Abstract B080: Safety and efficacy of immune checkpoint inhibitors (ICIs) among older adults with renal cell carcinoma, bladder cancer, and melanoma: visiting an understudied age group

Abstract Background ICls represents a revolutionary advancement in cancer treatment by utilizing the immune system to target tumor cells. However, predicting immune-related adverse events (irAEs) remains challenging. This study aimed to evaluate the clinical and treatment-related predictors of irAEs and treatment efficacy in patients receiving ICls. Methods Patients with melanoma, RCC, or bladder cancer who received ICIs at the American University of Beirut Medical Center were retrospectively reviewed. Patient characteristics, tumor features, treatment response, and irAE details were recorded. Cox regression, chi-squared tests, and binary/logistic regressions assessed the relationships between predictors and outcomes. Age was the main predictor; other predictors were also studied. Results Among 146 patients, the mean age was 67.6 + 13.6 years. 45 patients (31%) had RCC, 45 (31%) had Bladder Cancer, and 56 (38%) had Melanoma. 65 patients (45%) experienced > 1 irAE with a total of 122 irAEs. The most common systems involved were gastrointestinal (17.2%), dermatologic (12.6%), pulmonary (11.8%), endocrine (11.7%), and renal (9.7%). Among 65 patients with = 1 irAE, the mean duration to first irAE was 5.8 + 10.98 months and 28 had irAE CTCAE grade > 3. 34 patients required steroids for irAE management, and 10 patients discontinued immunotherapy due to irAEs. At the univariate level, no predictors were significantly associated with the development of an irAE. Surgery had a protective effect against disease progression (HR= 0.478, p=0.01). Higher Charlson Comorbidity Index (CCl) was associated with higher odds of having irAE grade >3 (OR=1.227, p=0.047). Previous exposure to steroids or chemotherapy shortened the time to the first irAE by 4 months (p=0.026) and 4.2 months (p=0.009), respectively. No associations remained significant at the multivariate level. Conclusions Our analysis suggests that more comorbid patients may have more severe irAEs and that patients with previous exposures to steroids or chemotherapy may have earlier irAEs. These findings suggest that comorbidities and medication history should be factored into irAE risk stratification, particularly among older adults. Citation Format: Abbas Hammoud, Ali Awada, Mohamad Hajjar, Ali Dakik, Michael Romanos, Razane Wehbe, Ali Tarhini, Firas Kreidieh. Safety and efficacy of immune checkpoint inhibitors (ICIs) among older adults with renal cell carcinoma, bladder cancer, and melanoma: visiting an understudied age group [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2025 Oct 22-26; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2025;24(10 Suppl):Abstract nr B080.