Effectiveness of nivolumab-based immunotherapy and prognostic stratification by the Meet-URO score in real-world older patients with metastatic renal cell carcinoma

Introduction: The incidence of renal cell carcinoma (RCC) increases with age, yet older patients (≥70 years) are underrepresented in clinical trials. Evidence on the efficacy of immune checkpoint inhibitors (ICIs) and on reliable prognostic tools for this population remains limited. We aimed to evaluate the effectiveness of nivolumab-based immunotherapy in older patients with metastatic RCC (mRCC) and assess the prognostic accuracy of the International Metastatic RCC Database Consortium (IMDC) and Meet-URO scores. Materials and Methods: This multicenter study included 889 patients with mRCC treated with nivolumab alone or in combination with ipilimumab, using data from the Meet-URO 15 study and the Italian Expanded Access Program. Progression-free survival (PFS), overall survival (OS), and prognostic factors were analyzed by age group (<70 and ≥ 70 years) using Kaplan-Meier curves and multivariate models. Results: Median OS and PFS were similar between younger and older patients (mOS: 23.5 vs. 25.1 months, HR: 1.02, p = 0.82; mPFS: 6.28 vs. 7.82 months, HR: 0.93, p = 0.40). The Meet-URO score outperformed the IMDC score in prognostic accuracy (p < 0.001), particularly in older patients. Non-clear cell histology was linked to shorter PFS (HR: 1.37, p = 0.05), while prior nephrectomy improved OS (HR: 0.55, p = 0.001). Limitations include the retrospective design and treatment heterogeneity. Prospective validation is needed. Discussion: In this large real-world cohort, outcomes in older patients with mRCC receiving nivolumab-based immunotherapy were comparable to those in younger patients. The Meet-URO score improved prognostic stratification and supported clinical decision-making.