Artemisinin resistant Plasmodium falciparum has emerged in the countries of the Greater Mekong sub-region posing a serious threat to global malaria elimination efforts. Annual incidence rate of malaria in Viet Nam has reduced more than 90% in the past 20 years. One of most vital factors is using artemisinin combination therapy in the national malaria control program. Unfortunately, artemisinin resistance due to the mutations on K13 gene of falciparum parasites that has expanded from western Cambodia to several countries in the region since 2009, has threaten the success of the Malaria Control/Elimination Program. Monitoring studies on the susceptibility of ACTs, especially DP, have also been conducted in Vietnam and the results revealed a rapid decline in the susceptibility of Plasmodium falciparum to dihydroartemisinin–piperaquine in the south of Vietnam and that resulted from both resistance to artemisinin and piperaquine. In 2017 the treatment failure rate of those Pf cases increased to 50%.
Several studies have been conducted to identify the best antimalarial drug(s) for acute falciparum malaria cases including new antimalarial drugs as cipargamin (KAE 609), KAF 156, and artefenomel (OZ 439), but these are in phase II of development and will likely not reach the market until 2025. So far a triple artemisinin combination TACT: Dihydroartemisinin – pepiperaquine – mefloquine had the best cure rate (100%) in Vietnam. The result could be used as a short-term solution while waiting other available new drugs or new combinations.