Antimalarial efficacy monitoring after nearly 20 years of artemisinin-based combination therapy in Africa: recalibrating guidance.

Timely identification of resistance to antimalarials is necessary to ensure effective malaria case management. The backbone of antimalarial resistance surveillance strategies is the therapeutic efficacy study (TES). Originally designed to be easily deployable, in recent years, TES have become increasingly complex and slow to yield results. Concurrently, advances in molecular surveillance techniques, the emergence and spread of artemisinin partial resistance in Africa, and advances in antimalarial drug stewardship through multiple first-line therapies have changed the context in which TES are implemented. In this opinion article, we outline considerations for recalibrating TES methodology. More efficient TES, coupled with molecular surveillance, could provide timely and actionable data for malaria-endemic countries as they manage treatment policies in the context of drug resistance in Africa.