Long-term outcome and safety in patients treated with immune checkpoint blockade therapies for urothelial carcinoma: Experience from real-world clinical practice

474 Background: Anti-tumor activity and manageable safety profile of immune checkpoint blockade therapies (ICT) have been demonstrated in previous clinical trials in patients with metastatic urothelial carcinoma. To the best of our knowledge, very limited real-life data is available with the long follow-up time that confirms the durable antitumor activity and safety of ICT. In this study, we reported the real-life results of 56 months follow-up data of urothelial carcinoma patients who were treated with ICT. Methods: Metastatic urothelial carcinoma patients treated with at least one course of ICT included in the study. The primary endpoint was the overall response rate (ORR); secondary endpoints were overall survival (OS), progression-free survival (PFS), duration of the ICT treatment, and safety. Median follow-up, PFS, and OS were estimated by using the Kaplan-Meier method. Results: Data of 185 eligible patients were analyzed, 11.9% of these patients received the ICT as the first line, 76.8 % as the second line, and 11.3 % as the third or more line of treatment. The median age of the patients was 66 years, and 156 (84.3%) were male (37-86). The majority of patients (93.5%) had ECOG PS scores of 0–1 and primary tumor in the bladder was predominant (86.7%). The median follow-up time was 47(1.15-56) months. The complete response rate to ICT, partial response rate, and ORR were 10.3% (n = 19), 19.5% (n = 36), and 29.8% (n = 55), respectively. The median duration of response was 33.1 months (95% CI, 16.5–49.7). Of the fifty-five patients who responded to treatment, 28 (51%) had an ongoing response at the time of the analysis. Median PFS and OS was 3.8 (2.6–5.1) months and 8.9 (6.8–11.1) months, respectively. 56-month PFS and OS rate was 9.2% and 11.4%, respectively. 56-month PFS and OS rate for CR and PR was 56.2% and 20%, respectively. Fifty-nine percent of patients experienced a treatment-related adverse event of any grade, and 32 (17.3%) of patients had a grade 3–4 treatment-related adverse event. Because of treatment-related side effects, treatment was discontinued in 8 (4.3%) patients and adverse event that required systemic steroid use was reported in only 13 (7%) patients. Four patients (2.2%) died due to treatment-related causes. Conclusions: This 56-month analysis of real-world data confirms the durable response and long-term survival with ICT in metastatic urothelial carcinoma patients. The safety profile was consistent with prior reports, and no new safety signals emerged.