First-line pembrolizumab-axitinib versus sunitinib in metastatic RCC: subgroup analysis of patients enrolled in the phase 3 KEYNOTE-426 in Eastern Asia.

Background: The phase 3 open-label KEYNOTE-426 study demonstrated that first-line pembrolizumab plus axitinib improved overall survival (OS) and progression-free survival (PFS) versus sunitinib for metastatic renal cell carcinoma (mRCC) in a global population. This subgroup analysis investigated the efficacy and safety of pembrolizumab-axitinib versus sunitinib in patients enrolled in KEYNOTE-426 in East Asia (Japan, South Korea, and Taiwan).

Methods: Adults with clear cell mRCC were randomly assigned 1:1 to receive intravenous pembrolizumab 200 mg every 3 weeks with oral axitinib 5 mg twice daily or oral sunitinib 50 mg once daily (4 weeks on/2 weeks off). Dual primary endpoints were OS and PFS, assessed by blinded independent central review. Secondary endpoints were objective response rate (ORR) and safety.

Results: The East Asian subgroup comprised 130 patients (pembrolizumab-axitinib, n = 62; sunitinib, n = 68; 15.1% of the global intention-to-treat population). Compared with sunitinib, pembrolizumab-axitinib OS hazard ratio (HR) was 0.85 [95% confidence interval (CI) 0.50-1.44; 36-month rates, 62.9% and 58.8%, respectively] and PFS HR was 0.59 (95% CI 0.38-0.92) in favor of pembrolizumab-axitinib. ORR favored pembrolizumab-axitinib (64.5% vs 44.1% for sunitinib). The results were generally consistent with the intention-to-treat population. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 69.4% of patients on pembrolizumab-axitinib and 74.6% on sunitinib; 16 (25.8%) patients on pembrolizumab-axitinib and 17 (25.4%) patients on sunitinib discontinued due to adverse events. No deaths from TRAEs occurred.

Conclusion: Pembrolizumab-axitinib improved efficacy for East Asian patients with untreated clear cell mRCC, consistent with results from the global population. Safety was manageable. ClinicalTrials.gov identifier: NCT02853331.