Prognosis impact of serous metastases (SMs) in clear cell renal cell carcinoma patients in the GETUG-AFU-26 NIVOREN phase II trial

e16566 Background: Nivolumab monotherapy (N) is a standard of care for patients with metastatic clear cell renal cell carcinoma (ccRCC) after failure of antiangiogenic therapies. IMDC criteria is the established prognostic model in anyline of systemic treatment including with N. While liver, bone and brain have been reported to convey a dismal prognosis, little is known about the pejorative prognostic impact of serous metastatic sites (pleura, peritoneum, pericardium) in patients receiving anti-PD (L) -1 treatment. Methods: We aimed to assess survival, and activity of N in patients included in the GETUG-AFU 26 NIVOREN phase II prospective trial ( NCT03013335 ), according to serous metastases (SMs). Results: Overall, 720 patients with metastatic ccRCC, and treated with N. Baseline RECIST metastases data were available for 708 patients included in this analysis. Among them, 142 (20%) had SMs (pleura, n=91 ; peritoneum, n=50 ; pericardium, n=1). Median PFS (4.5 vs 2.6 mo ; HR :1.31 ; p=0.0079), and OS (26.1 vs 15 mo ; HR :1.67 ; p