The study will compare the efficacy and safety of entrectinib with crizotinib in participants with advanced or metastatic ROS1 non-small cell lung cancer (NSCLC). The participants will self-administer oral entrectinib or crizotinib as described in the protocol and local prescribing information. Treatments will continue until progressive disease, unacceptable toxicity, death, or withdrawal from the study, whichever occurs first.

Inclusion Criteria:

• Histologically or cytologically-confirmed diagnosis of advanced or recurrent (Stage IIIB/C not amenable for radical treatment) or metastatic (Stage IV) NSCLC that harbors a documented ROS1 gene rearrangement.
• No prior treatment with a ROS1 tyrosine kinase inhibitor, chemotherapy or other systemic therapy for advanced or recurrent (Stage IIIB/C not amenable for radical treatment) or metastatic (Stage IV) NSCLC
• Prior radiotherapy is allowed if more than 14 days have elapsed between the end of treatment and randomization
• Measurable systemic disease according to RECIST v1.1
• Participants with measurable and non-measurable CNS lesions per RECIST v1.1, including leptomeningeal carcinomatosis
• Life expectancy of at least 12 weeks
• Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2
• Adequate hematologic, renal, liver functions
• Participants must have recovered from effects of any major surgery or significant traumatic injury at least 28 days before the first dose of study treatment
• Ability to swallow entrectinib and crizotinib intact without chewing, crushing, or opening the capsules
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods with a failure rate of <1% per year during the treatment period and for up to 5 weeks after the last dose of entrectinib or for at least 90 days after the last dose of crizotinib
• For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm.

Exclusion Criteria:

• Prior treatment with a ROS1 tyrosine kinase inhibitor, chemotherapy or other systemic therapy for advanced or recurrent (Stage IIIB/C not amenable for radical treatment) or metastatic (Stage IV) NSCLC
• NCI-CTCAE v5.0 Grade 3 or higher toxicities due to any prior therapy (excluding alopecia, fatigue, nausea and lack of appetite), which have not shown improvement and are strictly considered to interfere with current study drug
• History of recent (within the past 3 months) symptomatic congestive heart failure or ejection fraction ≤ 50% observed during screening for the study
• History of prolonged corrected QTc interval
• Peripheral sensory neuropathy ≥ Grade 2
• Known interstitial lung disease, interstitial fibrosis, or history of tyrosine kinase inhibitor-induced pneumonitis
• Previous malignancy within the past 3 years
• Incomplete recovery from any surgery prior to the start of study treatment
• Active GI disease (e.g., Crohn's disease, ulcerative colitis or short gut syndrome) or other malabsorption syndrome that would reasonably impact drug absorption
• History of prior therapy-induced pneumonitis
• Any condition (in the past 3 months) e.g., myocardial infarction, unstable angina, coronary/peripheral artery bypass graft, cerebrovascular accident or transient ischemic attack, stroke, symptomatic bradycardia, or uncontrolled arrhythmias requiring medication
• Known active infections (bacterial, fungal or viral, including human immunodeficiency virus positive)
• History of hypersensitivity to any of the additives in the entrectinib and/or crizotinib drug formulations
• Pregnant or lactating women
• Known human immunodeficiency virus (HIV) positivity or acquired immunodeficiency syndrome (AIDS)-related illness
• 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.

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data\_sharing