Clinical utility of tafenoquine in the prevention of relapse of Plasmodium vivax malaria: a review on the mode of action and emerging trial data

Abstract

Clinical utility of tafenoquine in the prevention of relapse of Plasmodium vivax malaria: a review on the mode of action and emerging trial data Aurore B Hounkpatin,1–3,* Andrea Kreidenweiss,1,2,* Jana Held1–3 1Institute of Tropical Medicine, Eberhard Karls University Tübingen, Tübingen, Germany; 2German Centre for Infection Research, Partner Site Tübingen, Tübingen, Germany; 3Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon *These authors contributed equally to this work Abstract: Tafenoquine is an 8-aminoquinoline with activity against all human life cycle stages of Plasmodium vivax, including dormant liver stages – so called hypnozoites. Its long half-life of ~15 days is allowing for a single exposure regimen. It has been under development since 1980 and received approval by the US Food and Drug Administration in summer 2018 as an anti-relapse drug for P. vivax malaria in patients aged 16 years and older and for prophylaxis of malaria caused by any Plasmodium species in adults. Prior to tafenoquine administration, glucose-6-phosphate dehydrogenase (G6PD) deficiency needs to be excluded by testing. Individuals with a deficient G6PD activity are at risk of tafenoquine-induced hemolysis – as is the case for primaquine, the mainstay drug for P. vivax radical cure. A wealth of clinical studies have been conducted and are still ongoing to assess the safety, tolerability, and efficacy of tafenoquine. This review focuses on data emerging from the latest clinical trials on P. vivax radical cure with tafenoquine, the key studies for regulatory approval of tafenoquine, and elucidates the latest hypothesis on the mode of action. Keywords: hypnozoite, 8-aminoquinoline, WR238605, radical cure