LAUSR

Introduction: Immune checkpoint inhibitors (ICIs) are standard therapies in advanced NSCLC. Although genotype‐directed tyrosine kinase inhibitors represent the standard of care for subsets of oncogene‐driven NSCLC, patients may receive ICIs during their disease course. The impact of sequential ICI and tyrosine kinase inhibitor therapy on the risk of hepatotoxicity has not been described. Methods: Patients with advanced ALK receptor tyrosine kinase (ALK)‐driven, ROS1‐driven, or MET proto‐oncogene, receptor tyrosine kinase (MET)‐driven NSCLC treated with crizotinib, with or without preceding ICI therapy, were identified. The cumulative incidences of crizotinib‐associated grade 3 or higher increases in transaminase level (per the Common Terminology Criteria for Adverse Events, version 4.0) were compared. Results: We identified 453 patients who had NSCLC with an oncogenic alteration in ALK receptor tyrosine kinase gene (ALK), ROS1, or MET proto‐oncogene, receptor tyrosine kinase gene (MET) and were treated with crizotinib (11 with and 442 without prior ICI therapy). Among the 11 patients treated with an ICI followed by crizotinib, five (cumulative incidence 45.5% [95% confidence interval (CI): 14.9–72.2]) experienced development of a grade 3 or 4 increase in alanine transaminase level and four (cumulative incidence 36.4% [95% CI: 10.0–64.2]) experienced development of a grade 3 or 4 increase in aspartate transaminase level. In comparison, among the 442 patients who received crizotinib only, a grade 3 or 4 increase in alanine transaminase level occurred in 34 patients (cumulative incidence 8.1% [95% CI: 5.7–11.0, p < 0.0001]) and a grade 3 or 4 increase in aspartate transaminase level occurred in 14 (cumulative incidence 3.4% [95% CI: 1.9–5.5, p < 0.0001]). There were no grade 5 transaminitis events. All cases of hepatotoxicity after sequential ICI and crizotinib use were reversible and nonfatal, and no case met the Hy's law criteria. Conclusions: Sequential ICI and crizotinib treatment is associated with a significantly increased risk of hepatotoxicity. Careful consideration and monitoring for hepatotoxicity may be warranted in patients treated with crizotinib after ICI therapy.