High Prevalence of Plasmodium falciparum K13 Mutations in Rwanda Is Associated With Slow Parasite Clearance After Treatment With Artemether-Lumefantrine

In Southeast Asia, mutations in the Plasmodium falciparum K13 gene have led to delayed parasite clearance and treatment failures in patients with malaria receiving artemisinin combination therapies. Until recently, relevant K13 mutations had been mostly absent from Africa. Between 2018 and 2019, a phase 2 clinical study with 186 patients was conducted in Mali, Gabon, Ghana, Uganda, and Rwanda. Patients with malaria were randomized and treated with artemether-lumefantrine or cipargamin. Here we report an allele frequency of 22% for R561H in Rwanda and associated delayed parasite clearance. Notwithstanding, efficacy of artemether-lumefantrine remained high in Rwanda, with a 94.4% polymerase chain reaction–corrected cure rate.