Systemic therapy for echinoderm microtubule-associated protein-like 4 anaplastic lymphoma kinase non-small cell lung cancer brain metastases

The fusion between echinoderm microtubule-associated protein-like 4 (EML4) and anaplastic lymphoma kinase (ALK) occurs in 4−5% of non-small cell lung cancer (NSCLC) patients (1). Crizotinib (Xalkori^®), the first approved small-molecule kinase inhibitor, has been proven to be effective in treatment of advanced ALK-positive NSCLC, increasing progression-free survival (PFS), response rates, and overall quality of life (2). Approximately 15% to 35% of ALK-positive NSCLC patients develop brain metastases, ultimately resulting in high mortality rates (3). Although crizotinib has been proven to show successful treatment of extracranial tumor sites, its intracranial effectiveness has yet to be studied extensively (4).