Study profiles. * Tanzania: hemoglobin <5.0 g/dL (2 patients), unable to swallow drug (1 patient), withdrawal of consent (2 patients), blood withdrawal not possible (1 patient), >9’999 parasites per 200 white blood cells (1 patient). Cambodia: withdrawal of consent (1 patient in each study). ** In 4 patients only DHA but no AS could be detected. *** Tanzania: 4 late clinical failures, 3 late parasitological failures and 1 late clinical and parasitological failure. Cambodia: 3 late parasitological failures in Phnom Dék and 1 late clinical failure in Pramoy. AM: artemether; AS: artesunate; DHA: dihydroartemisinin; LF: lumefantrine; MQ: mefloquine; PPQ: piperaquine.