Zotiraciclib hydrochloride is a novel small molecule multi-target enzyme inhibitor with activity in inhibiting tumor growth. Zotiraciclib hydrochloride exerts its anti-tumor effect by reducing the level of Myc through inhibiting cyclin-dependent kinase 9 ( CDK9 ). Zotiraciclib hydrochloride may be useful for inhibiting cancers that cross the blood-brain barrier. The high protein level of MCL-1 of Zotiraciclib hydrochloride is associated with survival, suggesting that it may serve as a prognostic factor and inhibitory target in further studies.