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