A Case of a Durable Partial Response to Late-Line Axitinib Following Prior Use of Tyrosine Kinase Inhibitors in Metastatic Papillary Renal Cell Carcinoma.

Introduction: Metastatic papillary renal cell carcinoma (PRCC) is associated with a poor prognosis. Many patients with PRCC respond to first- and second-line systemic chemotherapy treatments; however, few respond to late-sequence treatment. We describe a case of a long-term response to fourth-line axitinib after the use of tyrosine kinase inhibitor therapy for metastatic papillary renal cell carcinoma. Case Presentation: A 37-year-old male presented with hematuria and left back pain. Following systemic examination, he was diagnosed with left renal cell carcinoma cT3aN0M1. He underwent left radical nephrectomy. The pathological diagnosis was PRCC type 2. After using sunitinib, cabozantinib, and nivolumab, axitinib was selected as fourth-line systemic therapy, resulting in a reduction in multiple liver metastases and 15 months of response. Conclusion: Late-sequence treatment with axitinib following prior use of tyrosine kinase inhibitor therapy resulted in a long-term response in a patient with metastatic papillary renal cell carcinoma.