Clinical outcomes and treatment patterns of maintenance avelumab in locally advanced or metastatic urothelial carcinoma: a multicenter collaborative study.

Background: The JAVELIN Bladder 100 trial demonstrated improved overall survival (OS) with maintenance avelumab in patients with locally advanced or metastatic urothelial carcinoma UC (la/mUC) who achieved disease control following first-line platinum-based chemotherapy (1 L-PBC). However, real-world data on eligibility, utilization, and outcomes of maintenance avelumab therapy remain limited.

Methods: This retrospective study included patients with la/mUC who received 1 L-PBC. Eligibility for maintenance avelumab therapy was determined based on the best overall response to 1 L-PBC, with patients who achieved stable disease or a partial or complete response considered eligible. Survival outcomes were analyzed using the Kaplan-Meier method. Multivariate Cox regression analysis was used to identify prognostic factors among patients with la/mUC who received maintenance avelumab.

Results: Of 161 prospective patients, 67.1% were eligible for maintenance avelumab therapy, and 46.3% of eligible patients received the treatment. The median progression-free survival (PFS) following avelumab initiation was 10.2 months, whereas the median OS was not reached. Prognostic factors associated with PFS included the presence of liver metastases, elevated C-reactive protein (> 1.0 g/dL), and administration of more than five cycles of 1 L-PBC. Adverse events occurred in 60% of patients treated with avelumab, with 16% experiencing grade 3-4 adverse events.

Conclusion: We emphasize the real-world applicability of maintenance avelumab for Japanese patients with la/mUC. Maintenance avelumab demonstrated favorable survival outcomes, consistent with clinical trial data. Identifying prognostic factors and optimizing treatment sequencing are essential strategies for improving outcomes in this patient population.