Initial Study of Malaria Vaccine Pfs25-EPA/Alhydrogel(Registered Trademark)

A vaccine to interrupt malaria transmission would be a valuable tool for local elimination or eradication of this disease. Pfs25, a surface antigen of ookinetes in the mosquito stage of P. falciparum, is a lead candidate for a malaria transmission blocking vaccine. Recombinant Pfs25 has been conjugated to Pseudomonas aeruginosa ExoProtein A (EPA), and adjuvanted with Alhydrogel(Registered Trademark). This open label, dose escalating Phase 1 study in malaria naive adults, conducted at Johns Hopkins Bloomberg School of Public Health Center for Immunization Research (CIR) in Baltimore, Maryland, will determine initial safety and immunogenicity of the vaccine given on a 2-dose,3-dose, or 4-dose schedule. Thirty (30) volunteers will be enrolled, with 5 receiving the low dose (8 micro g of conjugated Pfs25), 5 receiving the middle dose (16 micro g of conjugated Pfs25), and 20 receiving the high dose (47 micro g of conjugated Pfs25). The high dose group will receive either 2, 3 or 4 doses of vaccine, on a 0, 2, 4 and 10 month vaccination schedule. Volunteers will be followed for 12 months following the last vaccination. Safety outcomes will be local and systemic adverse events (AEs). Immunogenicity outcomes will be antibody responses as measured by ELISA, transmission blocking in a standard membrane feeding assay, and B and T cell responses.