This Phase 1/2a study, conducted in malaria-naïve adults in the United States, aimed to evaluate the immunogenicity, safety, and protective efficacy of the Plasmodium vivax circumsporozoite protein-based vaccine VMP001 adjuvanted in GlaxoSmithKline’s (GSK) AS01B.
Subjects were randomized among three groups, each receiving multiple intramuscular vaccinations of VMP001 at one of three dose levels (15 µg, 30 µg, and 60 µg) in 500 µL of AS01B.
The study was designed with two objectives:
- Assess the safety and reactogenicity of the VMP001/AS01B vaccine in malaria-naïve adults by monitoring for occurrence of solicited signs and symptoms during a seven-day follow-up period after each vaccination, occurrence of unsolicited symptoms during a 28-day follow-up period after each vaccination, and the occurrence of serious adverse events after the first dose of vaccine during the study follow-up period.
- Quantify the humoral immune response via anti-VMP001 antibody titer.
Findings were published in PLoS Neglected Tropical Diseases in 2016.
VMP001/AS01B was found to be safe and well-tolerated. Despite its high immunogenicity, it did not offer protective efficacy against Plasmodium vivax.
Based on the outcomes of this study, the PATH Malaria Vaccine Initiative did not make further investments.
Bennett JW, Yadava A, Tosh D, Sattabongkot J, Komisar J, et al. Phase 1/2a trial of Plasmodium vivax malaria vaccine candidate VMP001/AS01B in malaria-naive adults: safety, immunogenicity, and efficacy. PLoS Neglected Tropical Diseases. 2016;10(2):e0004423