Avelumab maintenance in patients with metastatic urothelial carcinoma in a real-life expanded-access program (EAP).

708 Background: This study evaluates the real-world efficacy and safety of avelumab maintenance therapy in metastatic urothelial carcinoma (mUC) patients who have not progressed following first-line platinum chemotherapy, using data from the EAP. Methods: The primary endpoint was the overall survival (OS), progression-free survival (PFS) and secondary endpoints included safety. PFS and OS were estimated by using the Kaplan-Meier method. Results: One hundred seventeen patients who received at least one cycle of Avelumab. The median number of first-line platinum-based chemotherapy cycles was 5 (range, 3-6). Patients’ characteristics were illustrated in Table 1. The median follow-up was 12.1 months. The 12-month OS rate was 78% (95% CI, 74.5%-79%), while the median OS was not reached. The 12-month PFS rate was 32% (95% CI, 29%-35%) and the median PFS was 5.3 months (95% 3.4–7.1). In univariate analysis, the median PFS were 2.9 vs 5.4 months in patients with or without liver metastases (p=0.001) and 2.8 vs 5.3 months, in patients with hemoglobin levels below or higher than 10 mg/dl(p=0.06), 8.8 vs 4.1 months in patients with lymph nodes only versus other site metastases(p=0.05), respectively. However, the median PFS were 5.6 vs 4.9 months in first-line cisplatin base chemotherapy versus carboplatin (p=0.7), 7.3 versus 4.9 months in 4≤ cycle chemotherapy versus 4 &gt;cycle(p=0.4), and 5.7 versus 5.3 months in response to first line chemotherapy (CR vs PR and Stabil response) (p=0.4) were not statistically significant for PFS. Thirty-one percent of patients experienced a treatment-related adverse event of any grade, and 9 (7.6%) of patients had a grade 3–4 treatment-related adverse event. Conclusions: Avelumab demonstrated effectiveness and tolerability as a maintenance treatment for mUC patients who had not progressed following first-line platinum-based chemotherapy regardless of first line chemotherapy regimen, chemotherapy cycles and response to first line chemotherapy. Liver metastases, only lymph node metastases and hemoglobin level significant factors on PFS. Patient Characteristics (n=117) n % Age (median, years) : 66 (43-84) Male Sex 94 80.3 Site of Primary Tumor Bladder 93 79.5 Renal Pelvis 12 10.3 Ureter 10 8.5 Urethra 2 1.7 Histological Subtype Urothelial Carcinoma 112 95.7 Mixed Histology (urothelial+variant) 5 4.3 ECOG-PS 0 51 43.5 1 64 54.8 2 2 1.7 Baseline Creatinine Clearance &lt;60 ml/min 48 41 Baseline Hemoglobin concentration &lt;10 g/dl 18 15.4 Tobacco Use Current 16 13.7 Previous 70 59.8 Never 24 20.5 Unknown 7 6 Metastatic Site at Baseline Visceral 79 67.5 Liver 9 7.7 Lymph Node Only <jats:td colsp