Methods of treating malaria comprising administration of compounds of Formula (I') or a pharmaceutically acceptable salt thereof, to a subject in need thereof, wherein the variables are as defined herein. It also provides uses of the compounds of Formula (I), as defined herein, for inhibiting plasmepsin X, plasmepsin IX or plasmepsin X and IX activity, for treating a Plasmodium infection, and for treating malaria. Also provided are methods of treatment further comprising administration of one or more additional anti-malarial compounds.