Discovery of long-acting, chemoprotective antimalarial compounds

To discover leads for next-generation chemoprotective antimalarial drugs, we tested >500,000 compounds for their ability to inhibit liver-stage development of luciferase-expressing Plasmodium parasites (681 with an IC50 < 1 µM). Cluster analysis identified potent and previously unreported scaffold families as well as other series previously associated with chemoprophylaxis. Further testing through multiple phenotypic assays that predict stage-specific and multispecies antimalarial activity revealed compound classes that are likely to provide symptomatic relief from blood-stage and others that only prevent malaria. Target identification using functional assays, in vitro evolution or metabolic profiling of the most potent blood stage-active scaffolds revealed multiple mitochondrial inhibitors but also compounds with likely new mechanisms of action. The total dataset provided hundreds of new chemotypes and scaffold families (compounds sharing a core structure) that may be used in further drug development for the treatment and prevention of malaria. Here we propose to perform hit to lead optimization on 1-2 scaffold families per year, synthesizing approximately ~750 compounds. Select compounds (10%) will be tested for microsomal stability, protein binding, hERG, and CYP inhibition. Pharmacokinetic and prophylactic animal model testing will be performed on ~10 compounds per year. In addition, we will explore whether promising leads can be converted to a prodrug form that can be given as intramuscular injection which provides long- lasting chemoprevention. Hit to lead optimization will be accompanied by investigation into the mechanism of action of six scaffold families using a suite of different methods including in vitro evolution and whole genome analysis. 

NIH Project details

Drug-based Strategies
Product Development

Mar 2020 — Feb 2025

$2.2M

United States