AZ13705339 hemihydrate is a highly potent and selective PAK1 inhibitor with IC50s of 0.33 nM and 59 nM for PAK1 and pPAK1, respectively. AZ13705339 hemihydrate has binding affinities to PAK1 and PAK2, with Kds of 0.28 nM and 0.32 nM, respectively. AZ13705339 hemihydrate can be used in the research of cancers[1].