Efficacy of atezolizumab in patients resistant to platinum-based chemotherapy. Results of the AURORA-RU Study: Atezolizumab in UROthelial cancer: Real-world Analysis of RUssia

Background. The decade-long use of checkpoint inhibitors in real-world clinical practice in Russia allowed to treat hundreds of patients with urothelial malignancies. The AURORA-RU Phase IV observational Russian study was initiated to evaluate the efficacy of atezolizumab in patients with urothelial carcinoma resistant to platinum-based chemotherapy. This article is based on an analysis conducted at a median follow-up of 60.7 months and provides data on treatment efficacy in Russian patients receiving second-line and subsequent lines of systemic therapy. Aim. To evaluate the clinical efficacy of atezolizumab monotherapy in patients with urothelial carcinoma of the upper and lower urinary tract progressing on platinum-based chemotherapy in a real-world clinical setting. The primary endpoints were progression-free survival (PFS) and overall survival (OS). Secondary endpoints included subgroup analyses of efficacy based on the line of therapy (including the subgroup with early progression after neo/adjuvant chemotherapy [NACT/ACT]), age cohort, metastatic sites, and primary tumor location (bladder vs. upper urinary tract). Materials and methods. The study included data from 152 patients with verified muscle-invasive locally advanced and metastatic urothelial carcinoma who received PD-L1 inhibitor (atezolizumab) monotherapy across 13 centers in the Russian Federation between 2019 and 2025. Atezolizumab treatment was administered to patients who progressed on platinum-based chemotherapy. More than half of the patients (55.9 %) were over 65 years of age. The cohort consisted of 75.0 % men and 25.0 % women. The majority of patients (78.3 %) had a primary tumor located in the bladder. PD-L1 inhibitor therapy was administered as second-line treatment in 57.9 % of cases, while one in five patients (21.7 %) received third-line treatment. In 86.8 % of cases, treatment was administered without prior assessment of PD-L1 expression levels. Results. In the overall cohort, the median PFS reached 5.5 months, with 36-month and 48-month PFS rates of 15.9 % and 9.9 %, respectively. The median OS was 12.0 months; 21.9 % of patients survived 3 years, and 14.3 % of patients remained under observation for five years. In patients transitioning to immuno-oncology treatment after rapid progression following NACT/ACT, the median OS was 17.4 months. The median OS for second-line therapy was two-fold higher than for third-line therapy: 13.9 months versus 6.1 months. High treatment efficacy was noted in patients over 70 years of age (median PFS of 8.7 months; median OS of 14.9 months). Conclusion. In real-world practice, PFS and OS rates were comparable to those reported in registration trials and other real-world evidence studies. The lack of PD-L1 expression testing generally did not affect the efficacy of immuno-oncology therapy in patients with urothelial carcinoma.