ALK TKIs, particularly second- and third-generation ALK TKIs, have significantly improved progression-free survival (PFS) in patients with advanced ALK-positive non-small cell lung cancer (NSCLC). However, patients continue to face challenges related to drug resistance and disease progression; in the CROWN study, 40% of patients still experienced disease progression within five years. There are currently no standard treatment recommendations for this patient population. This study retrospectively evaluated the efficacy and safety of ensartinib combined with anlotinib as a second-line treatment in patients who had developed resistance to lorlatinib. The inclusion criteria for data collection were patients aged ≥18 years with histologically confirmed stage IIIB-IV ALK-positive NSCLC who had developed resistance to lorlatinib; prior to lorlatinib treatment, patients could have received up to two other ALK-TKIs, excluding ensartinib.

Co-hort 1: Strict co-hort Inclusion criteria1：Histologically or cytologically confirmed stage IIIB-IV non-small cell lung cancer; Inclusion criteria2：Age ≥ 18 years at the time of signing the informed consent form; Inclusion criteria3：ALK-positive status confirmed by tissue samples or blood tests at each centre; Inclusion criteria4：History of resistance to lorlatinib treatment; prior use of ensartinib is not permitted; patients must have received a maximum of two other ALK-TKIs; prior receipt of ≤2 courses of chemotherapy is permitted; ECOG Performance Status (PS) score between 0 and 2, with no deterioration within 2 weeks prior to study entry;

Co-hort 2 (Compassionate Use Cohort):

Inclusion criteria1： Resistance to lorlatinib treatment; Inclusion criteria2： No restrictions on prior use of ensartinib or the number of prior lines of other ALK-TKIs and chemotherapy; Inclusion criteria3：Subjects with concomitant leptomeningeal metastases may be enrolled. For patients with leptomeningeal metastases (LM), diagnosis must be based on the three criteria outlined in the EANO-ESMO guidelines: clinical presentation, cranial imaging, and cerebrospinal fluid cytology. Tissue samples must not be derived from tumour sites that have previously undergone radiotherapy; however, new lesions arising after local treatment may be included; Inclusion criteria4：ECOG performance status of 0-4; Inclusion criteria5： Adequate organ system function, as determined by the investigator; Inclusion criteria6：All other inclusion criteria are consistent with items 1, 2 and 3 of Cohort 1.

Exclusion criteria1：Concurrent malignant tumours. Exclusion criteria2：Patients with leptomeningeal metastases (LM) who are unable to undergo contrast-enhanced MRI.

Exclusion criteria3：Patients who have undergone surgery within 4 weeks prior to treatment with the study drug, except for minor procedures deemed by the investigator not to preclude participation in the trial; or patients scheduled to undergo major surgery during the study period.

Exclusion criteria4：Patients who have experienced a marked deterioration in symptoms or signs within 2 weeks prior to screening and are deemed by the investigator to be unsuitable for participation in the trial.