This Phase 1/2 study, conducted in malaria-naïve adults in the United States, was designed to determine the safety, immunogenicity, and initial efficacy of the recombinant liver-stage antigen-1 (LSA1) vaccine candidate—also referred to as falciparum malaria protein-11 (FMP011)—when adjuvanted in GlaxoSmithKline’s (GSK) AS01B.
Volunteers were randomized into two dose-escalating groups (10 µg and 50 µg), and received multiple intramuscular vaccinations of LSA1 adjuvanted with 0.5 mL AS01B on a 0,1-month schedule.
The study was designed with two objectives:
- Assess the safety and reactogenicity of LSA1/ AS01B in malaria-naïve adults by monitoring for occurrence of solicited signs and symptoms, occurrence of unsolicited symptoms, and the occurrence of serious adverse events during the study period.
- Assess the efficacy of the candidate vaccine against sporozoite challenge with Plasmodium falciparum, and assess cell-mediated immune response.
Outcomes/Next steps: Findings were published in Vaccine in 2010, and presented in part at the American Society of Tropical Medicine and Hygiene Annual Meeting in 2006.
LSA1/AS01B was found to be well-tolerated, with low systemic reactogenicity in subjects. Despite its immunogenicity, LSA1/AS01B did not offer efficacy against Plasmodium falciparum.
Cummings JF, Spring MD, Schwenk RJ, Ockenhouse CF, Kester KE, et al. Recombinant liver stage antigen-1 (LSA-1) formulated with AS01 or AS02 is safe, elicits high titer antibody and induces IFN-γ/IL-2 CD4+ T cells but does not protect against experimental Plasmodium falciparum infection. Vaccine. 2010;28(31):5135-5144.