Nivolumab-Induced, Late-Onset, Steroid-Sensitive, High-GradePneumonitis and Durable Tumor Suppression in Metastatic RenalCell Carcinoma: A Case Report

Nivolumab, an antiprogrammed death-1 checkpoint inhibitor, has been approved for use in unresectable/metastatic renal cellcarcinoma (RCC). Nivolumab-induced pneumonitis, a rare, but often severe and potentially life-threatening immune-relatedadverse event, has been reported, typically, early during the treatment. Due to its low incidence, more studies are needed tobetter elucidate this condition and its possible effects on cancer progression. We now present a 57-year-old Hispanic malepatient with metastatic RCC-clear cell type who, after his 34thcycle of nivolumab (16 months after being on nivolumab),developed a late-onset, immune-related adverse event (IRAE) including a grade 3 pneumonitis, which resolved completely,clinically, and on serial lung imaging with steroids and drug discontinuation. His cancer remained stable with no progressionfor 18 months despite discontinuation of nivolumab which showed tumor progression resistance. This case report is aimed atproviding further information regarding the rare phenomena of a late-onset IRAE, in particular, a grade 3 nivolumab-inducedpneumonitis which also responded rapidly to treatment, as well as at discussing this immunotherapy’s durable tumorsuppressive effect and a possible associated factor to this phenomenon