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Datoo MS, Natama MH, Somé A, Traoré O, Rouamba T, Bellamy D, Yameogo P, Valia D, Tegneri M, Ouedraogo F, Soma R, Sawadogo S, Sorgho F, Derra K, Rouamba E, Orindi B, Ramos Lopez F, Flaxman A, Cappuccini F, Kailath R, Elias S, Mukhopadhyay E, Noe A, Cairns M, Lawrie A, Roberts R, Valéa I, Sorgho H, Williams N, Glenn G, Fries L, Reimer J, Ewer KJ, Shaligram U, Hill AVS, Tinto H. Efficacy of a low-dose candidate malaria vaccine, R21 in adjuvant Matrix-M, with seasonal administration to children in Burkina Faso: a randomised controlled trial. Lancet 2021; 397:1809-1818. [PMID: 33964223 PMCID: PMC8121760 DOI: 10.1016/s0140-6736(21)00943-0] [Citation(s) in RCA: 200] [Impact Index Per Article: 66.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 01/03/2023]
Abstract
BACKGROUND Stalled progress in controlling Plasmodium falciparum malaria highlights the need for an effective and deployable vaccine. RTS,S/AS01, the most effective malaria vaccine candidate to date, demonstrated 56% efficacy over 12 months in African children. We therefore assessed a new candidate vaccine for safety and efficacy. METHODS In this double-blind, randomised, controlled, phase 2b trial, the low-dose circumsporozoite protein-based vaccine R21, with two different doses of adjuvant Matrix-M (MM), was given to children aged 5-17 months in Nanoro, Burkina Faso-a highly seasonal malaria transmission setting. Three vaccinations were administered at 4-week intervals before the malaria season, with a fourth dose 1 year later. All vaccines were administered intramuscularly into the thigh. Group 1 received 5 μg R21 plus 25 μg MM, group 2 received 5 μg R21 plus 50 μg MM, and group 3, the control group, received rabies vaccinations. Children were randomly assigned (1:1:1) to groups 1-3. An independent statistician generated a random allocation list, using block randomisation with variable block sizes, which was used to assign participants. Participants, their families, and the local study team were all masked to group allocation. Only the pharmacists preparing the vaccine were unmasked to group allocation. Vaccine safety, immunogenicity, and efficacy were evaluated over 1 year. The primary objective assessed protective efficacy of R21 plus MM (R21/MM) from 14 days after the third vaccination to 6 months. Primary analyses of vaccine efficacy were based on a modified intention-to-treat population, which included all participants who received three vaccinations, allowing for inclusion of participants who received the wrong vaccine at any timepoint. This trial is registered with ClinicalTrials.gov, NCT03896724. FINDINGS From May 7 to June 13, 2019, 498 children aged 5-17 months were screened, and 48 were excluded. 450 children were enrolled and received at least one vaccination. 150 children were allocated to group 1, 150 children were allocated to group 2, and 150 children were allocated to group 3. The final vaccination of the primary series was administered on Aug 7, 2019. R21/MM had a favourable safety profile and was well tolerated. The majority of adverse events were mild, with the most common event being fever. None of the seven serious adverse events were attributed to the vaccine. At the 6-month primary efficacy analysis, 43 (29%) of 146 participants in group 1, 38 (26%) of 146 participants in group 2, and 105 (71%) of 147 participants in group 3 developed clinical malaria. Vaccine efficacy was 74% (95% CI 63-82) in group 1 and 77% (67-84) in group 2 at 6 months. At 1 year, vaccine efficacy remained high, at 77% (67-84) in group 1. Participants vaccinated with R21/MM showed high titres of malaria-specific anti-Asn-Ala-Asn-Pro (NANP) antibodies 28 days after the third vaccination, which were almost doubled with the higher adjuvant dose. Titres waned but were boosted to levels similar to peak titres after the primary series of vaccinations after a fourth dose administered 1 year later. INTERPRETATION R21/MM appears safe and very immunogenic in African children, and shows promising high-level efficacy. FUNDING The European & Developing Countries Clinical Trials Partnership, Wellcome Trust, and National Institute for Health Research Oxford Biomedical Research Centre.
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Affiliation(s)
- Mehreen S Datoo
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Magloire H Natama
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Athanase Somé
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Ousmane Traoré
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Toussaint Rouamba
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Duncan Bellamy
- The Jenner Institute Laboratories, University of Oxford, UK
| | - Prisca Yameogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Daniel Valia
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Moubarak Tegneri
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Florence Ouedraogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Rachidatou Soma
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Seydou Sawadogo
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Faizatou Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Karim Derra
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Eli Rouamba
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | | | - Fernando Ramos Lopez
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Amy Flaxman
- The Jenner Institute Laboratories, University of Oxford, UK
| | | | - Reshma Kailath
- The Jenner Institute Laboratories, University of Oxford, UK
| | - Sean Elias
- The Jenner Institute Laboratories, University of Oxford, UK
| | | | - Andres Noe
- The Jenner Institute Laboratories, University of Oxford, UK
| | - Matthew Cairns
- London School of Hygiene & Tropical Medicine, London, UK
| | - Alison Lawrie
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Rachel Roberts
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Innocent Valéa
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Hermann Sorgho
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | | | | | | | | | - Katie J Ewer
- The Jenner Institute Laboratories, University of Oxford, UK
| | | | - Adrian V S Hill
- Centre for Clinical Vaccinology and Tropical Medicine, The Jenner Institute, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, UK; The Jenner Institute Laboratories, University of Oxford, UK.
| | - Halidou Tinto
- Unité de Recherche Clinique de Nanoro, Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso.
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