Real-world data (RWD) with avelumab in patients (pts) with locally advanced or metastatic urothelial cancer (la-mUC): The AVEBLADDER study.

e16559 Background: Current standard of care for la-mUC pts who show no progression after platinum-based chemotherapy is maintenance with avelumab based on survival improvement (JAVELIN 100; Powles et al. NEJM 2020). However, the available RWD evidence on the use of avelumab in the E.U. is limited and there are concerns about the low uptake of this strategy based on figures from American series (Mamtani R et al; JAMA Netw Open 2023). We present here data on the use of avelumab in a large cohort of pts from different centres in Spain within the academic group GO NORTE. Methods: AVEBLADDER is a retrospective observational analysis in which clinical information was retrieved from pts treated across 14 centres in 13 provinces in Northern Spain. The study population included adult pts diagnosed with la/mUC (January 1, 2021-June 30, 2023) followed from date of diagnosis until death, loss to follow-up or end of study. Median overall survival (OS) was determined using the Kaplan-Meier method. Results: 419 pts were included. Median age was 71 [range 42-88]; 80% were males; 81% had primary bladder tumours and 94% predominant urothelial histology. Seventy three percent of pts had visceral/bony metastases and 59% were unfit for cisplatin. Most common 1 st line treatment (tx) [88%] was platinum-based chemotherapy [median number of cycles 4]. Out of 369 pts who received platinum-based chemotherapy, non-progression (CR, PR or SD) was reported in 230 pts [62%], of whom only 85 pts [37%] received maintenance avelumab. Fifty-eight pts treated with avelumab were evaluable for response: 7 (10 %) achieved a CR, 12 (14%) PR, 22 (26%) SD and 17 (20%) PD. The most common reason for non-receiving avelumab in our series was lack of access/reimbursement according to country/region policy. Overall, 168 pts [40%] started 2 nd line tx and atezolizumab was the most used agent, only 41 pts [24%] received third line tx. With a median follow-up of 11 months, 194 pts [46%] are still alive and median overall survival (OS) is estimated to be 28 months (95% CI 23-not reached) with maintenance avelumab vs 11 months (95% CI 9-13) for those who did not receive this drug. Conclusions: Despite the demonstrated improvement in OS for maintenance avelumab, its uptake in our series was low with roughly 40% of the pts. New policies and better access to the drug will most likely improve these figures and hopefully also the proportion of patients who progress to receive a third line where novel therapies are currently being implemented. AVEBLADDER is a study sponsored by GO NORTE a non-for-profit GU cooperative group.