Used as a targeted therapy for the treatment of non-small cell lung cancer (NSCLC), particularly in patients with ALK (anaplastic lymphoma kinase) gene rearrangements. It functions as an ALK inhibitor, blocking the activity of the abnormal ALK fusion protein that drives cancer cell growth and proliferation. Alectinib hydrochloride is effective in both treatment-naïve patients and those who have progressed on prior ALK inhibitors. It has shown high central nervous system penetration, making it effective in controlling brain metastases, a common complication in ALK-positive NSCLC. Its favorable safety profile and once-daily dosing support long-term use in managing advanced disease.