FRAX597 is determined to be a potent, ATP-competitive inhibitor of group I PAKs (PAK 1-3), with biochemical IC50 values as follows: PAK1 IC50=8 nM, PAK2 IC50=13 nM, PAK3 IC50=19 nM. The IC50 toward PAK4, a member of group II PAKs is >10 μM. At a concentration of 100 nM FRAX597 displays a significant (>80% inhibition) inhibitory capacity toward YES1 (87%), RET (82%), CSF1R (91%), TEK (87%), PAK1 (82%), and PAK2 (93%). When measured using the Kinase Glo Assay in the presence of 20 nM protein and 1 μM ATP, FRAX597 displayed an IC50 value of 48 nM against wild type PAK1, while IC50 values against the V342F and V342Y PAK1 mutants are higher than 3 μM and 2 μM, respectively.