Malaria is an illness caused by a parasite (an animal or plant that lives in or on a host) that enters the human body through the bite of an infected mosquito. The purpose of this study is to find out about the safety of an experimental malaria vaccine and whether the vaccine causes humans to produce antibodies (proteins made by the body's immune system to help control or prevent infection). Four strengths of the vaccine will be tested. The lowest strength of the vaccine will be tested before the next higher strength is tested. Each dosage (shot) of vaccine will be given to 18 people in 4 dosage groups on Day 0, at 1 month and at 6 months. Two people in each dosage group will receive injections of a placebo (contains no medication). Participants will include 80 healthy adults between 18 and 40 years of age. Multiple blood draws will occur over the duration of the study. Participants will be involved in study related procedures for approximately 13 months.
This study is a phase I, double-blinded, placebo-controlled, dosage-escalation study of the safety and immunogenicity of EBA-175 RII-NG malaria vaccine administered intramuscularly. The vaccine is a recombinant Plasmodium falciparum (Pf) erythrocyte-binding antigen 175 kDa Region II-nonglycosylated (EBA-175 RII-NG) adsorbed to aluminum phosphate adjuvant. The study is being conducted at Baylor College of Medicine, Houston, Texas. Eighty healthy subjects, between the ages of 18 and 40 years, males and females, will be recruited from Houston, Texas, and will participate in the study for approximately 13 months. Subjects will be randomized to receive 3 doses of the vaccine or saline placebo by the intramuscular route in a 9:1 ratio at 0, 1 and 6 months. The safety and immunogenicity of ascending dosages of the vaccine will be assessed. Eighteen subjects will receive vaccine at each of the following dosage levels: 5, 20, 80 and 160 micrograms. Two subjects will receive placebo for each dosage level. Dosage escalation will proceed only after review of the 2-week safety data of the 2 initial doses of the prior dosage level. The primary study objective is to assess the safety and reactogenicity (tolerability) of ascending dosages of EBA-175 RII-NG vaccine among healthy subjects given in 3 intramuscular doses at 0, 1 and 6 months. The secondary study objective is to evaluate the immunogenicity of the EBA-175 RII-NG vaccine by measuring anti-EBA-175 RII-NG antibodies using enzyme-linked immunosorbent assay (ELISA), anti-parasite antibodies by indirect fluorescence antibody test (IFAT), inhibition of binding of EBA-175 RII-NG to red blood cells (RBCs), and inhibition of Pf growth in vitro.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
80
1.0 mg/mL (0.5 mg/0.5 mL per dose) aluminum as aluminum phosphate adjuvant; dosage 500 micrograms.
0.5 mL normal saline placebo. Sodium phosphate buffer (10 mM sodium phosphate and 150 mM sodium chloride).
White, translucent, cloudy, nonparticulate liquid suspension. Recombinant Plasmodium falciparum erythrocyte-binding antigen 175 kDa Region II-nonglycosylated (EBA-175 RII-NG) absorbed to aluminum phosphate adjuvant; dosage levels 5, 20, 80, and 160 micrograms.
Baylor College of Medicine - Molecular Virology and Microbiology
Houston, Texas, United States
Frequency and severity of injection site and systemic adverse events (AEs).
Time frame: Duration of study.
Relative binding inhibition of recombinant EBA-175 RII-NG to human RBCs in vitro in the presence of serum from immunized individuals.
Time frame: Days 0, 14, 28, 42, 180, and 194.
Anti-parasite antibodies by indirect fluorescence antibody test (IFAT).
Time frame: Days 0, 14, 28, 42, 180, and 194.
Anti-EBA-175 RII-NG antibody level by ELISA.
Time frame: Days 0, 14, 28, 42, 180, and 194.
Relative growth inhibition of Pf in human RBCs cultured in vitro in the presence of serum from immunized individuals.
Time frame: Days 0, 14, 28, 42, 180, and 194.
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