ELQ-300 is an experimental antimalarial medication. It is the first entry in a new class of antimalarials known as 4-quinolone-3-diarylethers.
ELQ-300 acts as an inhibitor of the mitochondrial cytochrome bc<sub>1</sub> complex (complex III in the electron transport chain) - A mechanism shared with some of the most potent fungicides known, the strobilurins. In preclinical studies with mice, ELQ-300 was found to be highly active against Plasmodium falciparum and Plasmodium vivax at all life cycle stages that play a role in the transmission of malaria, and to have good oral bioavailability.
Due to issues with crystallization, ELQ-300 was turned into a prodrug known as ELQ-331. ELQ-331 and two other similar drug candidates are currently in development.