Safety and Preliminary Efficacy of L-arginine in Severe Falciparum Malaria

Background: Mortality from severe malaria remains \~15% despite the use of the most rapidly parasiticidal antimalarial therapy, artesunate. Adjunctive treatments may improve outcome. Our overall goal is to determine if adjunctive treatment with L-arginine is safe and improves outcomes in severe malaria. In studies to date, we have shown that L-arginine is safe in moderately severe malaria, increases nitric oxide production and improves endothelial function. We now propose to extend these studies to patients with severe malaria. Aims: To determine the safety, preliminary efficacy, pharmacokinetics and pharmacodynamics of L-arginine infusion in severe malaria. Hypothesis: L-arginine will improve endothelial function, lactate clearance time and tissue oxygen delivery compared to saline with no clinically significant adverse effects. Methods: Based on previous pharmacokinetic modeling and simulations, we propose a phase 2A randomised controlled trial of L-arginine vs saline in severe malaria, each given over 8 hours. If safety is demonstrated this will be followed by a phase 2B open-label study of 24-hour infusion of L-arginine in severe malaria with safety and preliminary efficacy compared with the 8 hour infusions given in phase 2A. The primary outcomes will be the improvement in endothelial function and lactate clearance in patients given L-arginine infusion compared with those who received saline. Among the secondary outcomes will be safety and the effect of L-arginine vs saline on tissue oxygen delivery (NIRS). Data from both phase 2A and 2B will be used to generate a pharmacokinetic/ pharmacodynamic model.