New Phase 3 Trial Data Confirm the Uniquely High Efficacy and Good Safety Profile of the R21/Matrix-M™ Malaria Vaccine in African Children

Published February. 22. 2024

Phase 3 Trial data results of The R21/Matrix-M™ vaccine developed by Oxford University and Serum Institute of India Pvt Ltd, leveraging Novavax’s Matrix-M™ adjuvant confirmed high efficacy and supported regulatory approvals and licensure in several African countries. Designed in 2011 as a potential improvement on the RTS, S/AS01 malaria vaccine, the R21/Matrix-M™ vaccine showed promising results in a phase II trial in Burkina Faso, achieving the WHO-specified target of 75% efficacy in African children. Recent WHO endorsement will lead to the initial rollout of R21/Matrix-M™ in the coming months. These new results have been published in The Lancet.

The trial investigators immunized over 4800 young children in Burkina Faso, Kenya, Mali, and Tanzania and found an average vaccine efficacy of 78% over the first year of follow-up across all sites in the 5-17-month-old age group. Safety data from the trial have been reassuring, with no serious adverse events linked to immunization. No other vaccine has reported over 55% efficacy in the same age group. A booster dose at a year maintained good efficacy over the following 6-12 months. The vaccine also reduced infection rates in children measured at 12 and 18 months after vaccination, suggesting a potentially beneficial effect in reducing malaria transmission.

The R21/Matrix-M™ vaccine was well tolerated, with injection site pain and fever as the most frequent adverse events. The number of adverse events of special interest and serious adverse events did not significantly differ between the vaccine groups, and there were no treatment-related deaths.

Malaria, the largest cause of death in young African children, claims over 600,000 lives globally each year. Two vaccines have recently achieved World Health Organization (WHO) prequalification, with initial deployments starting early this year.

Professor Adrian Hill, chief investigator of the R21/Matrix-M™ phase 3 trial, stated, “The continued high efficacy of this new vaccine in field trials is very encouraging and consistent with the high efficacy and excellent durability observed in a smaller four-year phase IIb trial. These data support an important role for the unique high-density nanoparticle display of the conserved repeat region of the malaria parasite circumsporozoite protein, a feature in the design of the R21 vaccine, in providing such high vaccine efficacy and, thereby, an important new tool for malaria control.”

Significantly increased immune responses to the R21/Matrix-M™ vaccine and slightly higher vaccine efficacy were observed in 5-17-month-olds compared to 18-36-month-olds malaria vaccines, supporting planned vaccine deployment initially from 5 months of age in young African children.

The vaccine is licensed to the Serum Institute of India (SII), the world’s largest vaccine manufacturer and a long-term partner of the University of Oxford. Matrix-M™ adjuvant is manufactured by Novavax AB and provided to Serum Institute of India for formulation into the final vaccine drug product.

Adar Poonawalla, CEO, Serum Institute of India, remarked, “The Lancet study on R21/Matrix-M™ Phase 3 trials marks a significant advancement in our battle against this global threat. Our collaboration with the University of Oxford has been instrumental in developing the R21/Matrix-M™ malaria vaccine. We are dedicated to making this vaccine available, especially in Africa, where malaria poses a substantial threat to millions of lives, bringing us closer to a malaria-free world.”

Professor Alassane Dicko, Principal Investigator in Mali of the R21/Matrix-M™ vaccine, shared, “It has been very exciting to generate high efficacy data with the new R21/Matrix-M™ vaccine so quickly. I predict that this vaccine should be very impactful in preventing malaria deaths in African children.”

John C Jacobs, CEO of Novavax, emphasized, “Approximately 1,300 children die from malaria every day, a staggering statistic for a preventable disease. The R21/Matrix-M™ Phase 3 efficacy data published in The Lancet reinforce the potential of R21/Matrix-M™ vaccine to protect children against this disease. We are proud of the role of Novavax’s patented saponin-based Matrix-M™ adjuvant, which has been demonstrated to enhance the immune response, in the outcome of this clinical trial and are eager to see the realized impact of the vaccine when it is rolled out globally.”

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