Randomisation and masking
Eligible patients were randomly assigned in a 1:1:1 ratio to dihydroartemisinin–piperaquine alone, dihydroartemisinin–piperaquine plus tafenoquine, or dihydroartemisinin–piperaquine plus primaquine. All patients received open-label dihydroartemisinin–piperaquine for 3 days plus masked treatment as follows: tafenoquine 300-mg single dose on day 1 and placebo for primaquine on days 1–14; primaquine 15 mg on days 1–14 and placebo for tafenoquine on day 1; or placebo for tafenoquine on day 1 and placebo for primaquine on days 1–14. The study sponsor provided a computer-generated randomisation schedule to the site. Visually matched tafenoquine and primaquine placebos were used to maintain masking of site staff, patients, and sponsor personnel.As methaemoglobin increases are associated with use of 8-aminoquinolines such as primaquine and tafenoquine, methaemoglobin assessments were done by an independent site assessor to avoid unmasking. Additionally, independent sponsor staff processed the methaemoglobin data. The independent methaemoglobin site and sponsor staff did not have access to other study data.