Complete response to immune checkpoint inhibitors-based therapy in advanced renal cell carcinoma patients. A meta-analysis of randomized clinical trials

Background: A major breakthrough with immunotherapy is its potential to achieve complete responses (CR) in a subset of advanced renal cell carcinoma (RCC) patients. We aim at evaluating the incidence and relative risk (RR) of CR in RCC patients treated with immune checkpoint inhibitors (ICIs). Materials and methods: Searching the MEDLINE/PubMed, Cochrane Library and ASCO Meeting abstracts prospective studies were identified. The proportion of patients with CR events and the derived 95% confidence intervals (CIs) were calculated for each study. Combined relative risks (RRs) and 95% CIs were calculated using fixed- or random-effects methods. The analysis was performed in the intention to treat population, in the PD-L1 expressing (>= 1%) RCC tumors and in patients treated with the combination of ICIs and anti-VEGFR tyrosine kinase inhibitors. Results: Six articles were considered for final analysis (total of 4.531 patients). The incidence of CR was 6.2% with ICIs and 2.6% with SOC. Treatment with ICIs significantly increased the risk of achieving CR compared to SOC (RR = 2.40; P = 0.001). This data was confirmed for patients treated with the combination of ICIs plus anti-VEGFR tyrosine kinase inhibitors (RR = 2.50; P = 0.002). In PD-L1 positive tumors, the incidence of CR was 10.0% with ICIs and 4.0% in the SOC arm (RR = 2.49; P < 0.0001). Conclusions: ICIs provide higher rates of CR compared to SOC, even higher in patients with PD-L1 positive tumors. (C) 2020 Elsevier Inc. All rights reserved.