Efficacy and Safety of Checkpoint Inhibitors in Clear Cell Renal Cell Carcinoma: A Systematic Review of Clinical Trials

Renal cell carcinoma (RCC) is the most common kidney cancer in adults (approximately 90%), and clear cell RCC (ccRCC) is the most frequent histologic subtype (approximately 75%). We reviewed the safety and efficacy of checkpoint inhibitors (CPIs) in ccRCC, identifying 5927 articles in PubMed, Embase, Cochrane, and Web of Science. Ten randomized control (N = 7765) and 10 non-randomized (N = 572) studies were included. Overall, 4819 patients treated with CPI combinations were compared with everolimus, sunitinib, or placebo. Overall response rates (ORR) were 9–25% with nivolumab (niv), 42% with niv + ipilimumab (ipi), 55.7% with niv + cabozantinib, 56% with niv + tivozanib vs. 5% with everolimus. ORR was 51.5–58% with avelumab + axitinib vs. 25.5% with sunitinib. ORR was 59.3–73% with pembrolizumab + tyrosine kinase inhibitor vs. 25.7% with sunitinib. ORR was 32–36% with atezolizumab + bevacizumab vs. 29–33% with sunitinib. In patients with PD-L1+ve and -ve ccRCC, niv, atezolizumab, ipi, and pembrolizumab were safe and effective alone and when combined with cabozantinib, tivozanib, axitinib, levantinib, and pegilodecakin. Atezolizumab + bevacizumab was safe and effective in ccRCC with high PD-L1 expression. Pembrolizumab was safe and effective in preventing recurrence in ccRCC patients with nephrectomy. Additional randomized, double-blind, multicenter clinical trials are needed to confirm these results.