Case Study: A Japanese patient with metastatic renal cell carcinoma who achieved long‐term treatment‐free survival with pembrolizumab and axitinib in the KEYNOTE‐426 phase III trial of pembrolizumab and axitinib versus sunitinib

INTRODUCTION: Our patient treated with pembrolizumab and axitinib is one of the longest survivors in Japan on KEYNOTE 426, despite adverse events, including delayed‐onset hepatitis. We herein present a detailed clinical course and short discussion on the case. CASE PRESENTATION: This was a 49‐year‐old male with clear cell renal cell carcinoma and lung metastases. After cytoreductive nephrectomy, treatment with pembrolizumab plus axitinib was initiated and the patient demonstrated a radiographic partial response as best response. The main adverse event was pembrolizumab‐induced delayed‐onset hepatitis, which was successfully treated with prednisolone. Pembrolizumab was re‐initiated and completed. CONCLUSION: The survival benefit in the present case may be due to the initial potent anti‐cancer effects of axitinib and durable immune effects of pembrolizumab, leading to long‐term treatment‐free survival.