Efficacy of immune-checkpoint inhibitors (ICI) in the treatment of older adults with metastatic renal cell carcinoma (mRCC) – an International mRCC Database Consortium (IMDC) analysis

5068 Background: Anti-PD-1/PD-L1 immune-checkpoint inhibitors (ICI) are now a standard of care in metastatic renal cell carcinoma (mRCC). Older adults were underrepresented in registration trials and given that immunological senescence may affect the anti-tumor activity of ICIs, there is uncertainty about the efficacy of ICIs in this population. Here we provide real world data on outcomes of older adults with mRCC treated with ICIs. Methods: Patients with mRCC treated with a PD-1/PD-L1 ICI either as monotherapy or as a combination treatment from 2000 to 2019 were included. Older adult was defined as ≥ 70-years at the time of ICI treatment. Descriptive statistics were summarized in means, medians and proportions. Efficacy was assessed by survival analysis, including overall survival (OS), time to treatment failure (TTF), and overall response rate (ORR). Multivariate analyses adjusted for imbalances in IMDC risk factors. P < 0.05 was considered statistically significant. Results: Of 1427 patients, 397 (28%) were older adults. Mean age of older vs. younger adults was 74 (70-92) vs. 60 (22-69) years. Groups were comparable in terms of gender (Female 28.5% vs. 26.1%, p = 0.36), rates of nephrectomy (21% vs. 18.3%, p = 0.24) and presence of sarcomatoid features (12.3% vs. 17.8%, p = 0.14). Proportion of IMDC risk-groups between older vs. younger adults were as follows: 15.4% vs. 18.2% for favorable, 61.2% vs. 59.1% for intermediate, and 23.4% vs. 22.7% for poor; there was no statistical difference (p = 0.55). ICI was used as 1st line in 40%, 2nd line in 48.5% and 3rd line in 11.5% patients; older adults were less likely to be treated with ICI in 1st line (32.2% vs. 43%, p < 0.01). In terms of survival, older adults had poorer median OS (25.1m vs. 30.8m, p < 0.01) but similar median TTF (6.9m vs. 6.9m, p = 0.40) compared to younger adults. In multivariate analyses, older age was not a predictor of either worse OS (aHR = 1.02, p = 0.86) or TTF (aHR = 0.95, p = 0.59). Older adults had a lower ORR compared to younger (24% vs. 31%, p = 0.01), which was mainly driven by responses in 1st line (31% vs. 44%, p = 0.02) and not observed in 2nd/3rd line (20% vs. 20%, p = 0.86). Conclusions: On multivariate analyses, older adults with mRCC treated with ICI had no difference in OS and TTF when compared to younger adults, despite having lower ORR in 1st line. Our data supports that older age is not an independent risk factor for survival; thus, treatment selection should not be based solely on chronological age.