Introduction: The programmed death 1 antibodies (PD-1 Ab) nivolumab and pembrolizumab improve overall survival (OS) in advanced non-small-cell lung cancer (NSCLC). We evaluated the correlation between immune-related adverse events (irAE) and treatment interruption due to irAE on clinical efficacy of PD-1 Ab in advanced NSCLC.
Patients and methods: Advanced NSCLC patients treated with PD-1 Ab between June 2015 to November 2017 at BC Cancer were identified. Demographic, tumor, treatment details, and frequency and grade (Common Terminology Criteria for Adverse Events, version 4.0) of irAE were abstracted from chart review. Kaplan-Meier curves of OS from initiation of PD-1 Ab were generated. Multivariable analysis with 6- and 12-week landmark analysis was performed by Cox proportional hazard regression models.
Results: In a cohort of 271 patients, irAEs were observed in 116 patients (42.8%). Nivolumab recipients developing colitis had lower OS compared to those who did not at the 6-week landmark (P = .010) and 12-week landmark (P = .072). For the entire cohort, 56 patients (20.7%) needed treatment interruption because of an irAE. Treatment interruption correlated with lower OS at the 6-week landmark (P = .005) and 12-week landmark (P = .008). Six-week landmark multivariable analysis identified Charlson Comorbidity Index score of 3 or higher, Eastern Cooperative Oncology Group Performance Status of 2 or higher, presence of liver metastases, and irAE greater than grade 2 versus no irAE to be associated with decreased OS (each P < .05).
Conclusion: Treatment interruption due to irAE was associated with a lower median OS compared to continuous PD-1 Ab therapy. Shorter OS seen with severe irAE might reflect the need for improved physician education in irAE treatment algorithms.
Keywords: Immune related adverse events; Immunotherapy; Real world data.
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