Cumulative incidence rates for CNS and non-CNS progression in two phase II studies of alectinib in ALK-positive NSCLC.

Background: We evaluated the cumulative incidence rate (CIR) of central nervous system (CNS) and non-CNS progression in alectinib-treated patients with anaplastic lymphoma kinase (ALK)-positive non-small-cell lung cancer (NSCLC) to determine the extent to which alectinib may treat or control CNS disease.

Methods: Patients with crizotinib-pretreated locally advanced or metastatic disease received alectinib 600 mg orally twice daily in two phase II trials. All patients underwent baseline imaging and regular centrally reviewed scans.

Results: At 24 months, the CIR for CNS progression was lower in patients without vs with baseline CNS metastases (8.0 vs 43.9%). Patients with baseline CNS disease and prior radiotherapy had a higher CIR of CNS progression than radiotherapy-naive patients (50.5 vs 27.4%) and a lower CIR of non-CNS progression (25.8 vs 42.5%). Adverse events leading to withdrawal occurred in 5.9% and 6.7% of patients with and without baseline CNS metastases, respectively.

Conclusions: This analysis indicates a potential role for alectinib in controlling and preventing CNS metastases.