A Study to Evaluate the Pharmacokinetics of a Single Dose of Tafenoquine Co-administered With Either Artemether + Lumefantrine or Dihydroartemisinin + Piperaquine Tetraphosphate

This will be a single-centre, 5-cohort, randomized open-label, parallel-group study in healthy volunteer subjects. This study aims to provide sufficient pharmacokinetic (PK) evidence to support the safe usage of Tafenoquine (TQ) in studies and markets where the Artemisinin-based Combination Therapies (ACTs) are the standard of care for patients with Plasmodium vivax malaria (i.e., co administration with TQ). The objective of this study is to assess the pharmacokinetics, safety and tolerability of TQ when co-administered with the chosen ACTs (AL and DHA + PQP), administered concomitantly in healthy subjects. Specifically, the study will evaluate whether there are drug-drug interactions between TQ and each of the ACTs and if these interactions are considered to be clinically significant. The co-primary objectives of this study are to characterize both the effects of a 300 milligram (mg) single dose of TQ on the pharmacokinetics; changes in (area under the concentration-time curve from 0 to time t) AUC (0-t), AUC (0-infinity), and maximum observed concentration (Cmax) of each of the two Artemisinin-based Combination Therapies (ACT) according to their prescribed dose when co-administered as well as the effects of the ACTs on the PK of TQ. A total of 120 subjects (24 subjects in each of 5 cohorts) are planned to be enrolled in order to ensure a target sample size of at least 22 subjects completing the study per cohort. All subjects will arrive in the unit at least 24 hours prior to dosing and be discharged after 72-hour post first dose assessments have been completed. Subjects will return for outpatient visits on Days 7, 14, 21, 28, and 56 after first dose.