AZ13705339 hemihydrate is a hemihydrate form of AZ13705339, exhibiting high potency and selectivity as a PAK1 inhibitor, demonstrating IC50 values of 0.33 nM for PAK1 and 59 nM for pPAK1. It also shows strong binding affinities with Kd values of 0.28 nM for PAK1 and 0.32 nM for PAK2. This compound is utilized in cancer research.