Photo credit: PATH Malaria Vaccine Initiative/David Poland
31 Jan 2011

The large-scale Phase 3 efficacy trial for the RTS,S malaria vaccine candidate successfully reached its target enrollment on January 31, 2011. 

The 6–12 week-old infant group reached full enrollment with 6,537 confirmed participants, which together with the 8,923 enrolled in the 5–17 month-old age category totals 15,460 for the study. Vaccination of the children participating in the study will continue until the end of 2012, with additional follow-up through to the end of 2013.

This Phase 3 efficacy trial began in May 2009, with the first child vaccinated in Bagamoyo, Tanzania, one of 11 trial sites in seven sub-Saharan African countries participating in the study. Initial results from the study are expected in late 2011 for the 5–17 month group and late 2012 for the 6–12 week group. The final analysis is expected in late 2014.

RTS,S is the most clinically advanced malaria vaccine candidate in the world. In clinical trials, it was the first to demonstrate that it can provide substantial, although not complete, protection for young children and infants in malaria-endemic areas against infection and clinical disease caused by Plasmodium falciparum, the most deadly species of the malaria parasite.

In January 2001, GlaxoSmithKline (GSK) and the PATH Malaria Vaccine Initiative (MVI) – with grant monies from the Bill & Melinda Gates Foundation to MVI – entered into a public-private partnership to develop the vaccine for use in infants and young children in sub-Saharan Africa. Beginning in 2001, Phase 2 trials were conducted in partnership with African health research institutions, and today RTS,S is the first malaria vaccine candidate to ever reach large-scale Phase 3 clinical testing, one of the final stages of development before regulatory file submission.