Casein Kinase inhibitor A86 is a potent and orally active casein kinase 1α (CK1α) inhibitor. Casein Kinase inhibitor A86 also inhibits of CDK7 (TFIIH) and CDK9 (P-TEFb). Casein Kinase inhibitor A861 induces leukemia cell apoptosis, and has potent anti-leukemic activities.