Background: Nivolumab (N) has been approved for the treatment of mRCC after failure of 1 or 2 tyrosine kinase inhibitors (TKI) based on the results of Checkmate 025 study. Right after approval, we initiated the NIVOREN GETUG-AFU 26 study (NCT03013335), a French multicenter prospective study to evaluate safety and efficacy of N in a “real world setting”. Methods: Patients (pts) with clear cell mRCC could be enrolled if they had received at least one TKI. Compared with the pivotal trial, inclusion criteria allowed patients with more than 2 previous lines of treatment, including previous mTOR inhibitors, ECOG PS 2, asymptomatic brain metastases (BM) or impaired renal function. The primary objective of the study was the safety of N, efficacy being the main secondary objective. Between February 2016 and June 2017, 729 pts have been enrolled. We report the results from the first 528 pts. Results: All pts had clear cell mRCC, median age was 64, 77.2% were male. ECOG PS was > 1 in 73 pts (14.7%), 27.5% pts had received prior everolimus, 29.7% pts had received more than 2 previous lines, IMDC risk groups were 19%/54.9%/26.1% for good/intermediate and poor risk respectively; 69 (14%) pts had BM at screening. With a median follow up of 13.1 months, median duration of treatment was 4.1 months [0-15.6], with 31.4% of pts still on therapy. Treatment discontinuation due to adverse event (AE) occurred in (48) 13.3% pts . 64 serious related AE have been reported in 52 pts (9.9%) including 7 renal failures and 6 pneumonitis. Median PFS was 4.4 months 95%CI[3;4.6] . At the time of this analysis, 170 pts have died and 12 months OS rate was 66.4% 95%CI[ 61.7; 70.7]. In subgroups analysis, ECOG-PS > 1 (Hazard Ratio (HR) = 2.450 [1.704;3.523]), more than 2 previous lines (HR = 1.442 [1.059;1.963]) and prior use of everolimus (HR = 1.704 [1.250;2.322]) were associated with reduced OS in univariate analysis. Conclusions: We report the first analysis of the largest prospective real world setting study of N in mRCC. NIVOREN study demonstrates that N safety and efficacy in a “real world” prospective study are comparable to the pivotal study. Clinical trial information: NCT03013335