Real-world effectiveness and healthcare utilization of nivolumab for recurrent and/or metastatic squamous cell carcinoma of head and neck (R/M SCCHNC): A real-world population-based study.

e18040 Background: Nivolumab was the first immunotherapy to have shown efficacy in platinum-resistant recurrent and/or metastatic squamous cell carcinoma of head and neck (R/M SCCHNC) in the CheckMate-141 trial. Prior to its introduction, patients with R/M SCCHNC had limited treatment options after progression on first-line treatments. We conducted a real-world population-based retrospective observational study to examine the real-world survival outcomes and resource utilization of patients with R/M SCCHNC who were treated with nivolumab. Methods: Patients with R/M SCCHNC were included in the study if they received nivolumab between January 17 th 2018 to August 31 st 2022 in Ontario, Canada. The maximum follow-up date is August 31 st , 2023. Overall survival (OS) and time-to-treatment discontinuation was assessed using Kaplan-Meier, and the Cox proportional hazard model was used to explore the association between baseline patient characteristics and all-cause death. Cumulative incidence of having an emergency department visit and hospitalization were estimated using the cumulative incidence function, taking death as a competing event. Results: A total of 498 patients who received nivolumab for R/M SCCHNC (Mean age 62.9, 78.7% male) were included in the study. The median survival time for all-cause death was 6.0 months (95% CI: 5.0 – 7.3) and median time to nivolumab discontinuation was 2.6 months (95% CI: 2.3 – 3.0). The overall survival probability at 1 year and 2 years were 31.1% (95% CI: 27.5 – 36%) and 18.5% (95% CI: 14.7 – 22.3%), respectively. A sensitivity analysis comparing OS between older patients Age ≥ 75yo (1yr: 37%, 95% CI: 24.3 – 49.7%; 2 yrs: 19%; 95% CI: 7.8 – 30.2%) and younger patients aged < 75yo (1yr: 31%, 95% CI: 26.5 – 35.5%; 2 yrs: 18.4%, 95% CI: 14.4 – 22.5%) demonstrated no significant differences (p-value 0.73). At 1-year following starting nivolumab, the cumulative incidence of emergency department visits was 50.6% (95% CI: 46.1 – 55.0%), emergency department visits leading to hospitalization was 49.6% (95% CI: 45 – 54.0%), and direct hospitalization is 22.7% (19.0 – 26.6%). Conclusions: In this real-world study, we demonstrated that survival outcomes of nivolumab were similar to those observed in CheckMate-141 trial. Moreover, we found that at one year after starting nivolumab, more than half of the patients had a hospitalization event, suggesting notable healthcare resource utilization in this population.