Prognostic Stratification by the Meet-URO Score in Real-World Older Patients With Metastatic Renal Cell Carcinoma (mRCC) Receiving Cabozantinib: A Subanalysis of the Prospective ZEBRA Study (Meet-URO 9).

BACKGROUND: The addition of neutrophil to lymphocyte ratio (NLR) and bone metastases to the IMDC classification provided by the Meet-URO score, resulted in higher prognostic accuracy in metastatic renal cell carcinoma (mRCC) patients receiving ≥2nd line nivolumab or cabozantinib in 2 retrospective analyses and 1st line nivolumab-ipilimumab in an expanded access programme. Prognostic estimates for older mRCC patients might be key for clinical decision-making.

METHODS: The outcome of real-world older (≥70 years) mRCC patients treated with any line cabozantinib within the multicenter observational prospective ZEBRA (Meet-URO 9) study was analyzed according to the baseline Meet-URO score. The primary endpoint was overall survival (OS). The discriminative ability by Harrell's c-index and calibration were assessed to compare the Meet-URO and IMDC scores.

RESULTS: A total of 104 mRCC patients received cabozantinib as 1st (38%), 2nd (20%), or ≥3rd (41%) line. With a median follow-up of 11.2 months, the median OS (mOS) was of 18.4 months. According to the IMDC score, favorable (15%), intermediate (65%) and poor-risk (19%) patients had a mOS not reached, of 15.6 and 5.7 months respectively (p = .011). According to the Meet-URO score groups, mOS was not reached in both group 1 (10%) and group 2 (25%), while in group 3 (33%), group 4 (25%) and group 5 (8%) mOS was of 13.6, 12.5, and 3.7 months, respectively (p < .001). The discriminative ability of the Meet-URO score was maintained by merging groups 1 to 2 vs. 3 to 4 vs. 5 (p < .001). The Meet-URO score (with either the original 5-group stratification or the modified 3-group one) showed higher accuracy than the IMDC score (c-index of 0.686 and 0.676 vs. 0.622).

CONCLUSION: This analysis confirmed the prognostic accuracy of the Meet-URO score in older mRCC patients treated with cabozantinib and its role as a convenient tool for informing the patient and clinical decisions.