Safety and Immunogenicity of Direct Venous Inoculation of a Radiation-attenuated PfSPZ Vaccine in Equatoguinean Adults
Condition: Malaria; Plasmodium Falciparum
MeSH terms: Malaria
Study type: Interventional
Phase: Phase 1

Summary: 
      This is a single center, randomized, placebo-controlled, double-blind trial to assess the
      safety and immunogenicity of PfSPZ Vaccine administered by direct venous inoculation (DVI).

      The study to be conducted in Baney District, Bioko Island, Equatorial Guinea (EG), will be to
      establish whether three doses of the higher regimen - three doses of 2.7x10^5 PfSPZ of the
      PfSPZ Vaccine administered at 8 week intervals - is as well-tolerated and efficacious in
      malaria exposed African adults as the five dose regimens. Specifically, the trial will
      address the following objectives: is the three dose regimen:

        1. Safe and well tolerated in Equatoguinean (EG) adults.

        2. As immunogenic in EG adults as is the five-dose regimen of 1.35x10^5 PfSPZ in Tanzanian
           and U.S. adults or as three-, four- and five-dose regimens of 2.7x10^5 PfSPZ being
           tested in Tanzanian, Malian and U.S. adults.

      In addition, as an exploratory objective, the volunteers in the EG trial will be followed
      longitudinally to measure the incidence of malaria during the initial six months following
      immunization, providing a preliminary assessment of efficacy.
    

Detailed description: 
      This is a single center, Phase 1, randomized, double-blind, placebo-controlled trial.
      Thirty-three healthy male volunteers, aged 18 to 35 years will be recruited into three
      groups. The first group will be comprised of 3 volunteers who will be vaccinated first before
      the rest for demonstration of safety. The safety volunteers will receive 2 escalating doses
      of PfSPZ vaccine at a two week interval, 1.35x10^5 and 2.7x10^5 PfSPZ. The second group of 14
      - 20 volunteers will receive three vaccinations of 2.7x10^5 PfSPZ that will be given at 0, 8
      and 16 weeks (in the Tanzania trial, volunteers will receive a five dose regimen at 0, 4, 8,
      12 and 18 weeks). The third group of 7 - 10 volunteers will act as control group for group 2
      and will receive three injections of normal saline at 0, 8 and 16 weeks respectively.

      Volunteers in groups 2 and 3 will only be injected when the Safety Monitoring Committee (SMC)
      provides clearance based on the results from the sentinel 3 volunteers (group 1). For groups
      2 and 3, five volunteers will be vaccinated with the first dose before the remaining
      volunteers are vaccinated on a subsequent day.

      The control volunteers will help better assess the occurrence of adverse events compared to
      background disease patterns that occur in this tropical area. The decision to dose escalate
      in group 1 and to immunize a larger number of volunteers in group 2 in Bioko will be made
      with full knowledge of all safety data generated in other ongoing trials where the PfSPZ
      Vaccine is being tested.
    

Intervention name(s): PfSPZ Vaccine; Normal Saline
Intervention type(s): Biological; Other
Intervention description(s): Aseptic, purified, metabolically active, non-replicating (live, radiation attenuated) cryopreserved Plasmodium falciparum sporozoites vaccine; 0.9% Sodium chloride solution for injection
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: PfSPZ Vaccine