Efficacy of chloroquine + sulfadoxine–pyrimethamine, mefloquine + artesunate and artemether + lumefantrine combination therapies to treat Plasmodium falciparum malaria in the Chittagong Hill Tracts, Bangladesh

Bangladesh faces growing levels of Plasmodium falciparum resistance to chloroquine (CQ) and sulfadoxine–pyrimethamine (SP). Alternative antimalarial therapies, particularly combination regimens, need to be considered. Therefore, the efficacy of three antimalarial combination therapies was assessed in Chittagong Hill Tracts. A total of 364 P. falciparum patients were recruited and randomly assigned to either CQ+SP, mefloquine+artesunate (MQ+AS) or lumefantrine+artemether (Coartem©). Results showed that CQ+SP therapy was less effective than the two artemisinin-based combination therapies. The day 42 PCR-corrected efficacy rate was 62.4% for CQ+SP, 100% for MQ+AS and 97.1% for Coartem. Failures occurred at a shorter interval after CQ+SP treatment than after Coartem. The artemisinin-based therapies effectively prevented development of gametocytes, whereas CQ+SP did not. All three therapies were well tolerated, although reports of mild complaints during treatment appeared higher with MQ+AS. We conclude that CQ+SP is not a viable option for replacing CQ monotherapy as first-line P. falciparum treatment in this area of Bangladesh. A change to artemisinin-based combination therapy is recommended. Both Coartem and MQ+AS appear to be good options, effective in curing P. falciparum malaria and in preventing recrudescences following treatment.