New malaria vaccine with 75% efficacy – a potential game changer – Health Policy Watch

A new R21/Matrix-M malaria vaccine shows 75% efficacy in a phase 2b study – a potentially breakthrough result compared to the WHO-approved RTS,S/AS01 (RTS,S) vaccine.

The WHO has said it will continue rolling out its approved RTS,S vaccine, despite the promise of a new malaria vaccine candidate, the R21/Matrix-M, showing 75% efficacy in a recent phase 2b study – almost twice that of the recently approved RTS,S vaccine.

At a WHO press conference on Thursday, Dr. Matshidiso Moeti, WHO Regional Director for Africa, the results of the R21/Matrix-M vaccine published on Wednesday in the Lancet, but said the rollout of the RTS,S vaccine would continue.

The R21/Matrix M vaccine candidate has yet to be clinically tested against the RTS,S vaccine in a large-scale field trial, Moeti said.

“We can look forward to the vaccine moving through all phases of clinical trials, and then field testing with the RTS,S vaccine once the data finally comes in,” she said.

The R21/Matrix M, she said, “can be an additional tool to join the vaccine that has been shown to be reasonably effective, the RTS,S vaccine, in reducing severe malaria and childhood deaths.”

Just three months ago, the Gates Foundation said that was the case Withdrawal of financial support from the introduction of the RTS, p vaccine because of its low efficacy ratings and would prioritize its investments in classic interventions such as insecticide-treated bed nets.

The RTS,S vaccine, the first to be approved by the WHO in October 2021was tested on around 800,000 infants and children and demonstrated a 40% fewer malaria episodes and 31% fewer in severe malaria infections in a pilot project in three countries.

The WHO later said it would spend $160 million to roll out the vaccine on a larger scale by 2025, starting in Ghana, Kenya and Malawi.

“The aim is to license this vaccine for widespread use in the next year”

Midwife treating a baby with severe malaria.

But if the results of R21/Matrix-M hold up in a Phase 3 trial – which the researchers hope will yield enough results for approval by next year – this newer vaccine could very well replace the other vaccine and turn WHO’s original plans upside down.

In your Findings reported in The Lancet Infectious DiseasesUniversity of Oxford researchers and their partners found that one dose of vaccine had at least 75% efficacy in preventing episodes of malaria one year after a primary three-dose regimen – compared to about 40% for the WHO-approved RTS,S vaccine.

This higher efficacy also meets the goal of the WHO’s Malaria Vaccine Technology Roadmap – once considered largely ambitious. The R21/Matrix-M vaccine previously had an efficacy of 77% during the first 12 months of the randomized, controlled vaccine study with a total of 450 participants aged five to 17 months recruited in the Nanoro region, Burkina Faso. shown.

In the most recent study with a booster dose of R21/Matrix-M, about 409 of the original 450 participants returned after one year to receive the booster, with a similar result. The study will continue for a further two years to assess both the potential value of additional booster doses and longer-term safety.

Halidou Tinto, professor of parasitology and lead investigator on the study, said it was “fantastic to see such high efficacy again after a single booster dose of the vaccine. We are currently part of a very large phase III study aimed at approving this vaccine for widespread use over the next year.”

Adrian Hill, co-author of the publication, Professor of Vaccinology and Director of the Jenner Institute at the University of Oxford, was also pleased to “find that a standard four-dose immunization regimen can now, for the first time, achieve the high levels of efficacy over two years which has been a target for malaria vaccines for so many years.”

mechanism of action

Research into new drugs against malaria

R21/Matrix-M is a pre-erythrocyte malaria vaccine candidate being developed by Oxford University scientists and manufactured by the Serum Institute of India.

It is produced by expressing recombinant hepatitis surface antigen virus-like particles in Hansenula polymorpha, a microorganism naturally occurring in some insects and foods. The study was funded by the EDCTP2 program, which is supported by the European Union, the Wellcome Trust and the NIHR Oxford Biomedical Research Centre.

RTS,S, a recombinant protein-based malaria vaccine, aims to trick the immune system into fighting the early stages of malaria, when the Plasmodium falciparum parasite enters the human host’s bloodstream through a mosquito bite and infects liver cells .

The vaccine is designed to prevent the parasite from infecting the liver, where it can mature, multiply, re-enter the bloodstream and infect red blood cells, which can lead to symptoms of the disease.

It is the result of 30 years of research and development by GSK and through a partnership with PATH with the support of a network of African research centres. According to the WHO, between 2001 and 2015, the Bill and Melinda Gates Foundation provided catalytic funding for the late-stage development of RTS,S.

Credit: Elizabeth Poll/MMV, MMV.