KF-20444 is an orally active ALK inhibitor with the ability to penetrate the blood-brain barrier. It exhibits potent inhibitory effects on ALK fusion proteins (EML4-ALK) and ALK-resistant mutations, including L1196M, G1202R, and F1174L. KF-20444 effectively suppresses the phosphorylation of ALK in cancer cell lines driven by ALK, thereby inhibiting cancer cell proliferation and inducing apoptosis (apoptosis). In mouse models bearing ALK-positive non-small cell lung cancer or neuroblastoma, it demonstrates antitumor efficacy. KF-20444 is applicable for research into ALK-driven malignancies.