Background: Patients with advanced renal cell carcinoma (aRCC) have poor prognosis resulting in significant burden. In the KEYNOTE-581/CLEAR trial, pembrolizumab plus lenvatinib (P+L) as 1L therapy showed statistically significant and clinically meaningful improvements in overall survival (OS), progression-free survival (PFS), and overall response rate (ORR) versus sunitinib in patients with aRCC. This NMA synthesized evidence from randomized clinical trials (RCTs) to indirectly compare the relative treatment effects of P+L vs alternate therapies in treatment-naïve aRCC. Methods: A systematic literature review was conducted to identify systemic therapies in 1L aRCC. A Bayesian NMA with fixed-effect models was performed to indirectly compare P+L to alternate therapies using sunitinib as the common comparator in 1L aRCC. Hazard ratios (HRs) for OS and PFS were calculated with 95% credible intervals (CrIs). NMAs assuming constant hazard ratios (HRs) and time-varying HRs were performed for OS and PFS. For the proportion of patients experiencing response, a binomial likelihood and logit link were used, and relative effects were expressed as odds ratios (OR). Results: A total of 33 unique RCTs met the inclusion criteria and were included in the analyses. The constant HR analysis resulted in no significant differences in OS between P+L and alternatives in network. Results showed statistically significant higher ORR for P+L compared to nivolumab + ipilimumab (N+I) (OR=3.19; 95% CrI: 2.14, 4.82) and pembrolizumab + axitinib (P+A) (OR=1.84; 95% CrI: 1.21, 2.80). The analysis also favored P+L over nivolumab + cabozantinib (N+C) (OR=1.35; 95% Crl: 0.86, 2.12) and avelumab + axitinib (A+A) (OR=1.46; 95% Crl: 0.96, 2.23), but was not statistically significant. The constant HR analysis showed that P+L resulted in a statistically significant improvement in PFS compared to N+I (HR=0.55; 95% CrI: 0.40, 0.75), A+A (HR=0.68; 95% Crl: 0.49, 0.96) and P+A (HR=0.69; 95% CrI: 0.51, 0.94). The analysis also favored P+L over N+C (HR=0.81; 95% Crl: 0.58, 1.14), but was not statistically significant. Conclusions: NMA indicates P+L has higher ORR and improved PFS compared to other regimens in 1L aRCC. No significant differences in OS were observed between P+L and competing interventions.