Inclusion Criteria:

• Stage IIIB/IV NSCLC non eligible to locoregional treatment with curative intent
• ALK rearrangement confirmed by IHC and/or FISH or NGS according to local methods
• Patient included in the EXPLORE ALK study
• Age > or = 18 years
• Patient treated with first-line new generation ALKi
• Patient agrees to sign an informed consent form and to collect blood samples at inclusion, first tumor evaluation and progression and for whom tumor biopsy at diagnosis is available
• Patient enrolled in the french National Health Insurance program or with a third- party payer

Exclusion Criteria:

• Patients who do not wish to participate in Bioexalk
• Patients under guardianship