Real-world evidence from a single U.K. cancer center for atezolizumab in second-line setting in advanced urothelial cancer: Moving beyond clinical trials.

Abstract

461 Background: Atezolizumab is approved for use in advanced urothelial cancer in second line setting after platinum based chemotherapy. We conducted a retrospective study to evaluate clinical outcomes in patients treated in a single UK cancer centre with Atezolizumab for advanced urothelial cancer. Methods: Data was collected from electronic records for patients treated with Atezolizumab for advanced urothelial cancer patients between January 2019 to June 2021. Patients with histologically proven advanced urothelial cancer, PS 0-1, GFR > 30 ml/min by Cockcroft-Gault formula, who had progressed after platinum based chemotherapy were eligible. Maximum duration of treatment allowed was 24 months as per National Cancer Drugs Fund criteria. Initially 3 weekly cycles using Atezolizumab at a dose of 1200 mg was used, patients received 4 weekly dose once 1680 mg dose was available. Kaplan Meier survival estimates were used to calculate progression free survival and overall survival. Results: 32 patients received Atezolizumab between Jan 2019 to June 2021. The mean age was 70.6 years (range 44-88). 10 patients had ECOG PS 0, 22 patients had PS 1. Male 19, Female 13. At the time of analysis, 9 out of 32 patients were alive, 2 patients had completed 24 months of treatment and had no evidence of disease progression. Total 297 cycles of Atezolizumab were delivered (190 cycles were delivered at 3 weekly intervals, while 107 were delivered 4 weekly). The median progression free survival was 24.290 weeks (95% CI: 23.202-25.378), and the median overall survival was 40.860 weeks (95% CI: 19.788-61.932). 10 patients (31.2%) were alive at 12 months, 8 patients (25%) were alive at 18 months. The number of patients with toxicity of grade ≥3 were 4.There were no treatment related deaths. Conclusions: Atezolizumab is effective and well tolerated in patients with advanced urothelial cancer in second line setting. Durable responses were noted with 25% of patients alive at 18 months.