Two cases of delayed onset of immune‐related adverse events after discontinuation of nivolumab in patients with metastatic renal cell cancer

INTRODUCTION: Delayed onset of immune‐related adverse events following immune‐checkpoint inhibitor discontinuation is underrecognized because of little available evidence. CASE PRESENTATION: A 50‐year‐old man with metastatic renal cell carcinoma (Case 1) and 58‐year‐old woman with renal cell carcinoma and retroperitoneal lymph node metastasis (Case 2) underwent nivolumab therapy. Case 1: Progressive disease forced nivolumab discontinuance after 18 months, and he underwent two courses of tyrosine kinase inhibitor therapy. immune‐related adverse events of pneumonitis, hepatitis, and renal dysfunction were diagnosed 142 days after nivolumab discontinuation, and he recovered with immunosuppressive treatment. Case 2: The immune‐related adverse event of pneumonitis forced nivolumab discontinuance after 14 months, and two courses of tyrosine kinase inhibitor therapy were administered. The immune‐related adverse event of hepatitis was diagnosed 436 days after nivolumab discontinuation, and she recovered with immunosuppressive treatment. CONCLUSION: Two patients with delayed onset of immune‐related adverse events after nivolumab discontinuation were recovered with immunosuppressive treatment.