Emoquine-1: A Hybrid Molecule Efficient against Multidrug-Resistant Plasmodium Parasites, Including the Artemisinin-Resistant Quiescent Stage, and Also Active In Vivo.

To challenge the multidrug resistance of Plasmodium falciparum malaria parasites, new hybrid compounds were synthesized and evaluated against laboratory strains and multidrug-resistant clinical isolates. Among these hybrids, emoquine-1 was the most active on proliferative P. falciparum, with IC50 values in the range of 20-55 nM and a high selectivity index with respect to mammalian cells. This drug retained its activity on several multiresistant field isolates from Cambodia and Guiana, exhibited no cross-resistance to artemisinin, and is also very active against the quiescent stage of the artemisinin-resistant parasites, three features that constitute the gold standard for new antimalarial drugs. In vivo, emoquine-1 is active against Plasmodium vinckei petteri at 25 mg/kg/d per os and by the intraperitoneal route at 1-5 mg/kg/d, with total cure at 10 mg/kg/d, making emoquine-1 an ideal candidate to fight Plasmodium parasites resistant to artemisinin-based combination therapies (ACTs) with a capacity to eliminate persistent parasites.