This study is designed to be executed in two steps to achieve the primary efficacy objective:~The first step is a Phase 1b safety study, involving injections in a small safety subgroup for each dose before age-de-escalation into the younger age group and then proceeding to the second step of dosing the corresponding injection in the larger Phase 2b efficacy cohort.~Vaccination of the Phase 2b cohort will require an acceptable reactogenicity data over the first week following the corresponding vaccination of the older and younger age groups in the Phase 1 subgroup. The study DSMB will be charged with this review and ensuring that vaccination proceeds only if the reactogenicity profile meet study go criteria (Table 1).~The objectives of each phase are:~Phase 1b: The primary objective is to assess the safety and tolerability of the vaccine for each injection. The secondary objective is to evaluate the immune response to the vaccine and safety for up to 12 months after the first dose.~Phase 2b: The primary objective is to assess the efficacy in young children* against clinical malaria** during one transmission season. The timeline for the primary analysis assessment is from 14 days to 6 months after Dose 3.~Should the primary analysis data demonstrate that the vaccine gives good efficacy, a boost vaccination will be programmed to be administered to willing subjects before the start of the subsequent transmission season. The study protocol will be amended with the precise details in this event.
Two-arm, randomized, double-blinded and controlled clinical trial to first assess the safety and tolerability of the vaccine in a Phase 1b trial and proceed to assess its efficacy against clinical malaria in young children living in highly seasonal malaria areas of Mali