First-line avelumab for patients with PD-L1-positive metastatic or locally advanced urothelial cancer who are unfit for cisplatin

Background: Cisplatin-based chemotherapy is the most recommended treatment for metastatic urothelial cancer (mUC). However, about 50% of patients are considered to be cisplatin ineligible. Anti-programmed cell death protein 1/programmed death-ligand 1 (PD-L1) therapies have, nevertheless, increased the options available to clinicians and are especially valuable for treating these patients. This study therefore tested the activity and safety of avelumab as first-line therapy for mUC. Patients and methods: Patients with mUC who were ineligible for cisplatin-based chemotherapy were screened centrally for PD-L1 expression and only those with a tumour proportion score ≥ 5% were enrolled in the trial. The primary endpoint was 1-year overall survival (OS), and the secondary endpoints were median OS, median progression-free survival, overall response rate, duration of the response, safety and tolerability. All the survival rates were estimated with the Kaplan-Meier product-limit methodology and compared across groups using the log-rank test. Results: A total of 198 patients were screened, with 71 (35.9%) whose PD-L1 expression was ≥5% enrolled in the study. The median age was 75 years, bladder cancer was the primary tumour in 73.2% of cases and 25.3% had liver metastases. The main reasons for the cisplatin ineligibility were a low rate of creatinine clearance (<60 ml/min), present in 70.4% of patients, and an Eastern Cooperative Oncology Group performance status of 2, which affected 31%. The median OS was 10.0 months (95% confidence interval 5.5-14.5 months) and 43% of patients were alive at 1 year. A complete response was achieved in 8.5% of cases, and 15.5% had a partial response. Adverse any-grade and high-grade events occurred in 49.3% and 8.5% of patients, respectively. A grade 3 infusion reaction was the only high-grade treatment-related adverse event. No treatment-related deaths were reported. Conclusions: This ARIES trial confirmed the activity and safety of avelumab for treating mUC, adding a new therapy option to the armamentarium of checkpoint inhibitors already approved for platinum-ineligible, locally advanced/mUC.