SMC and RTS,S vaccine in combination show considerable advantage in preventing malaria
Phase III trial results just published in the Lancet Infectious Diseases
MMV welcomes the news that a combination of seasonal malaria chemoprevention (SMC with sulfadoxine-pyrimethamine and amodiaquine – SPAQ) and the seasonally delivered RTS,S/AS01E vaccine provide significant added protection against malaria in young children during the malaria season, as compared to either intervention alone.
This Phase III trial builds on the landmark study published in the NEJM in 2021 that already demonstrated the superior protective efficacy of combining the two interventions for a 3-year period. The latest trial (A.Dicko et al) published in the Lancet Infectious Diseases confirmed that the added protection provided by the combination can be sustained for a full 5 years, 2 more than the previous study.
The phase III trial was conducted in two sites in Mali and Burkina Faso, where malaria is the leading cause of death among children under 5 years. A total of 6,861 infants between the ages of 5 and 17 months were initially enrolled in the trial 5 years ago; and 94% of the 5,433 who completed the initial 3-year follow-up were re-enrolled in a 2-year extension study. Hospitalisation and death rates were lower for the combination than either SMC or the vaccine alone and no safety signals were detected.
The authors of the study point out that the relative efficacy in reducing clinical malaria for the vaccine alone appeared lower versus SMC in year 5. This difference was greatest in Burkina Faso, where a fifth round of SMC was given at the end of the malaria season. These observations underscore the benefits of combining the vaccine with SMC, and the benefit of tailoring the number of courses of SMC to the duration of the malaria season.
MMV has been working since 2012 on the use of SPAQ in SMC campaigns to prevent malaria among young children. In June 2022, WHO updated its recommendations on SMC to include use among young children at high risk of severe malaria in areas with both seasonal and year-round transmission. The updated guidelines do not specify age restrictions, transmission intensity thresholds, numbers of doses or cycles or specific drugs.
To date, 1 billion SPAQ treatments have been delivered as part of SMC campaigns, protecting more than 48 million children in 17 countries, making it one of the most successful and effective antimalarial campaigns ever rolled out in Africa. In the context of such large programmes, particularly when combining with another intervention, such as vaccination, cost-effectiveness is a crucial consideration. The benefits of adding SMC to malaria vaccination detailed above come at an average 5-year cost (five, 4-month courses) of $18 including implementation costs.
“We are delighted that the combination of SMC and RTS,S has shown strong and durable results,” said Dr David Reddy, CEO of MMV. “Alongside developing new interventions to address unmet medical needs in malaria, optimizing the combined use of the available prevention and curative interventions, with a focus on efficacy, safety and cost-effectiveness, remains a priority for MMV and all partners involved in product innovation for malaria control and elimination.