A phase 3 trial of RTS,S/AS01 malaria vaccine in African infants

N Engl J Med. 2012 Dec 13;367(24):2284-95. doi: 10.1056/NEJMoa1208394. Epub 2012 Nov 9.

Abstract

Background: The candidate malaria vaccine RTS,S/AS01 reduced episodes of both clinical and severe malaria in children 5 to 17 months of age by approximately 50% in an ongoing phase 3 trial. We studied infants 6 to 12 weeks of age recruited for the same trial.

Methods: We administered RTS,S/AS01 or a comparator vaccine to 6537 infants who were 6 to 12 weeks of age at the time of the first vaccination in conjunction with Expanded Program on Immunization (EPI) vaccines in a three-dose monthly schedule. Vaccine efficacy against the first or only episode of clinical malaria during the 12 months after vaccination, a coprimary end point, was analyzed with the use of Cox regression. Vaccine efficacy against all malaria episodes, vaccine efficacy against severe malaria, safety, and immunogenicity were also assessed.

Results: The incidence of the first or only episode of clinical malaria in the intention-to-treat population during the 14 months after the first dose of vaccine was 0.31 per person-year in the RTS,S/AS01 group and 0.40 per person-year in the control group, for a vaccine efficacy of 30.1% (95% confidence interval [CI], 23.6 to 36.1). Vaccine efficacy in the per-protocol population was 31.3% (97.5% CI, 23.6 to 38.3). Vaccine efficacy against severe malaria was 26.0% (95% CI, -7.4 to 48.6) in the intention-to-treat population and 36.6% (95% CI, 4.6 to 57.7) in the per-protocol population. Serious adverse events occurred with a similar frequency in the two study groups. One month after administration of the third dose of RTS,S/AS01, 99.7% of children were positive for anti-circumsporozoite antibodies, with a geometric mean titer of 209 EU per milliliter (95% CI, 197 to 222).

Conclusions: The RTS,S/AS01 vaccine coadministered with EPI vaccines provided modest protection against both clinical and severe malaria in young infants. (Funded by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative; RTS,S ClinicalTrials.gov number, NCT00866619.).

Publication types

  • Clinical Trial, Phase III
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Female
  • Humans
  • Immunization Schedule
  • Incidence
  • Infant
  • Intention to Treat Analysis
  • Malaria Vaccines* / adverse effects
  • Malaria Vaccines* / immunology
  • Malaria, Falciparum / epidemiology
  • Malaria, Falciparum / prevention & control*
  • Male
  • Plasmodium falciparum / immunology
  • Proportional Hazards Models
  • Treatment Outcome
  • Vaccines, Synthetic* / adverse effects
  • Vaccines, Synthetic* / immunology

Substances

  • Malaria Vaccines
  • RTS,S-AS01 vaccine
  • Vaccines, Synthetic

Associated data

  • ClinicalTrials.gov/NCT00866619