The goal of the study is to test the efficacy using a homologous CHMI of this vaccine candidate early in the development path in a population living in malaria-endemic areas.
In the previous Phase Ia and Ib trials, no efficacy endpoints were defined, and therefore there is currently no data on the SUM-101 vaccine efficacy. The proposed clinical trial will enrol malaria pre-exposed healthy adults and will be the second trial where the IMP will be administered to healthy adult participants in Tanzania with some pre-existing immunity against malaria.
The vaccination part of this study will be performed in a randomised, double-blinded, controlled design to evaluate the safety, reactogenicity and immunogenicity of the candidate malaria vaccine SUM-101 (MSP1 with GLA-SE as adjuvant). Given that SUM-101 is a malaria vaccine with an important blood-stage component, we propose to use CHMI with the 3D7 P. falciparum strain-infected red blood cells to establish initial vaccine efficacy data after the third vaccination in a malaria-exposed population.
Written informed consent obtained before any study procedure.
Literate participants aged ≥18 - ≤45 years of African origin.
Female and male participants willing to practice effective contraception from 4 weeks before 1st vaccination (female participants only) and up to 12 weeks after the last vaccination or CHMI (female and male participants)
Female participants must be willing to undergo multiple serum pregnancy tests.
Previous participation in any malaria vaccine trial in the last 3 years.
Participation in any other clinical trial involving investigational medicinal products within 30 days prior to the screening assessment.
Previous history of drug or alcohol abuse interfering with normal social function within one year prior to enrolment.
Previous vaccination with a rabies vaccine.
Parallel
SUM-101
Biological/VaccineOnce randomised to either the SUM-101 or the rabies control vaccine, the participant will always receive the same dose of the same compound (150 µg MSP1 protein dissolved in 0.9% NaCl with 250 µl (5µg) of adjuvant GLA-SE and there are no dose adjustments foreseen. The three vaccine doses will be applied in 4-week intervals on day 0, day 28 and day 56.
CHMI
Other interventionExperimental intervention: The participants will receive a target dose of 2,800 viable intraerythrocytic P. falciparum 3D7 parasites, in a volume of 2 mL injectable saline. The erythrocytes will be thawed, resuspended and viability will be calculated. The total erythrocyte number will be between \~3.9×106 and \~5.2×108 (average: \~4.55×108) per dose with ≥80% (\~3.64×108) P. falciparum ring-stage parasites and around 34% (\~1.24×108) viability. This number of viable P. falciparum ring-stage parasites will be diluted to establish 2800 per syringe that will be administered. Challenge dose will be administered to all volunteers as an intravenous injection at the clinical site following instructions in an established SOP. The parasites injected in each volunteer will be quantified retrospectively using qPCR analysis. The parasites injected in each volunteer will be quantified retrospectively using qPCR analysis. No dose adjustments are foreseen. As described in the protocol
Verorab®
Biological/VaccineOnce randomised the participant will receive the or Verorab® and there are no dose adjustments foreseen. The three vaccine doses will be applied in 4-week intervals on day 0, day 28 and day 56.
Efficacy- Time to diagnosis
Blood-stage efficacy of the SUM-101 vaccine against 3D7 clone parasites in a CHMI model in healthy malaria-exposed adult volunteers, measured as time to diagnosis in the vaccine arm compared to controls. Time to diagnosis is defined as the number of days from challenge to treatment
Frequency of local and systemic solicited adverse events
Safety of SUM-101 vaccine in healthy malaria-exposed adults as assessed by the frequency of local and systemic solicited adverse events (AEs)
Frequency of local and systemic unsolicited adverse events
Safety of SUM-101 vaccine in healthy malaria-exposed adults as assessed by the frequency of local and systemic unsolicited adverse events
Frequency of any serious adverse events (SAE)
Safety of SUM-101 vaccine in healthy malaria-exposed adults as assessed by any serious adverse events (SAE)
Immunogenicity to MSP1-specific IgM antibody levels measured by ELISA
Humoral immunogenicity of SUM-101 in malaria-exposed adults assessed as MSP1-specific IgM antibody levels measured by serum ELISA in sera collected at Day 0 (pre-vaccination) and Day 84 (Pre-CHMI).
Immunogenicity assessed as antibody-mediated complement fixation activity.
Humoral immunogenicity of SUM-101 in malaria-exposed adults assessed as antibody-mediated complement fixation activity.
Antibody-mediated complement fixation activity
Humoral immunogenicity of SUM-101 in malaria-exposed adults assessed as antibody-mediated complement fixation activity.
Antibody-dependent respiratory burst (ADRB) activity
Humoral immunogenicity of SUM-101 in malaria-exposed adults assessed as antibody-dependent respiratory burst (ADRB) activity.
Comparison of P. falciparum in vivo parasite growth rates
Blood-stage efficacy of SUM-101 malaria vaccine candidate against 3D7 clone parasites in a CHMI model in healthy malaria-exposed adult volunteers, assessed as a comparison of P. falciparum in vivo parasite growth rates (such as parasite multiplication rate, maximum parasitemia, area under the curve, HRP2 levels or total parasites calculation and other outcomes based on parasite growth) in SUM-101 versus Verorab® arm.
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European Vaccine Initiative
Lead sponsor
Luxembourg Institute of Health
Collaborator
Ifakara Health Institute
Collaborator
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