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Safety and Immunogenicity of a Recombinant Plasmodium falciparum AMA1 Malaria Vaccine Adjuvanted with Alhydrogel™, Montanide ISA 720 or AS02

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posted on 18.12.2008 by Meta Roestenberg, Ed Remarque, Erik de Jonge, Rob Hermsen, Hildur Blythman, Odile Leroy, Egeruan Imoukhuede, Soren Jepsen, Opokua Ofori-Anyinam, Bart Faber, Clemens H. M. Kocken, Miranda Arnold, Vanessa Walraven, Karina Teelen, Will Roeffen, Quirijn de Mast, W. Ripley Ballou, Joe Cohen, Marie Claude Dubois, Stéphane Ascarateil, Andre van der Ven, Alan Thomas, Robert Sauerwein


Plasmodium falciparum Apical Membrane Antigen 1 (PfAMA1) is a candidate vaccine antigen expressed by merozoites and sporozoites. It plays a key role in red blood cell and hepatocyte invasion that can be blocked by antibodies.

Methodology/Principal Findings

We assessed the safety and immunogenicity of recombinant PfAMA1 in a dose-escalating, phase Ia trial. PfAMA1 FVO strain, produced in Pichia pastoris, was reconstituted at 10 µg and 50 µg doses with three different adjuvants, Alhydrogel™, Montanide ISA720 and AS02 Adjuvant System. Six randomised groups of healthy male volunteers, 8–10 volunteers each, were scheduled to receive three immunisations at 4-week intervals. Safety and immunogenicity data were collected over one year. Transient pain was the predominant injection site reaction (80–100%). Induration occurred in the Montanide 50 µg group, resulting in a sterile abscess in two volunteers. Systemic adverse events occurred mainly in the AS02 groups lasting for 1–2 days. Erythema was observed in 22% of Montanide and 59% of AS02 group volunteers. After the second dose, six volunteers in the AS02 group and one in the Montanide group who reported grade 3 erythema (>50 mm) were withdrawn as they met the stopping criteria. All adverse events resolved. There were no vaccine-related serious adverse events. Humoral responses were highest in the AS02 groups. Antibodies showed activity in an in vitro growth inhibition assay up to 80%. Upon stimulation with the vaccine, peripheral mononuclear cells from all groups proliferated and secreted IFNγ and IL-5 cytokines.


All formulations showed distinct reactogenicity profiles. All formulations with PfAMA1 were immunogenic and induced functional antibodies.

Trial Registration

Clinicaltrials.gov NCT00730782