Efficacy and Safety of High-dose Ivermectin for Reducing Malaria Transmission: A Dose Finding Study

In western Kenya the prevalence of malaria in \<5 year olds has fallen from 70% in 1997 to 40% in 2008, where it has now stagnated. Innovative approaches are needed to continue towards elimination. Ivermectin is a broad spectrum antiparasitic endectocide widely used for the control of onchocerciasis and lymphatic filariasis at a dose of 150-200 mcg/kg. Ivermectin at this dose has a potent, but short-lived effect for 6-11 days on mosquito survival, egg-laying, and parasite sporogony. Higher doses are needed to prolong its mosquitocidal effects. Previous studies have shown ivermectin is very well tolerated and safe even up to 2,000 mcg/kg. This dose finding study will evaluate the transmission blocking effect of high-dose ivermectin to define the optimal dose for future use of ivermectin in combination with artemisinin-based combination therapy (ACT) for mass drug administration (MDA). It explores a research question of global relevance. A prolonged transmission blocking effect of ivermectin could have substantial consequences for malaria control in the next decades. The results are expected to inform national malaria control programs in malaria endemic countries, to inform WHO guidelines, and to contribute to the regulatory process.