First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children

Selidji Todagbe Agnandji, Bertrand Lell, Solange Solmeheim Soulanoudjingar, José Francisco Fernandes, Béatrice Peggy Abossolo, Cornelia Conzelmann, Barbara Gaelle Nfono Ondo Methogo, Yannick Doucka, Arnaud Flamen, Benjamin Mordmüller, Saadou Issifou, Peter Gottfried Kremsner, Jahit Sacarlal, Pedro Aide, Miguel Lanaspa, John J Aponte, Arlindo Nhamuave, Diana Quelhas, Quique Bassat, Sofia MandjateEusébio Macete, Pedro Alonso, Salim Abdulla, Nahya Salim, Omar Juma, Mwanajaa Shomari, Kafuruki Shubis, Francisca Machera, Ali Said Hamad, Rose Minja, Ali Mtoro, Alma Sykes, Saumu Ahmed, Alwisa Martin Urassa, Ali Mohammed Ali, Grace Mwangoka, Marcel Tanner, Halidou Tinto, Umberto D'Alessandro, Hermann Sorgho, Innocent Valea, Marc Christian Tahita, William Kaboré, Sayouba Ouédraogo, Yara Sandrine, Robert Tinga Guiguemdé, Jean Bosco Ouédraogo, Mary J Hamel, John Lusingu, Thor Theander, RTS,S Clinical Trials Partnership

598 Citations (Scopus)

Abstract

BACKGROUND: An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries. METHODS: From March 2009 through January 2011, we enrolled 15,460 children in two age categories - 6 to 12 weeks of age and 5 to 17 months of age - for vaccination with either RTS,S/AS01 or a non-malaria comparator vaccine. The primary end point of the analysis was vaccine efficacy against clinical malaria during the 12 months after vaccination in the first 6000 children 5 to 17 months of age at enrollment who received all three doses of vaccine according to protocol. After 250 children had an episode of severe malaria, we evaluated vaccine efficacy against severe malaria in both age categories. RESULTS:In the 14 months after the first dose of vaccine, the incidence of first episodes of clinical malaria in the first 6000 children in the older age category was 0.32 episodes per person-year in the RTS,S/AS01 group and 0.55 episodes per person-year in the control group, for an efficacy of 50.4% (95% confidence interval [CI], 45.8 to 54.6) in the intention-to-treat population and 55.8% (97.5% CI, 50.6 to 60.4) in the per-protocol population. Vaccine efficacy against severe malaria was 45.1% (95% CI, 23.8 to 60.5) in the intention-to-treat population and 47.3% (95% CI, 22.4 to 64.2) in the per-protocol population. Vaccine efficacy against severe malaria in the combined age categories was 34.8% (95% CI, 16.2 to 49.2) in the per-protocol population during an average follow-up of 11 months. Serious adverse events occurred with a similar frequency in the two study groups. Among children in the older age category, the rate of generalized convulsive seizures after RTS,S/AS01 vaccination was 1.04 per 1000 doses (95% CI, 0.62 to 1.64). CONCLUSIONS:The RTS,S/AS01 vaccine provided protection against both clinical and severe malaria in African children. (Funded by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative; RTS,S ClinicalTrials.gov number, NCT00866619.)

Original languageEnglish
JournalNew England Journal of Medicine
Volume365
Issue number20
Pages (from-to)1863-75
Number of pages13
ISSN0028-4793
DOIs
Publication statusPublished - 17 Nov 2011

Keywords

  • Africa
  • Age Factors
  • Double-Blind Method
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Infant
  • Intention to Treat Analysis
  • Malaria Vaccines
  • Malaria, Falciparum
  • Male
  • Meningitis
  • Parasite Load
  • Plasmodium falciparum
  • Seizures
  • Treatment Outcome

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