Avelumab first-line maintenance treatment in patients with locally advanced or metastatic urothelial carcinoma: real-world results from a Korean expanded access program.

Background: The JAVELIN Bladder 100 phase 3 trial demonstrated the efficacy and safety of avelumab administered as first-line (1L) maintenance treatment in patients with advanced urothelial carcinoma (UC) without disease progression after 1L platinum-based chemotherapy. This study provides the first real-world data from Korea regarding avelumab 1L maintenance treatment, comprising data obtained from a nationwide expanded access program (EAP). Methods: This open-label EAP was conducted at five centers from September 2021 until June 2023. Eligible patients had unresectable locally advanced or metastatic UC and were progression free after 1L platinum-based chemotherapy. Patients received avelumab 10 mg/kg intravenously every 2 weeks per local prescribing information. Safety and effectiveness were assessed by treating physicians according to routine practice. Results: Overall, 30 patients were enrolled. At initial UC diagnosis, 20 patients (66.7%) had stage 4 disease and 12 (40.0%) had visceral metastases. The most common 1L chemotherapy regimen was gemcitabine + cisplatin (21 patients; 70.0%). All but one patient (96.7%) had received 4-6 cycles of 1L chemotherapy. The median interval from end of 1L chemotherapy to start of avelumab was 4.4 weeks. Median duration of avelumab treatment was 6.2 months (range, 0.9-20.7); nine patients (30.0%) received >12 months of treatment. Adverse events related to avelumab occurred in 21 patients (70.0%) and were grade ≥3 or classified as serious in three patients (10.0%). Median progression-free survival was 7.9 months (95% CI, 4.3-13.1). Overall survival was not analyzed because only one patient died. Conclusion: Results from this EAP demonstrated the clinical activity and acceptable safety of avelumab 1L maintenance treatment in Korean patients with advanced UC, consistent with previous studies.