Eligibility gap scoring across first-line targeted and immunotherapy trials and real-world cohorts in metastatic renal cell carcinoma

First-line treatment for metastatic renal cell carcinoma (mRCC) has shifted toward immune checkpoint inhibitor-based combinations, but pivotal trial populations may differ from patients treated in routine practice. We developed an eligibility gap (EG) score to visualize selected eligibility-related baseline characteristics across first-line mRCC studies. Phase III randomized controlled trials (RCTs), published real-world data (RWD) cohorts, and the original AGEHA-JPN cohort were analyzed. The EG score integrated median age, prior nephrectomy rate, and IMDC risk distribution on a 0–99.9 scale. Thirty-six datasets were included: 10 RCTs, 25 published RWD cohorts, and AGEHA-JPN. Median EG scores were higher in RCTs than RWD cohorts (74.0 vs 60.3; p < 0.001), mainly reflecting younger age and higher prior nephrectomy rates, whereas IMDC-domain scores were similar. Asian RWD cohorts had lower median scores than non-Asian RWD cohorts (50.7 vs 64.5). Sensitivity analyses using alternative domain and sample-size weighting preserved the RCT–RWD separation. The EG score provides a descriptive framework for contextualizing selected baseline differences between trial and real-world populations. However, it does not capture factors such as histology, comorbidity, or metastatic burden and is not a comprehensive measure of trial eligibility, generalizability, or prognosis.