Prospective observational study of dihydroartemisinin-piperaquine treatment of vivax malaria in North Sumatera, Indonesia

Abstract

Objectives. Plasmodium vivax malaria treated by dihydroartemisinin-piperaquine (DHA-PPQ) in Indonesia remains a challenge. Plasmodium falciparum resistance to DHA-PPQ was documented in Asia and it is suspected that this will also be a concern for P. vivaxmalaria. Thus it is needed to test the sensitivity of P. vivax on a regular basis. Parasite clearance time (PCT) and molecular markers of resistance are efficient sentinel tools for this goal. Methods. A prospective observational study was conducted at North Labuhan Batu Regency (Sumatra). The outcome were the clinical and parasitological efficacy of the 3-day DHA-PPQ therapy corrected by PCR and the prevalence of Pvmdr1, PvK12 and PvPM4 molecular markers of chloroquine and DHA-PPQ resistance. Results. During the 6-months study period, 100 patients were included and 6 were lost to follow-up. Ninety-four patients were included in the per-protocol analysis. The parasite clearance half-life increased over 18h in 8.5% of the cases while no clinical recurrence were observed during the Day-28 follow-up. None of the molecular marker of ACT resistance were detected among the samples tested. Conclusions. This study highlighted the need for active surveillance of ACT efficacy against P. vivax malaria in Indonesia, using simple method such as PCT during observational studies, as it may provide a cost-effective early warning signal.