The main purpose of the study is to evaluate safety and efficacy of X-396(Ensartinib) capsule in patients with ALK-positive non-small cell lung cancer previously treated with crizotinib.While exploring the relationship between biomarkers and drug efficacy and safety.

This is a phase II, multicenter, single-arm study in which the safety and efficacy of X-396(Ensartinib) will be assessed in adult Chinese patients with ALK-positive(rearrangement) non-small cell lung cancer previously treated with crizotinib. Approximately 144 patients with locally advanced or metastatic NSCLC which carry ALK -rearrangement will be enrolled in the study.

Inclusion Criteria:

• Histologically or cytologically confirmed diagnosis of metastatic non-small cell lung cancer.
• Evidence of positive ALK.
• Patients must have demonstrated progression during or after crizotinib treatment.
• Age 18 years or older at the time of informed consent.
• Eastern cooperative oncology group performance status (ECOG PS) of 0-2
• Measurable disease by response evaluation criteria in solid tumors (RECIST) version 1.1 (v1.1).
• Asymptomatic CNS metastases do not require the use of steroids or anticonvulsants.
• Willingness and ability to comply with the trial and follow-up procedures.
• Ability to understand the nature of this trial and give written informed consent.

Exclusion Criteria:

• Prior use of ALK TKIs with the exception of crizotinib.
• Patients currently receiving cancer system therapy.
• Use of an investigational drug within 4 weeks prior to the first dose of study drug.
• Presence of active gastrointestinal (GI) disease or other condition that will interfere significantly with the absorption, distribution, metabolism, or excretion of study medications.
• Patients with a known allergy or delayed hypersensitivity reaction to drugs.