CP681301 is a potent CDK5 inhibitor. CP681301 shows antiproliferative activity. CP681301 decreases the expression of CD133, OLIG2, SOX2, KI67, pCDK5 protein level in GSCs (Glioma stem cells). CP681301 reduces self-renewal in mouse glioma xenografts. CP681301 shows anti-tumor activity in Drosophila.