Second-generation ALK-TKIs have different molecular profiles of drug resistance-associated genetic alterations after failure of second-line treatment for ALK fusion positive advanced NSCLC

Objective To compare and investigate the molecular profiles in acquired resistance-associated genetic alterations of second-generation anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs) in order to provide evidence for the management of ALK fusion positive advanced non-small cell lung cancer (NSCLC). Methods An observational study was conducted on 103 patients with ALK-fusion positive advanced NSCLC who received first-line treatment of crizotinib and then second-line treatment of second-generation ALK-TKIs in Zhongshan Hospital from 2014 to 2020. Genetic alteration profiles were analyzed by next generation sequencing (NGS) on tissue or liquid samples after relapse of second-generation ALK-TKIs. Results The acquired ALK-TKIs-resistant genetic alterations were dominated by ALK kinase domain mutations (66.7%), which had a significant higher incidence in V3 variant compared with V1 variant (85.7% vs 55.6%, P=0.003 9). The most common ALK mutations were G1202R/K and L1196M, and the former was more common in V3 subtype (57.1% vs 4.4%, P < 0.000 1) while the latter in V1 subtype (31.1% vs 14.3%, P=0.079 4). The patients who were resistant to alectinib had the highest incidence of secondary mutations, with G1202R (31.6%) and G1269A (12.3%) were the top 2 mutations. G1202R, L1196M, F1174X and C1156Y were more common in the patients resistant to ceritinib. F1174X, D1203N and E1210K were the top 3 mutations among the patients who progressed after brigatinib therapy. D1203N (0 vs 6.7% vs 20%, P=0.000 2) and E1210K (1.8% vs 0 vs 15.0%, P=0.003 5) mainly occurred in the brigatinib group. The sequential application of ALK TKIs may cause co-mutations of ALK gene. Conclusion The profile of genetic alteration failed from second-line second-generation ALK-TKIs treatment are complex and diverse. There are differences between different drugs and different ALK variants, as well as compound mutations, which increase the difficulty in later line therapy. Therefore, the clinical treatment decisions of advanced NSCLCs with ALK positive should be established on the fully consideration of the drug resistance mechanism.