Efficacy of immune checkpoint inhibitors (ICI) treatment in special populations of metastatic renal cell carcinoma (mRCC).

Abstract

673 Background: Immunotherapies involving a PD-1/PD-L1 immune-checkpoint inhibitor (ICI) are highly effective treatments for mRCC and are now standard of care. Nevertheless, special populations such as patients (pts) with renal impairment (RI) and elderly age were either excluded or underrepresented in registration trials. Here we investigate the efficacy of ICI in mRCC with RI and age above 70 years (yrs). Methods: We utilized the mRCC Princess Margaret database to select pts treated with an ICI agent from May 2005 to May 2018. Renal impairment (RI) was defined as a baseline creatinine > 1.5 ULN or clearance of creatinine < 40 mL/min. Pts were classified as elderly if their age was over 70yrs at the time of ICI initiation. Descriptive statistics and survival analysis were performed. Results: Of 387 pts, 74 received an ICI agent or combination. Mean age was 61yrs and median creatinine was 105 umol/L. Fifty-four pts (73%) were treated with single agent PD-1/PD-L1 ICI and 46 (62%) received treatment as 2nd line. Respectively, 19 (26%), 43 (58%) and 12 (16%) pts were classified as International Metastatic RCC Database Criteria (IMDC) prognostic groups good, intermediate and poor. Of 73 pts with available creatinine levels, 7 (9.5%) were classified as having RI. Ten pts (13.5%) were > 70yrs. Despite not statistically different, pts with RI had worse median overall survival (OS) compared to pts without RI: 7.8 months (m) vs. 28.3m (p=.10). There was no OS difference between pts > 70yrs compared to ≤ 70yrs: not reached (NR) vs. 28m (p=.65). Both RI and elderly patients had no differences in distribution of IMDC prognostic groups compared controls. Conclusions: RI was associated with a non-statistical detriment in OS of mRCC treated with ICI. RI may be a surrogate for comorbid factors that impact OS and needs further analysis in a larger patient sample. Age does not affect ICI efficacy in our cohort. Larger studies to confirm our findings in these special populations are necessary.