Introduction: Approximately 5% of all diagnosed non-small cell lung cancer (NSCLC) patients harbor a genetic rearrangement between the ALK and EML4 genes, representing a specific molecular, histological and clinical subgroup (ALK+ NSCLC). To date, upfront treatment with ALK-tyrosine-kinase inhibitors (ALK-TKIs) has replaced chemotherapy in the first line setting for this subset of patients with excellent results. However, all treated patients eventually develop acquired resistance mechanisms to these agents (mainly resistance mutations) and experience progression of the disease.Areas covered: This paper provides a comprehensive state-of-the-art review about first-line approved ALK-TKIs, furthermore, it discusses the most promising ALK-TKIs under development designed to overcome resistance mutations and their implications.Expert opinion: Alectinib should currently be regarded as the standard of care for the first-line treatment of ALK+ NSCLC, considering its superior efficacy and safety profile. Regarding developing agents, lorlatinib and ensartinib appear to be the most promising ones, even though the data from their trials are still immature.
Keywords: ALK; ALK-TKI; EML4; EML4-ALK RTK; G1202R; NSCLC; first-line treatment; resistance mechanisms.