The Novel bis-1,2,4-Triazine MIPS-0004373 Demonstrates Rapid and Potent Activity against All Blood Stages of the Malaria Parasite.

Novel bis-1,2,4-triazine compounds with potent activity against Plasmodium falciparum parasites were recently identified. The bis-1,2,4-triazines represent a unique antimalarial pharmacophore and are proposed to act by a novel but as-yet-unknown mechanism of action. This study investigated the activity of the bis-1,2,4-triazine MIPS-0004373 across the mammalian life cycle stages of the parasite and profiled the kinetics of activity against blood and transmission stage parasites and . MIPS-0004373 demonstrated rapid and potent activity against P. falciparum, with excellent activity against all asexual blood stages. Prolonged drug exposure failed to generate stable resistance , suggesting a low propensity for the emergence of resistance. Excellent activity was observed against sexually committed ring stage parasites, but activity against mature gametocytes was limited to inhibiting male gametogenesis. Assessment of liver stage activity demonstrated good activity in an P. berghei model but no activity against Plasmodium cynomolgi hypnozoites or liver schizonts. The bis-1,2,4-triazine MIPS-0004373 efficiently cleared an established P. berghei infection , with efficacy similar to that of artesunate and chloroquine and a recrudescence profile comparable to that of chloroquine. This study demonstrates the suitability of bis-1,2,4-triazines for further development toward a novel treatment for acute malaria.