Open Label Phase 1 Study in Malaria Naive Adults of the Safety and Immunogenicity of Pfs25-EPA/Alhydrogel, a Transmission Blocking Vaccine Against Plasmodium Falciparum
Trial Snapshot
- Phase
- Phase 1
- Status
- Completed
- Enrollment
- 30
- Locations
- 2
- Primary Endpoint
- Incidence of local and systemic adverse events
Study Overview
Brief Summary
Background:
- The malaria vaccine Pfs25-EPA/Alhydrogel may help block malaria parasites from developing in mosquitoes. When a mosquito bites a vaccinated person, the vaccine should prevent parasites from developing in the mosquito. As a result, the mosquito will not spread malaria to the next person it bites. However, the vaccine will not directly prevent people from getting sick with malaria. Researchers want to test the safety of and response to this vaccine.
Objectives:
- To test the safety of the malaria vaccine Pfs25-EPA/Alhydrogel.
Eligibility:
- Healthy volunteers between 18 and 50 years of age.
Design:
- Participants will be screened with a medical history, physical exam, and blood tests.
- They will be assigned to a study group to have either two or three doses of the vaccine. Participants will have checkups after each dose of vaccine,
- The additional doses will be given 2 months or 2 and 4 months after the first vaccine.
- Participants will have regular blood tests to check the level of the response to the vaccine.
- They will be followed for up to 1 year after the last vaccine to have any additional tests as needed.
Detailed Description
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Prevention
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to 50 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- Not provided
Exclusion Criteria
- Not provided
Outcomes
Primary Outcomes
Incidence of local and systemic adverse events
Time Frame: All adverse events will be recorded though Day 28 after each vaccination. The frequency of systemic and local AEs will be summarized.
Subjects will be monitored for 30 minutes following each immunization. Subjects will return to the clinic on Days 3,7,14 and 28 following each vaccination for clinical assessments, and periodically thereafter until completion
Secondary Outcomes
- To determine the antibody response to the Pfs25 protein vaccines as measured by ELISA and transmission blocking assays, and the effect on antibody responses of a third dose at four months(ELISA testing will occur on vaccination days, 2 weeks after each vaccination, and periodically until study completion)