Salvage ipilimumab associated with a significant response in sarcomatoid renal cell carcinoma

Background Metastatic sarcomatoid renal cell carcinoma (sRCC) is an aggressive variant of RCC with generally poor prognosis. Treatment with vascular endothelial growth factor inhibitors or chemotherapy generates only short-lived responses. Recent research has suggested a role for combination checkpoint inhibition as first line treatment for metastatic sRCC. This therapy consists of induction with cytotoxic T-lymphocyte-associated protein 4 inhibitor, ipilimumab, administered with programmed cell death protein 1 (PD-1) inhibitor, nivolumab. After completion of four cycles of combination therapy, single-agent maintenance nivolumab is recommended until progression. Patients who progress on maintenance nivolumab are switched to alternate therapy. Herein, we present a case of a patient with RCC who progressed on maintenance nivolumab who, on retreatment with ipilimumab, demonstrated a significant response In addition, we summarize important findings to support the role of salvage ipilimumab in patients with sRCC. Case presentation A 46-year-old man presented with flank pain and hematuria, the work up of which noted a left kidney mass for which he underwent nephrectomy and was diagnosed with localized sRCC with 60% sarcomatoid differentiation. Within 3 months of nephrectomy, he presented with recurrent flank pain and was diagnosed with recurrence of disease. He was treated with ipilimumab 1 mg/kg and nivolumab 3 mg/kg for four doses and demonstrated a partial response. He was then transitioned to single agent nivolumab maintenance. After 3 months on maintenance therapy, he was noted to have progression of disease. Given prior response to immune check point combination, it was decided to rechallenge the patient with 1 mg/kg ipilimumab. After two doses of ipilimumab and nivolumab combination therapy, the patient was noted to have a partial response. He maintained a response for an additional 9 months and treatment was eventually discontinued due to grade 3 toxicity and progression. Conclusions This case report demonstrates the utility of retreatment with ipilimumab as a salvage option for patients progressing on maintenance PD-1 inhibitors in metastatic RCC. Further studies are needed to identify predictors of response and toxicity to this approach, as well as the optimal scheduling of ipilimumab with maintenance nivolumab.