Study to Assess the Incidence of Hemolysis, Safety, and Efficacy of Tafenoquine (SB-252263, WR238605) Versus Primaquine in Subjects With Plasmodium Vivax Malaria

This is a prospective, double-blind, double-dummy, multicenter, comparative study. A total of 300 subjects will be randomized to treatment on Day 1, of which a minimum of 50 female subjects must be enrolled that display moderate glucose-6-phosphate dehydrogenase (G6PD) deficiency (\>=40% - \<70% of the site median G6PD value). Subjects must have a blood smear that is positive for P. vivax at entry. Subjects will be randomized 2:1 to receive tafenoquine (TQ)/chloroquine(CQ) or the active comparator primaquine (PQ)/CQ. All subjects will receive CQ on Days 1 to 3, followed by TQ or PQ and matching placebo beginning on Day 1 or 2. Tafenoquine, or matching placebo, will be given as a single, 300mg dose. Subjects will receive PQ (15mg once daily) or matching placebo for 14 days. The duration of the study is 180 days, including screening and randomization to treatment (Day 1), three in-hospital days (Days 1-3), four out-patient visits while on treatment with study medication (Days 5, 8, 11 and 15) and seven follow-up visits (Days 22, 29, 60, 90, 120, 150 and 180). The primary safety data collected in this study will help to understand the hemolysis risk to both G6PD-normal and G6PD-deficient subjects. The efficacy data produced from this study will support the results for sister study TAF112582, the pivotal phase III efficacy and safety study of the TQ program.