Abstract
BACKGROUND The efficacy and safety of re-challenge with immune checkpoint inhibitors after immune-related adverse events have not been established. We report a case of successful re-administration of nivolumab in metastatic renal cell carcinoma after discontinuation due to immune-related adverse events. CASE REPORT Laparoscopic nephrectomy was performed on a 52-year-old man diagnosed with renal cell carcinoma pT1bN0M0. After surgery, left adrenal and lung metastases appeared. Nivolumab was administered as a sixth-line therapy, and he achieved a partial response, but interstitial pneumonia occurred. He was diagnosed with grade 2 immune-related adverse events, and nivolumab treatment was discontinued. Interstitial pneumonia was well controlled by steroids. He maintained a partial response for a long time, and the lung metastases disappeared 7 months after discontinuation. However, bilateral lung metastases reappeared 10 months after the discontinuation. We decided to re-administer nivolumab, while carefully monitoring the patient and fully explaining the risk of recurrence of immune-related adverse events. After 5 cycles of re-administration, computed tomography revealed a reduction in metastases without re-activation of interstitial pneumonia. He experienced a grade 1 fever the day after re-administration, but continued nivolumab therapy without other adverse events. After 7 cycles of re-administration, the lung metastases increased, and nivolumab treatment was terminated. Two months later, a grade 2 interstitial pneumonia recurred, but improved rapidly with oral steroids. CONCLUSIONS For patients who have discontinued immune checkpoint inhibitors due to immune-related adverse events, re-challenge of immune checkpoint inhibitors may be an option after explaining the risk of relapse of immune-related adverse events.