Real-world overall survival (OS) of patients (pts) with metastatic urothelial carcinoma (mUC) receiving first-line (1L) systemic therapy (tx): Results from IMPACT UC II.

529 Background: Urothelial cancer (UC) is the most common urinary system cancer. The IMPACT UC II study aimed to assess tx patterns and clinical outcomes in pts with mUC treated with platinum-based chemotherapy or immuno-oncology monotherapy (IO-mono) in 1L. Methods: This was a retrospective claims analysis of pts diagnosed with mUC from July 2015 to June 2020 and continuously enrolled for 6 mo before and ≥6 mo after index date (ie, date of first claim) using Optum Research Database, which represents ≈8% of commercially insured and 18% of Medicare Advantage (MAPD) populations. Pts were followed up until disenrollment, study end in August 2021, or death. Analyses examined OS and time to 2L tx (TT2L) in three tx cohorts: cisplatin (cis)-based, carboplatin (carbo)-based, or IO-mono. Results: Of 3,006 pts diagnosed with mUC, 1,037 received 1L tx: 365 (35.2%) with cis-based tx; 337 (32.5%) with carbo-based tx, and 335 (32.3%) with IO-mono. Among treated pts, mean age was 72.5 years (SD, 9.9 years), 72.3% were male, and 77.4% were MAPD insured. At baseline, pts receiving cis-based tx had a lower percentage of ≥3 comorbidities (defined by National Cancer Institute criteria): cis-based, 22.2%; carbo-based, 39.5%; and IO-mono, 45.1%. Among 290 pts (27.9%) receiving 2L tx, carbo-based tx had the shortest median TT2L (5.7 mo). Pts receiving cis-based tx had the longest median OS (27.4 mo). Relative to cis-based tx, multivariable–adjusted mortality risk was 2 times higher with IO-mono (hazard ratio [HR], 2.0; 95% CI, 1.6-2.5) and 1.5 times higher with carbo-based tx (HR, 1.5; 95% CI, 1.3-1.9) (Table). Conclusions: This study shows that, before avelumab 1L maintenance approval, the majority of pts did not receive any systemic anticancer tx. following mUC diagnosis. In 1L, after multivariable adjustment (including for baseline comorbidities), real-world OS was lower in pts receiving carbo-based tx and IO-mono compared with cis-based tx. Future research should examine outcomes with newer standard of care.[Table: see text]