Alectinib is a highly selective, potent tyrosine kinase inhibitor that targets anaplastic lymphoma kinase (ALK) and RET. It works by inhibiting ALK phosphorylation and the subsequent activation of downstream signaling proteins like STAT3 and AKT. This action decreases the viability of tumor cells harboring ALK fusions, amplifications, or activating mutations. Alectinib and its major active metabolite, M4, are active against multiple mutant forms of the ALK enzyme, including those responsible for resistance to first-generation ALK inhibitors like crizotinib.

Alectinib is indicated for the treatment of patients with anaplastic lymphoma kinase (ALK)-positive, metastatic non-small cell lung cancer (NSCLC). It is also used to prevent NSCLC from returning after surgery to remove the tumor. In preclinical studies, alectinib demonstrated antitumor activity and prolonged survival in mouse models, including those with intracranial ALK-driven tumors. It is administered as an oral capsule and is a second-generation ALK inhibitor that offers improved efficacy and central nervous system penetration compared to earlier therapies.