Immune checkpoint inhibitors in the peri-operative setting in renal cell carcinoma: A meta-analysis of the randomized clinical trials.

682 Background: Localized and oligometastatic resectable renal cell carcinoma (RCC) have moderate to high rates of relapse after surgery and evidence regarding the efficacy of perioperative treatments is conflicting. The risk of relapse varies across studies and there is a need to define the benefit/risk of immune checkpoint inhibitors (ICI) in this setting to optimize their use. Methods: A meta-analysis of the randomized phase 3 trials of peri-operative treatment with anti-PD-1/PD-L1 agents or anti-PD1/antiCTL4 in combination was conducted. The primary outcomes of interest were disease-free survival (DFS) and overall survival (OS). Secondary outcomes of interest were the proportion of grade 3-4 adverse events (AE) according to CTCAE 5.0. Subgroup analyses were performed according to clinically relevant characteristics. Statistical heterogeneity assumption was evaluated by the χ²-based Cochran’s Q test and quantified with the I² statistic. All statistical analyses were performed using Stata software (StataCorp LLC), version 16. Results: Published results of 4 phase 3 trials were included, involving 3393 patients. 1695 patients received ICI (anti-PD1: 900 patients; anti-PD-L1 390 patients, antiPD1/anti-CTLA4 405 patients) while 1712 received no active treatment (1297 placebo, 415 observation). ICI did not show to increase DFS (Hazard ratio (HR) 0.84 95% CI 0.69-1.03 p 0.10) or OS (HR 0.73 95% CI 0.40-1.34 p 0.31). High-grade AEs were 2.6 times more frequent in the immunotherapy arm (OR 2.64 95% CI 1.54 – 4.68 p < 0.001) while high grade treatment-related AEs were 8 times more frequent in the experimental arm (OR 8.60 95% CI 3.23-22.91 p < 0.001). Interestingly, subgroup analyses showed statistically significant differences favoring the experimental arm in females (HR 0.72 95% CI 0.55-0.93 p 0.01), in patients with sarcomatoid differentiation (HR 0.59 95% CI 0.403-0.88 p 0.010) and PD-L1 positive tumors (HR 0.74 95% CI 0.61-0.90 p 0.003). No significant effect was found in patients according to age, type of nephrectomy (radical vs. partial), and stage (M1 without evidence of disease vs M0 patients). Conclusions: The introduction of anti-PD-(L)1 +/- anti-CTLA-4 agents in the adjuvant setting of RCC might benefit selected RCC patients, although with increased toxicity. Longer follow-up of the conducted studies is needed to establish a potential benefit in long-term survival.