Primary Renal Tumour Response in Patients Treated with Nivolumab for Metastatic Renal Cell Carcinoma: Results from the GETUG-AFU 26 NIVOREN Trial

Primary tumour response may impact therapeutic strategies in metastatic renal cell carcinoma (mRCC) but remains unknown in the era of immune checkpoint inhibitors. We aimed to describe the response of the primary tumour in patients who did not undergo upfront cytoreductive nephrectomy (uCN) and were treated with nivolumab in the GETUG-AFU-26 NIVOREN phase 2 trial. Primary tumour response was prospectively assessed, as well as the overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Among 720 patients, 111 did not undergo uCN, mainly patients with intermediate (45%) and poor (49%) International mRCC Database Consortium (IMDC) risk. In the 111 patients, nivolumab was used in the second line for 63% of patients and the third line or more for 37%, with an ORR of 16% (95% confidence interval [CI] 1025%); with a median follow-up of 24.5 mo (95% CI 21.6–27.1), median PFS was 2.7 mo (95% CI 2.5–4.0) and median OS was 15.9 mo (95% CI 9.5–19.8). A total of 67 patients had an evaluable primary renal lesion, four of whom (6%) experienced shrinkage of more than 30%. Overall, patients who did not undergo uCN had adverse baseline characteristics and nivolumab activity against the primary tumour was limited. Patient summary: In this report, we observed that nivolumab was associated with a limited response of the primary tumour in previously treated patients with metastatic kidney cancer.