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<0.0001) were significantly lower in patients with SMs. The dismal prognostic impact was observed both with pleura and peritoneum SMs. These 2 sites were not significantly associated. Using multivariate Cox models, SMs remained significantly associated with poor survival, independently of IMDC category, gender, age, and number of previous lines of therapy. Objective response rate in patients with SMs was not significantly different from others patients (16.4 vs 22.1%; p=0.147). SMs were not statistically associated with known poor prognosis metastatic sites (cerebral, bone, and liver.) Conclusions: SMs are a strong independent prognostic impact in patients receiving N for metastatic ccRCC Poor prognostic metastatic sites should be considered when assessing the prognosis of patients with metastatic ccRCC
654MO A phase II prospective trial of frontline cabozantinib in metastatic collecting ducts renal cell carcinoma: The BONSAI trial (Meeturo 2)
