First-line Treatment of Metastatic Renal Cell Carcinoma in the Immuno-oncology Era: Systematic Review and Network Meta-analysis

Combination treatments with immuno-oncology (IO) agents and IO agents plus a vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR-TKI) have been approved for first-line treatment of patients with metastatic renal cell carcinoma (mRCC). No direct comparisons have been performed among these treatment options. We performed a systematic review and network meta-analysis to compare and rank the available regimens for first-line treatment in terms of survival benefit and efficacy. In accordance with the Preferred Reporting Items for Systematic Review statement, a systematic search of reported studies was performed in MEDLINE, the Cochrane Central Register of Controlled Trials, and EMBASE up to May 31, 2019. Network meta-analysis models were adjusted using the Bayesian method. Four randomized clinical trials, with a total of 3758 patients, met the inclusion criteria. Considering systemic therapy, 1880 patients had received sunitinib and 550, 432, 442, and 454 patients had received ipilimumab plus nivolumab (ipi + nivo), pembrolizumab plus axitinib (pembro + axi), avelumab plus axitinib (avelu + axi), and atezolizumab plus bevacizumab (atezo + bev). No difference was found in overall survival between ipi + nivo and pembro + axi for the intention to treat population (hazard ratio [HR], 1.34; 95% credible interval [CrI], 0.92-1.97). No difference was found in progression-free survival among the treatments. The overall response rate (ORR) was superior with pembro + axi and avelu + axi compared with the ORR with the other treatments (atezo + bev vs. pembro + axi: HR, 0.66; 95% CrI, 0.52-0.84; ipi + nivo vs. pembro + axi: HR, 0.73; 95% CrI, 0.59-0.90; atezo + bev vs. avelu + axi: HR, 0.55; 95% CrI, 0.43-0.71; avelu + axi vs. ipi + nivo: HR, 1.66; 95% CrI, 1.31-2.12), with no differences across them (HR, 1.21; 95% CrI, 0.95-1.53). In the present indirect comparison, for an intention to treat population, we found no survival differences between pembro + axi and ipi + nivo. All treatments showed better progression-free survival compared with sunitinib that was similar among them. The combination of an IO agent (pembrolizumab or avelumab) and axitinib seemed to be the most effective therapy for the ORR.