This is an open-label, multicenter, single-arm, expanded access study designed to provide alectinib to participants with ALK-rearranged NSCLC after disease progression on or intolerance to prior ALK tyrosine kinase inhibitor (TKI) therapy. Participants will receive alectinib until disease progression, unacceptable toxicity, withdrawal of consent, patient or physician decision to discontinue treatment, death, alectinib becomes commercially available in the United States following approval of alectinib by the FDA, or the Sponsor decides to close the trial, whichever occurs first (approximately 15 months).

Inclusion Criteria:

• Participants with locally advanced (American Joint Committee on Cancer [AJCC] Stage IIIB) not amenable to curative therapy or metastatic (AJCC Stage IV) NSCLC
• Life expectancy of at least 12 weeks
• Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-3
• Histologically confirmed NSCLC
• Documented ALK rearrangement as assessed by approved fluorescence in situ hybridization (FISH) test, using the Vysis ALK Break Apart FISH Probe Kit or the Ventana immunohistochemistry (IHC) test
• After disease progression on or intolerance to prior ALK TKI therapy: 1) participants need to have a minimum washout period of at least 5 half-lives between the last dose of ALK TKI therapy or other targeted therapies and the first dose of study treatment; 2) participants must have recovered from treatment toxicities to less than or equal to (</=) Grade 1 or to their pretreatment levels (for participants who have developed interstitial lung disease [ILD], they must have fully recovered); 3) participants can either be chemotherapy-naïve or have received at least one line of platinum-based chemotherapy for locally advanced or metastatic disease
• Recovery from effects of any major surgery or significant traumatic injury at least 28 days before the first dose of study treatment
• Adequate hematological and renal function
• Agreement to use highly effective methods of contraception per protocol definitions

Exclusion Criteria:

• Prior therapy with alectinib
• Participants with symptomatic central nervous system (CNS) metastases who are neurologically unstable or require increasing doses of steroids within 1 week prior to Day 1 to manage CNS symptoms
• 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
• Participants with liver disease
• Any clinically significant concomitant disease or condition that could interfere with the conduct of the study
• Active or uncontrolled infectious diseases requiring treatment
• History of organ transplant
• Participants with baseline QTc > 470 milliseconds (ms) or participants with symptomatic bradycardia
• Pregnant or lactating, or intending to become pregnant during the study
• History of hypersensitivity to any of the additives in alectinib formulation
• 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 participants before trial entry
• Serious, uncontrolled infections or current known infection with human immunodeficiency virus (HIV)