K13 580Y allele not linked to increased P. falciparum recrudescences in artesunate-treated Aotus

Concerns about impending failure of artemisinin compounds (ART) have grown with global use of ART-based combination therapy (ACT) against malaria. WHO has defined Plasmodium falciparum resistance to ART as prolonged parasite clearance half-life in vivo (t1/2) plus the presence of certain K13 Kelch-propeller substitutions, e.g. C580Y. Recrudescences and fever clearance times after ART monotherapy, however, have not correlated well with these criteria. We have crossed K13 C580 wild-type and 580Y-mutant parasites for ART studies in Aotus. Artesunate treated C580- but not 580Y-infections recrudesced requiring retreatment, and K13 type had little or no effect on t1/2. These results challenge K13 and t1/2 variations as markers of increased resistance to ART per se and emphasize the need for effective partner drugs in ACTs. 57 samples, no replicates, Plasmodium falciparum various clones.