SOGUG-AVELUMAB_RWD: Comprehensive analysis of real-word data to evaluate the effectiveness and safety of avelumab maintenance therapy in patients with stage IV urothelial carcinoma conducted in Spain.
Authors: Juan Fita Maria Jose , Fernandez Calvo Ovidio , Anido Herranz Urbano , Alvarez Fernandez Carlos , Girones Regina , Gajate Pablo , García Domínguez Rocío , Ros Martinez Silverio , Puente Javier , Blasco Molla Sara , Ore Arce Martin , Noguerón Esther , Fernandez-Freire Ana , Alonso Nieves Del Pozo , Cassinello Javier , Lazaro Quintela Martin , Arranz Fernando , Abad Villar Maria Teresa , Crespo Guillermo , Molina Diaz Aurea 
Published: June 2024

e16561 Background: The recommended treatment for patients with Stage IV Urothelial carcinoma is first-line platinum-based chemotherapy, followed by avelumab maintenance therapy in patients without disease progression. Real-world evidence (RWE) estimates the number of patients treated and the duration of treatments. Our objective was to assess the effectiveness and safety profiles of these patients in routine clinical practice. Methods: We conducted a multicentric, observational study with retrospective and prospective analysis of patients with stage IV Urothelial Carcinoma who started maintenance therapy with avelumab between January 2021 and April 2022 in 22 sites. Retrospective period included data from deceased patients and from alive patients prior to the signing of the informed consent (IC). Prospective period included patients’ data after signature of the IC. Results: Between September 2022 and July 2023, were enrolled 125 patients, 113 of whom were assessable for the analysis (74 alive and 39 deceased). The mean age was 69.6 years, 85.0% were male. Most of the patients had ECOG 1 (63.4%). Regarding the platinum treatment in first line, 54.0% of patients received cisplatin and 46.0% carboplatin, with a median of 4 cycles administered. Best response to avelumab in the retrospective evaluation was progressive disease (PD) in 25.5%, 43.3% stable disease (SD), 16.4% partial response (PR) and 12.4% complete response (CR). In the prospective period 16.7% reported PD, 54.2% SD, 12.5 PR and 14.6% CR. After a median follow up of 11,9 (8,3) months since the start of avelumab, 21 patients (18.6%) continued with avelumab, with a mean (SD) of 33.0 (12.1) cycles, and 81.4% of patients had stopped, with 12.9 (10.6) cycles administered. 67.3% of patients reported PD or exitus through the follow-up. The progression free survival probability (PFS) as primary endpoint was 0.2140, with a median (95% CI) PFS of 10.1 (7.1 – 12.4) months. The PFS probability at 12 months was 0.4492, with 52.2% of patients reporting PD or exitus. Moreover, 2.6% of patients (n=3) reported an exitus, all of them before 12 months, with an overall survival (OS) probability of 0.9542. The 5.3% of patients had SAEs -one resulted in death- most unrelated to avelumab. 39 patients (34.5%) had a total of 82 adverse drug reactions during the treatment period, 4 of them serious and 45.1% probably related to avelumab. The most frequent ADRs were asthenia and pruritus/rash; no SUSAR was reported. Conclusions: These data agree with the results of the phase 3 JAVELIN Bladder 100 trial and other real-world studies, confirming the effectiveness and manageable safety profile of avelumab 1LM in stage IV UC. Nonetheless, we acknowledge the limitations of our research, including its retrospective design. An extension study is being considered in order to have OS data for 24 months.