final results from a large-scale Phase III trial of the RTS,S malaria vaccine candidate, including the impact of a booster dose, published last week in The Lancet, show that the vaccine candidate helped protect children and infants from clinical malaria for at least three years after first vaccination.
The latest results demonstrated that vaccination with RTS,S, followed by a booster dose of RTS,S administered 18 months after the primary schedule, reduced the number of cases of clinical malaria in children (aged 5-17 months at first vaccination) by 36% to the end of the study (over an average follow-up of 48 months across trial sites) and in infants (aged 6-12 weeks at first vaccination) by 26% to the end of the study (over an average follow-up of 38 months across trial sites). Efficacy decreased over time in both age groups. The efficacy of RTS,S was evaluated in the context of existing malaria control measures, such as insecticide treated bed nets, which were used by approximately 80% of the children and infants in the trial.
Eleven research centres in seven African countries, among which the CISM in Mozambique, conducted the efficacy and safety trial, in partnership with GSK and the PATH Malaria Vaccine Initiative (MVI), with grant funding from the Bill & Melinda Gates Foundation to MVI. The trial started in March 2009 and concluded in January 2014, enrolled 15,459 participants.
The European Medicines Agency (EMA) is currently reviewing the regulatory application for RTS,S through the Art. 58 procedure initiated in July 2014. A positive opinion from the EMA's Committee for Medicinal Products for Human Use, together with a potential policy recommendation from the World Health Organisation (anticipated by the end of 2015), would be the basis for licensure applications to National Regulatory Authorities in sub-Saharan African countries. If positive, these regulatory decisions would help pave the way for the introduction of RTS,S through African national immunisation programmes.