CNS Metastases in Patients With MET Exon 14–Altered Lung Cancers and Outcomes With Crizotinib

PURPOSE Although MET exon 14 ( METex14)–altered lung cancers were first identified more than a decade and a half ago, the frequency of CNS metastatic disease remains poorly defined. Furthermore, the seminal trial of crizotinib in these patients (PROFILE 1001) did not report patterns of CNS response or progression. PATIENTS AND METHODS Patients with pathologically confirmed, advanced non–small-cell lung cancers (NSCLC) harboring a METex14 alteration by targeted DNA/RNA sequencing were studied. The incidence of brain metastases and the outcomes of MET inhibition with crizotinib were analyzed. RESULTS Eighty-three patients with METex14-altered metastatic NSCLC were identified. The incidence of CNS metastases at diagnosis was 17% (95% CI, 10% to 27%). The lifetime incidence was 36% (95% CI, 26% to 47%); 83% of patients had parenchymal disease, and 17% had leptomeningeal disease. The probability of having brain metastasis at 1, 2, and 3 years was 24%, 35%, and 38%, respectively. Fifty-four patients received crizotinib. The median time to radiologic CNS progression was 5.8 months (range, 3.7-20.0 months). Patterns of crizotinib progression were as follows: intracranial only in 10% of patients, intracranial and extracranial in 12%, and extracranial only in 78%. In patients with brain metastases before treatment, the median time on crizotinib was 7.5 months (range, 7.2-11.7 months). CONCLUSION CNS metastases, including leptomeningeal disease, occurred in more than a third of patients with METex14-altered lung cancers. In crizotinib-treated patients with or without CNS metastases, CNS failure was seen in less than a quarter of patients on progression.