Immune-related adverse events are associated with improved response, progression-free survival, and overall survival for patients with head and neck cancer receiving immune checkpoint inhibitors

Background: The authors hypothesized that patients developing immune-related adverse events (irAEs) while receiving immune checkpoint inhibition (ICI) for recurrent/metastatic head and neck cancer (HNC) would have improved oncologic outcomes. Methods: Patients with recurrent/metastatic HNC received ICI at 2 centers. Univariate and multivariate logistic regression, Kaplan-Meier methods, and Cox proportional hazards regression were used to associate the irAE status with the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) in cohort 1 (n = 108). These outcomes were also analyzed in an independent cohort of patients receiving ICI (cohort 2; 47 evaluable for irAEs). Results: The median follow-up was 8.4 months for patients treated in cohort 1. Sixty irAEs occurred in 49 of 108 patients with 5 grade 3 or higher irAEs (10.2%). ORR was higher for irAE+ patients (30.6%) in comparison with irAE− patients (12.3%; P =.02). The median PFS was 6.9 months for irAE+ patients and 2.1 months for irAE− patients (P =.0004), and the median OS was 12.5 and 6.8 months, respectively (P =.007). Experiencing 1 or more irAEs remained associated with ORR (P =.03), PFS (P =.003), and OS (P =.004) in multivariate analyses. The association between development of irAEs and prolonged OS persisted in a 22-week landmark analysis (P =.049). The association between development of irAEs and favorable outcomes was verified in cohort 2. ConclusionS: The development of irAEs was strongly associated with an ICI benefit, including overall response, PFS, and OS, in 2 separate cohorts of patients with recurrent/metastatic HNC.