Possibilities of long-term atezolizumab immunotherapy in patients with metastatic urothelial cancer.

e14628 Background: Results from various studies have indicated that atezolizumab can be an effective and well-tolerated treatment option for patients with advanced and metastatic urothelial cancer. However, the landscape of oncological practices in Uzbekistan reflects a scarcity of experience and data concerning the utilization of atezolizumab in the treatment of patients afflicted with urothelial cancer. This research endeavors to bridge this gap by contributing. Methods: In our retrospective study, a total of 44 patients were selected, with a mean age of 64.5±7.6 years, diagnosed with stage IV urothelial cancer and the presence of distant metastases in the lungs, bones, and liver. There were 28 (63.6%) males and 16 (36.4%) females. Group 1 included 18 (40.9%) patients with elevated PD-L1 levels SP142 – IC 2/3, receiving atezolizumab at 1200 mg intravenously (IV) on day 1 of each 21-day cycle + cisplatin at a dose of 70 mg/m 2 body surface area (BSA), IV, on day 1 of each cycle, and gemcitabine at a dose of 1000 mg/m 2 BSA, IV, on days 1 and 8 of each cycle. Group 2 included 26 (59.1%) patients receiving standard chemotherapy (cisplatin + gemcitabine) in the same regimens. Immunohistochemical analysis was performed using the Ventana Bench Mark Ultra automated stainer with Ventana PD-L1 SP142 monoclonal antibodies. Results: The research was conducted from September 2019 to May 2023, and the administered treatment was the first line for these patients. Treatment was administered until disease progression was registered or until the development of unacceptable toxicity. Grade I toxicity was not observed in both groups. Grade II toxicity in Group 1 was noted in 3 (16.7%), and in Group 2 - in 4 (15.4%). Grade III toxicity was identified in 9 patients (50.0%) in Group 1 and 14 patients (53.8%) in Group 2. Grade IV toxicity was encountered in 6 patients (33.3%) in Group 1 and 8 patients (30.8%) in Group 2. Hematological toxicity, regardless of atezolizumab use, predominated among the III and IV degrees of toxicity. The median overall survival in Group 1 was 14.8 months (95% CI: 12.8-16.2), while in Group 2, it was 11.9 months (95% CI: 9.3-13.5). Progression-free survival in Group 1 was 6.8 months (95% CI: 5.1-7.4), and in Group 2, it was 4.3 months (95% CI: 3.8-5.7). The objective response rate in Group 1 was 44.5%, and in Group 2, it was 38.5%. Conclusions: Atezolizumab, used in combination with standard platinum-based chemotherapy in the first line, improves treatment outcomes for metastatic urothelial cancer by increasing overall survival and progression-free survival without causing an increase in the toxicity of the administered therapy.