Factors Associated with Disease Progression after Discontinuation of Immune Checkpoint Inhibitors for Immune-Related Toxicity in Patients with Advanced Non–Small Cell Lung Cancer

PURPOSE: Among patients with advanced non-small cell lung cancer (NSCLC) who discontinue immune checkpoint inhibitors (ICI) because of immune-related adverse events (irAE), post-discontinuation clinical outcomes and factors associated with disease progression after discontinuation are largely unknown. EXPERIMENTAL DESIGN: Clinicopathologic data were abstracted from patients with advanced NSCLC who received ICI and discontinued treatment because of irAE. Factors associated with post-discontinuation progression-free survival (PFS) and post-discontinuation overall survival (OS) were evaluated. RESULTS: Of 2,794 patients, 10% (N = 271) discontinued ICI because of irAE, and the median duration of ICI treatment before discontinuation for irAE was 5.9 months (range, 0.03-73.5). A longer treatment duration before discontinuation for irAE was associated with improved post-discontinuation outcomes: for patients on ICI for <3 months (N = 89), 3 to 6 months (N = 49), and >6 months (N = 133) before discontinuing for irAE, the median post-discontinuation PFS was 6.2, 13.9, and 25.8 months (P < 0.001), respectively, and the median post-discontinuation OS was 21.7, 42.7, and 86.9 months (P < 0.001), respectively. At multivariable analyses, predictors of longer post-discontinuation PFS were PD-L1 ≥ 50%, complete response/partial response (CR/PR) to treatment, and treatment duration before discontinuation between 3 to 6 months and >6 months; predictors of longer post-discontinuation OS were nonsquamous histology, CR/PR, and treatment duration before discontinuation >6 months. The use of immunosuppressive agents for toxicity management did not affect post-discontinuation outcomes. CONCLUSIONS: A longer treatment duration before discontinuation, a best objective response of CR/PR, PD-L1 ≥50%, and nonsquamous histology may help clinicians identify patients who may experience long-term disease control after discontinuation of ICI for irAE.