Concomitant medications and survival outcomes in patients receiving avelumab maintenance for advanced urothelial carcinoma: sub analysis of Meet-URO 25 study

Background Concomitant medications may impair immune checkpoint inhibitor (ICI) activity through modulation of the gut microbiome and systemic immunity. While a medication-based risk model (drug score) has been validated in pan-cancer cohorts, evidence in advanced urothelial carcinoma (aUC) remains limited. This study assessed the association between concomitant medications and survival in patients receiving avelumab maintenance in the Meet-URO 25 cohort. Methods We retrospectively analyzed patients with aUC treated with avelumab maintenance in several Italian centers. The drug score assigned 1 point each for antibiotics and PPIs, and 2 points for corticosteroids ≥ 10 mg prednisone equivalent. Patients were classified as good (0), intermediate (1-2), or poor (3-4) risk. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan–Meier and Cox models. Results Among 251 patients (median age 72; 82% male), use of interfering medications was low. Drug score distribution was 76.5% good, 21.9% intermediate, and 1.6% poor risk. Median PFS was 8.0, 3.9, and 2.9 months, respectively; median OS was 27.6, 14.0, and 3.4 months. Drug score, ECOG performance status, and bone metastases were independent prognostic factors. Conclusions The drug score showed significant prognostic value in aUC patients receiving avelumab maintenance, supporting its integration into risk stratification for ICI-treated UC.