Impact on Malaria Parasite Multiplication Rates in Infected Volunteers of the Protein-in-Adjuvant Vaccine AMA1-C1/Alhydrogel+CPG 7909

摘要: Background Inhibition of parasite growth is a major objective blood-stage malaria vaccines. The in vitro assay inhibitory activity (GIA) widely used as surrogate marker for vaccine efficacy the down-selection candidate Here we report first study to examine relationship between vivo Plasmodium falciparum rates and GIA humans experimentally infected with malaria. Methods In this phase I/IIa open-label clinical trial five healthy malaria-naive volunteers were immunised AMA1/C1-Alhydrogel+CPG 7909, together three unvaccinated controls challenged by intravenous inoculation P. erythrocytes. Results A significant correlation was observed multiplication rate 48 hours (PMR) both vaccine-induced growth-inhibitory (Pearson r = −0.93 [95% CI: −1.0, −0.27] P 0.02) AMA1 antibody titres group −0.99, −0.25] 0.02). However immunisation failed reduce overall mean PMR comparison (vaccinee 16 fold 12, 22], control 17 [CI: 0, 65] 0.70). Therefore no impact on pre-patent period (vaccine median 8.5 days [range 7.5–9], 9 7–9]). Conclusions Despite observation human experimental infection association rate, did not translate into any observable clinically relevant effect small volunteers. Trial Registration ClinicalTrials.gov [NCT00984763]