Durable response after immunotherapy discontinuation for delayed and severe immune-related adverse events: a case report.

Recent studies have shown that immune-related adverse events (irAEs), occurring even after the discontinuation of immune checkpoint inhibitors (ICIs), may be associated with favorable disease outcomes, particularly in patients with melanoma and lung cancer. However, a few clinical cases have been described on the correlation between irAEs and ICIs efficacy in renal cell carcinoma (RCC) patients. This study reports the clinical case of a metastatic RCC patient who has experienced severe immune-related renal toxicity after 19 months of nivolumab use. Despite immunotherapy discontinuation, the patient has maintained clinical benefit and disease progression-free for 3 years. We examined the correlation between the occurrence and the severity of irAEs, treatment discontinuation and clinical benefits. The evidence on ICI retreatment following ICI discontinuation due to irAEs was also reviewed. Lay abstract Immunotherapy has profoundly changed the treatment scenario of cancer patients. However, similar to any oncological therapy, it may cause immune-related adverse events. Cancer patients experiencing immune-related adverse events have a higher probability of better survival outcomes. This correlation has been largely described in patients with melanoma and lung cancer, but only a few data have been reported for genitourinary tumor patients. Here, we report the clinical case of a metastatic renal cell carcinoma patient who has experienced a late-onset and severe immune-related renal toxicity after 19 months of immunotherapy, which led to treatment discontinuation. Despite this, the patient has maintained a clinical benefit and disease progression-free for more than 3.5 years. We reviewed the literature on the correlation between immunotherapy benefit and immune-related adverse events, considering the time of onset, the severity of the adverse events and the concepts of treatment discontinuation and retreatment.