Background and rationale of the eXalt3 trial investigating X-396 in the treatment of ALK+ non-small-cell lung cancer

Despite significant advancements in the treatment of anaplastic lymphoma kinase (ALK) positive non-small-cell lung cancer (NSCLC) since the advent of crizotinib, the development of acquired resistance and poor CNS efficacy have necessitated the search for novel and more robust therapies. Ensartinib (X-396) is a novel second-generation ALK-tyrosine kinase inhibitor (TKI) that holds much clinical promise. Preclinical data have demonstrated increased potency of the drug as compared with crizotinib and other second-generation ALK-TKI therapies such as alectinib and ceritinib. This review highlights the first- A nd second-generation ALK inhibitors approved for the treatment of ALK-positive NSCLC and discusses the clinical trial protocol for the eXalt3 trial (NCT02767804) comparing the efficacy and safety of ensartinib to crizotinib in patients diagnosed with ALK-positive NSCLC who are naive to prior ALK-TKI treatment.