Predictive value assessment of the Meet-URO and IMDC scores in metastatic renal cell carcinoma (mRCC) receiving first-line ICI–ICI vs ICI–TKI combinations (Meet-URO 33 study).

e16509 Background: The prognostic value of the IMDC and Meet-URO scores is well-established in clinical trials and real-world analyses in untreated and pretreated mRCC patients. However, their predictive performance in the novel 1 st line setting of immune-combinations is still unclear. Methods: We conducted an Italian multicenter retrospective-prospective real-world study of mRCC patients receiving 1 st line ICI–ICI or ICI–TKI. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan–Meier method. The predictive value of the Meet-URO score (5 categories) and the IMDC score (3 categories) was assessed using Cox proportional hazards models including formal treatment-by-risk interaction testing in univariable and multivariable analyses. Results: A total of 1907 patients were enrolled from 58 centres and 1511 patients (79%) were included in the analysis. Median age was 65.8 years, 85% had clear-cell histology, 76% received ICI–TKI and 24% ICI-ICI. After a median follow-up of 27.8 months, in the overall population, in the ICI-TKI group and in the ICI-ICI group: mOS was 37.8, 39.0 and 37.8 months, respectively; PFS was 17.9, 19.4 and 13.1 months, respectively. Hazard ratios for ICI–TKI vs ICI–ICI were consistent across all Meet-URO and IMDC groups for both OS and PFS (Table 1). No significant treatment-by-risk interaction was observed for Meet-URO score (OS p=0.73; PFS p=0.86) or IMDC risk group (OS p=0.73; PFS p=0.37). Conclusions: In this large real-world cohort, Meet-URO and IMDC prognostic scores did not show predictive value for selecting between 1 st line ICI–ICI and ICI–TKI combinations. These findings suggest that established risk models should not guide treatment choice between immune-based combinations in mRCC, but other factors should be considered (e.g. metastatic sites, tumor burden). Clinical trial information: CESC IOV 2023-78. Risk group N mOS ICI-TKI vs ICI-ICI (months) OS HR (95% CI) P value mPFS ICI-TKI vs ICI-ICI (months) PFS HR (95% CI) P value Meet-URO score 1 213 NR (≥45.7) vs NR (≥20.6) 1.32 (0.41–4.29) 0.73 34.5 vs 14.2 0.62 (0.31–1.25) 0.86 Meet-URO score 2 442 57.9 vs NR (≥XXX) 0.80 (0.52–1.25) 28.0 vs 26.8 0.85 (0.61–1.19) Meet-URO score 3 351 32.2 vs 37.8 1.05 (0.71–1.56) 18.2 vs 13.1 0.68 (0.49–0.94) Meet-URO score 4 376 25.7 vs 17.6 0.89 (0.63–1.24) 15.0 vs 7.1 0.71 (0.53–0.95) Meet-URO score 5 129 11.5 vs 7.2 0.71 (0.40–1.25) 6.8 vs 3.1 0.71 (0.41–1.21) IMDC favorable 282 57.9 vs NR (≥ 38.4) 1.20 (0.43–3.32) 0.73 39.5 vs 15.0 0.69 (0.36–1.32) 0.37 IMDC intermediate 901 37.2 vs 42.2 0.88 (0.67–1.14) 19.7 vs 15.7 0.74 (0.60–0.91) IMDC poor 328 13.7 vs 16.6 0.94 (0.66–1.32) 9.1 vs 7.1 0.77 (0.57–1.04)