Disease control with prior platinum-based chemotherapy is prognostic for survival in patients with metastatic urothelial cancer treated with atezolizumab in real-world practice

Abstract

Introduction: Atezolizumab, programmed-death ligand-1 (PD-L1) inhibitor, is a novel treatment option for patients with metastatic urothelial cancer (mUC). Clinical prognostic factors, survival outcomes and safety of patients with mUC treated with atezolizumab, in a real-world setting, were investigated.

Methods: 62 patients with mUC, treated at the Institute of Oncology Ljubljana, between May 8^th, 2018 and Dec 31^st, 2019, were included. Response rates and immune-related adverse events (irAE) were collected. Progression-free survival and overall survival times were assessed using the Kaplan–Meier method. Cox proportional hazards model was applied to identify the factors affecting survival.  

Results: Of 62 patients, 5 (8.1%) have not been evaluated yet and 20 (32%) died prior to first radiographic evaluation. We observed clinical benefit in 19 (33%), objective response in 12 (21%) and complete response in 5 (9 %) patients. Median overall survival for the whole population was 6.8 (95% CI: 2,6-11,0), for chemo-naïve 8.7 (CI 95%:0.8-16.5) and for chemo–exposed group 6.8 (CI 95%:3.7-10) months. At 5.8 (0.3 – 23.1) months median follow-up, the median duration of response was not reached. IrAE occurred in 20 (32 %) patients and 7 (11%) of them discontinued the treatment. Multivariant analysis in platinum-treated showed that treatment- free interval more than 6 months is prognostic for OS.

Conclusion: Responses to atezolizumab led to long disease remission in a subset of our patients. The mOS in our real-world population was compromised by a large percentage of patients with poor ECOG PS. Treatment free interval from chemotherapy is associated with longer survival of platinum-treated patients with mUC receiving further atezolizumab.