Real-World Outcomes of Ipilimumab Plus Nivolumab for Metastatic Renal Cell Carcinoma: A National Population-Based Cohort Study.

[INTRODUCTION] Immune checkpoint inhibitors are a standard first-line treatment for metastatic renal cell carcinoma (RCC), with combination ipilimumab and nivolumab (ipi-nivo) widely recommended. However, real-world data on its use in Australia remain limited.

[OBJECTIVE] To evaluate real-world outcomes of ipi-nivo for metastatic RCC in the Australian healthcare setting.

[METHODS] We conducted a retrospective cohort study using nationally linked Pharmaceutical Benefits Scheme data and National Death Index records accessed via the Australian Bureau of Statistics DataLab. Patients initiating ipi-nivo for stage IV clear cell RCC between 1 July 2019 and 30 June 2023 were included. Kaplan-Meier analyses and multivariate Cox regression were used to estimate overall survival (OS) and time to treatment discontinuation (TTD). Immune-related adverse events (irAEs) were inferred from incident dispensing of corticosteroids and levothyroxine. Subgroup analyses were performed by age (18-64 versus ≥ 65 years) and sex.

[RESULTS] Among 1334 patients, median OS was 30.0 months with 12- and 24-month survival rates of 72.9% (95% confidence interval [CI] 70.5-75.3) and 56.4% (95% CI 53.7-59.2), respectively. Median TTD was 4.9 months, and 38.5% of patients discontinued treatment during the induction phase. Incident corticosteroid and levothyroxine use occurred in 24.2% and 11.2% of patients, respectively. No significant differences in OS, TTD, or irAE proxies were observed by age or sex.

[CONCLUSIONS] In this national, population-based study, real-world survival outcomes with ipi-nivo for metastatic RCC were shorter than those reported in clinical trials. These findings provide population-level benchmarks from a universal healthcare system and highlight the limitations of applying trial outcomes to unselected real-world populations. By contributing robust, large-scale data from routine practice, this study adds to the global evidence base and supports the integration of real-world data into clinical and policy decisions around immunotherapy.