Real-World Clinical Outcomes with First-Line Systemic Treatment and Avelumab Maintenance in US Patients with Locally Advanced or Metastatic Urothelial Carcinoma: The SPEAR Bladder-II Study

Avelumab first-line maintenance (1LM) is approved for patients with locally advanced or metastatic urothelial carcinoma (la/mUC) who do not have disease progression after platinum-based chemotherapy (PBC). This retrospective study describes real-world treatment patterns and clinical outcomes in patients with la/mUC who initiated first-line (1L) systemic treatments, including avelumab 1LM, within iKnowMed, the US community oncology electronic health records database, between 1 December 2019 and 30 November 2023 and followed through 28 February 2024. In total, 1658 patients with la/mUC initiated 1L treatment: immuno-oncology (IO) monotherapy (41.2%), PBC only (32.4%), PBC followed by avelumab 1LM (11.2%), and other treatments (15.1%). The median OS (95% CI) from the start of 1L treatment was 20.4 (13.8, 30.0), 11.0 (8.5, 14.5), and 14.6 (12.6, 17.3) months for cisplatin-based only, carboplatin-based only, and IO monotherapy, respectively. Among the overall population, 36.1% and 11.8% of patients received second-line (2L) and third-line treatment, respectively. The median (95% CI) OS from the start of avelumab 1LM was 18.5 (13.8, 23.8) months. After discontinuation of avelumab 1LM, 43.5% received 2L treatment, and 59.3% of those received enfortumab vedotin (EV); the median (95% CI) OS from start of 2L EV was 12.7 (7.2, 16.5) months. Survival outcomes among patients treated with avelumab 1LM and 2L EV are consistent with respective clinical trials and other real-world studies.