Uncomplicated Malaria

Plasmodium vivax is the most geographically widespread malaria species and the second largest contributor to symptomatic malaria worldwide. It accounts for half of all malaria cases outside Africa, with an estimated 14.3 million clinical vivax malaria cases reported annually, contributing to an annual cost of US$359 million. Children are most vulnerable to infection, with P. vivax prevalence peaking between 2 to 6 years of age. In Papua New Guinea (PNG), there are \>1.5 million suspected P. vivax cases annually, and while P. falciparum infections are the most prevalent, P. vivax transmission is the most intense in the world. P. vivax in PNG provides a unique epidemiological setting in which to assess innovative treatments in children.The complex biology of P. vivax represents a challenge for malaria control and chemotherapy, especially dormant liver-stage parasites (hypnozoites) which can reactivate (relapse) and cause disease at a time remote from the primary infection. Hypnozoite relapse is the primary cause of vivax malaria in endemic regions and is resistant to most antimalarial drugs. Identifying effective treatments for radical cure, the complete elimination of parasites (both blood- and liver-stage), is therefore a priority. The World Health Organization (WHO) recommends a 14-day radical cure regimen for uncomplicated vivax malaria; comprised of blood stage treatment (chloroquine or artemisinin combination therapy (ACT)) and 14 days of the 8-aminoquinoline drug primaquine (PQ; 0.25-0.5 mg/kg/day) for liver-stage cure. More recently, the 8-aminoquinoline tafenoquine has garnered interest as an alternative radical cure agent to primaquine. However, there is limited data on the pharmacokinetics, tolerability and radical cure efficacy of tafenoquine in children. Furthermore, early data suggest a drug interaction between TQ and artemisinin combination therapy (ACT) drugs - which requires further investigation and confirmation. This study will generate critical paediatric safety, tolerability, pharmacokinetic, and preliminary efficacy data for TQ when administered with either artemether-lumefantrine or dihydroartemisinin-piperaquine in PNG children with uncomplicated malaria.

Malaria is caused by protozoan parasites of the genus Plasmodium and it is the most important parasitic disease in terms of mortality and morbidity. Estimates of 247 million malaria cases and 619.000 deaths worldwide were reported by WHO for the year 2021 (1). Plasmodium falciparum can lead to severe malaria and accounts for 90% of malaria deaths that mainly occur in children below the age of 5 years in Sub-Saharan Africa. A simplified treatment regimen, ideally a single-day cure (or at most 2-day dosing regimen), of uncomplicated malaria due to P. falciparum would be the magic in the antimalarial armamentarium. Improving treatment adherence is one of the key factors in reducing mortality and morbidity and also the transmission of malaria, and such a regimen would substantially increase adherence. To find a new non-artemisinin combination therapy with a shorter regimen, ideally, a single-dose cure, with low resistance potential would be the aim. The two compounds tested here are ZY19489, a triaminopyrimidine, and ferroquine (FQ), a next-generation 4-aminoquinoline. Both compounds show unique features in terms of long half-life, and activity against current drug-resistant strains. Therefore, the main goal of this clinical trial is to assess the safety of the ZY19489-FQ combination given as a 1- or 2-day dose regimen.