Inclusion Criteria:

          -  Participants with histologically or cytologically confirmed locally advanced or
             metastatic NSCLC (Stage IIIB or IV accordingly to American Joint Committee on Cancer
             [AJCC] classification)

          -  Life expectancy of at least 12 weeks, in the opinion of the Investigator

          -  Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≤ 2

          -  Having contributive biopsy performed on fresh tissue (FFPE blocks required) taken
             after progression on previous therapy showing presence of anaplastic lymphoma kinase
             (ALK) rearrangement, assessed by immunohistochemistry (IHC) and confirmed by
             fluorescence in situ hybridization (FISH)

          -  Absence of resistance mechanism to alectinib assessed by the Biomarkers Board

          -  Disease progression, limited to central nervous system (CNS) without possibility of
             tissue biopsy

          -  Non-contributive molecular analyses (not enough tumor cells or deoxyribonucleic acid,
             [DNA] amount or failure of analyses for technical reasons): inclusion is at
             investigator discretion (decision made upon Biomarker Board recommendation)

          -  History of crizotinib exposure

          -  Washout period: if previous progression on crizotinib: 7 days from last intake of the
             drug

          -  If previous progression on chemotherapy: 28 days

          -  If previous radiation therapy: 15 days

          -  Participants must have recovered from treatment toxicities to ≤ Grade 1 or to their
             pretreatment levels (for participants who have developed interstitial lung disease
             [ILD], they must have fully recovered)

          -  Recovery from effects of any major surgery, or significant traumatic injury, at least
             35 days before the first dose of alectinib

          -  Adequate hematologic function

          -  Adequate renal function

          -  For all females of childbearing potential, a negative pregnancy test must be obtained
             within three days before starting study drug

          -  For women who are not postmenopausal (≥ 12 months of non-therapy-induced amenorrhea)
             or surgically sterile (absence of ovaries and/or uterus): agreement to remain
             abstinent or use two adequate methods of contraception, including at least one method
             with a failure rate of < 1% per year, during the treatment period and for at least 90
             days after the last dose of study drug

          -  For men: agreement to remain abstinent or use a barrier method of contraception (e.g.,
             condom) during the treatment period and for at least 90 days after the last dose of
             study drug and agreement to refrain from donating sperm during this same period

          -  Participant has national health insurance coverage

        Exclusion Criteria:

          -  Prior therapy with other ALK inhibitors than crizotinib (including alectinib)

          -  Participants with symptomatic CNS metastases who are neurologically unstable or
             require increasing doses of steroids within one week prior to Day 0 to manage CNS
             symptoms

          -  Participants with progression limited to CNS and eligible to a focal treatment
             (surgery or stereotaxic radiotherapy)

          -  Administration of strong/ potent cytochrome P450 3A (CYP3A) inhibitors or inducers, or
             agents with potential QT prolonging effects within 14 days prior to first
             administration of study drug

          -  Liver disease

          -  Any clinically significant concomitant disease or condition that could interfere with,
             or for which the treatment might interfere with, the conduct of the study or the
             absorption of oral medications or that would, in the opinion of the investigator, pose
             an unacceptable risk to the participant in this study

          -  Active or uncontrolled infectious diseases requiring treatment

          -  History of organ transplant

          -  Participants with baseline QTc > 470 ms or participants with symptomatic bradycardia

          -  Pregnant or lactating women

          -  History of hypersensitivity to any of the additives in the alectinib drug

          -  Any psychological, familial, sociological, or geographical condition potentially
             hampering compliance with the study protocol requirements and/or follow-up procedures;
             those conditions should be discussed with the participant before trial entry

          -  Serious, uncontrolled infections or current known infection with human
             immunodeficiency virus (HIV).