Na-GST-1 is a protein expressed during the adult stage of the Necator americanus hookworm life cycle that is thought to play a role in the parasite's degradation of host hemoglobin for use as an energy source. Vaccination with recombinant Na-GST-1 has protected dogs and hamsters from infection in challenge studies. This study will evaluate the safety and immunogenicity of administering Na-GST-1 with or without the CpG 10104 immunostimulant to healthy Gabonese adults living in an area of endemic hookworm infection.
Double blind, randomized, controlled, dose-escalation Phase 1 clinical trial in hookworm-exposed adults aged 18 to 50 years living in the area of Lambaréné, Gabon. Participants will receive three doses of the assigned vaccine(s) delivered intramuscularly (deltoid) on approximately Days 0, 56, and 112. Safety will be measured from the time of each study vaccination (Day 0) through 14 days after each study vaccination by the occurrence of solicited injection site and systemic reactogenicity events. Unsolicited non-serious adverse events (AEs) will be collected from the time of the first study vaccination through approximately 1 month after each study vaccination. New-onset chronic medical conditions and Serious Adverse Events (SAEs) will be collected from the time of the first study vaccination through approximately 9 months after the final study vaccination (final visit). Clinical laboratory evaluations for safety will be performed on venous blood collected approximately 14 days after each vaccination. Immunogenicity testing will include IgG antibody responses to each vaccine antigen, by a qualified indirect enzyme-linked immunosorbent assay (ELISA), on serum or plasma obtained prior to each study vaccination and at time points after each vaccination; the functional activity of vaccine-induced antibodies will be assessed by in vitro enzyme neutralization assays. Recruitment and enrollment into the study will occur on an ongoing basis, with each group being recruited and vaccinated in sequence. 24 subjects will be enrolled into 2 groups: * Group 1 (n=12): * 8 subjects will receive 30 µg Na-GST-1 plus 500 µg CPG 10104 delivered by IM injection in the deltoid muscle * 4 subjects will receive 100 µg Na-GST-1 delivered by IM injection in the deltoid muscle * Group 2 (n=12): * 8 subjects will receive 100 µg Na-GST-1 plus 500 µg CPG 10104 delivered by IM injection in the deltoid muscle * 4 subjects will receive 100 µg Na-GST-1 delivered by IM injection in the deltoid muscle
Study Type
INTERVENTIONAL
Allocation
Centre de Récherches Médicales de Lambaréné
Lambaréné, Gabon
Vaccine-related Adverse Events
1\. To evaluate the safety and reactogenicity of two different dose concentrations of Na-GST-1/Alhydrogel® administered with or without CPG 10104 in healthy Gabonese adults.
Time frame: Day 380
Anti-Na-GST-1 IgG Antibody Level on Day 126
1\. To determine the dose/formulation that results in the highest level of anti-Na-GST-1 IgG antibody approximately 14 days after the final vaccination.
Time frame: Day 126
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RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
24