Prognostic stratification by the Meet-URO score in a real-world elderly population of patients (pts) with metastatic renal cell carcinoma (mRCC) receiving cabozantinib: A subanalysis of the prospective ZEBRA study (Meet-URO 9).

637 Background: The combination of neutrophil to lymphocyte (NLR), bone metastases and IMDC score in the novel prognostic Meet-URO score has shown a higher prognostic performance than the IMDC score alone in mRCC pts receiving ≥2nd line nivolumab or cabozantinib in two retrospective analyses and 1st line nivolumab-ipilimumab in a real-world prospective study [http://bit.ly/Meet-URO15_score]. Further validation is needed since this score represents an easy prognostic tool for clinical practice with no additional costs. Methods: A real-world analysis of elderly (≥70 yo) mRCC pts treated with any line cabozantinib was conducted in the multicenter observational prospective Zebra study. Baseline Meet-URO score was assessed. The primary endpoint was overall survival (OS) and the Harrell’s c-index was calculated to compare accuracy of survival prediction of the Meet-URO and IMDC scores. Results: 104 mRCC pts received cabozantinib as 1st (38%), 2nd (20%), 3rd (33%) and 4th (8%) line, with a median follow-up of 11.2 months (mo) and a median overall survival (mOS) of 18.4 mo. According to the IMDC score, favorable- (15%), intermediate- (65%) and poor-risk (19%) pts had a mOS not reached (NR), 15.6 and of 5.7 mo, respectively (p = 0.011). Reclassifying the population according to the Meet-URO score, we observed that group 1 (10%) and group 2 (25%) had both mOS NR, whereas group 3 (33%), group 4 (25%) and group 5 (8%) had a mOS of 13.6, 12.5 and 3.7 mo, respectively (p = 0.001). Moreover, the Meet-URO score maintained its discrimination ability also merging group 1-2 vs 3-4 vs 5 (p < 0.001). NLR < 3.2 was the heaviest component of the score (p < 0.001, mOS 24.8 vs 11.5 mo). The Meet-URO score (using both original with 5 groups and modified with 3 groups) has shown a higher prognostic power than the IMDC score alone (c-index of 0.686 and 0.676 vs 0.622). Conclusions: This analysis confirmed the higher accuracy in survival stratification of the Meet-URO score compared with the IMDC score alone also in a specific population like elderly mRCC pts treated with cabozantinib. NLR was confirmed as a strong prognostic factor with cabozantinib. Further applications of the Meet-URO score in mRCC pts treated with first-line immune-combinations are planned and highly awaited. Clinical trial information: 2018/116/PU .