Pembrolizumab plus axitinib versus sunitinib in metastatic renal cell carcinoma: outcomes of Japanese patients enrolled in the randomized, phase III, open-label KEYNOTE-426 study

Background In the phase III open-label KEYNOTE-426 (NCT02853331) study, first-line pembrolizumab and axitinib improved overall survival (OS) and progression-free survival (PFS) versus sunitinib for metastatic renal cell carcinoma (mRCC). KEYNOTE-426 evaluated patients enrolled from 25 sites in Japan. Methods Patients enrolled in Japan were included in this post hoc subgroup analysis. Adults with clear cell mRCC were randomly assigned 1:1 to receive intravenous pembrolizumab 200 mg every 3 weeks plus 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 as assessed by blinded independent central review. Objective response rate (ORR) and safety were secondary endpoints. Results The Japanese subgroup comprised 94 patients (pembrolizumab–axitinib, n = 44; sunitinib, n = 50; 11% of the intent-to-treat population). Median time from randomization to data cutoff (January 6, 2020) was 29.5 months (range 24.6–37.3). Consistent with the intent-to-treat population, the OS, PFS, and ORR suggested improvement with pembrolizumab–axitinib versus sunitinib in the Japanese subgroup. Grade ≥ 3 treatment-related adverse events (TRAEs) occurred in 70% of patients receiving pembrolizumab–axitinib versus 78% receiving sunitinib; 11 (25%) patients receiving pembrolizumab–axitinib and 13 (27%) patients receiving sunitinib discontinued the study medication due to AEs. TRAEs led to the discontinuation of pembrolizumab, axitinib, pembrolizumab–axitinib, or sunitinib in 32%, 34%, 14%, and 20%, respectively. No deaths from TRAEs occurred. Conclusions Efficacy outcomes for the Japanese subgroup were consistent with those of the global population. Safety in Japanese patients was consistent with the results from the global population.