Composite Inflammatory Score for Predicting Progression‐Free Survival in Metastatic Clear Cell Renal Cell Carcinoma Treated With First‐Line Toripalimab Plus Axitinib

ABSTRACT Routine inflammatory and nutritional markers may help stratify progression risk in metastatic clear cell renal cell carcinoma during immunotherapy‐based treatment. This single‐center retrospective study included 237 patients who received first‐line toripalimab plus axitinib therapy. Ten indices were natural‐log transformed and standardized, and domain‐based selection yielded a compact composite inflammatory score (COMP‐IS), which was internally validated using 1000 full‐pipeline bootstrap resamples. The primary endpoint was progression‐free survival (PFS). During a median follow‐up of 19.84 months for PFS, 124 events occurred. COMP‐IS comprised the neutrophil‐to‐lymphocyte ratio, C‐reactive protein‐to‐albumin ratio (CAR), and prognostic nutritional index. After adjusting for the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) score, each standard deviation increase in COMP‐IS was associated with shorter PFS (hazard ratio, 3.48; 95% confidence interval, 2.74–4.42). The apparent concordance index (C‐index) for COMP‐IS was 0.767, with a bootstrap‐corrected C‐index of 0.755, compared with corrected C‐indices of 0.694 for CAR and 0.565 for the IMDC score. Adding IMDC to COMP‐IS resulted in a corrected C‐index of 0.756. In an exploratory post hoc comparison, the published Meet‐URO risk groups had an apparent C‐index of 0.593. COMP‐IS demonstrated prognostic discrimination for PFS in this cohort; however, only internal validation was performed. Its clinical utility therefore remains uncertain, and independent external validation and prospective evaluation are needed before routine clinical use.