The evidence supporting this protocol is provided by a phase 3 multicentre international randomised trial (JAVELIN Bladder 100) involving 700 patients comparing best supportive care (BSC) and maintenance avelumab with BSC alone, in patients with unresectable locally advanced or metastatic urothelial cell carcinoma, who had not progressed after 4-6 cycles of first-line platinum-based chemotherapy.r
Between May 2016 and June 2019, 350 patients were randomised to receive BSC and avelumab (10 mg/kg two weekly until progression or toxicity), commencing within 4 to 10 weeks of platinum-based chemotherapy and 350 patients were randomised to receive BSC alone.
The primary end point was overall survival (OS), which was assessed in the overall population, and in the PD-L1-positive. Secondary end points were progression-free survival (PFS), objective response (ORR), time to response, duration of response, disease control, and safety.
Maintenance avelumab plus BSC significantly prolonged OS, as compared with BSC alone, among patients with urothelial cell carcinoma who had disease that had not progressed with first-line chemotherapy.
Efficacy
After a median follow up of 19 months, the median OS in the overall population was 21.4 months in the avelumab group and 14.3 months in the BSC alone arm (HR 0.69; 95% CI 0.56-0.86; P=0.001). 1 year overall survival was 71.3% in the avelumab arm vs 58.4% in the BSC arm.r
Avelumab significantly prolonged progression free survival with median PFS 3.7 months in the avelumab arm vs 2.0 months in the BSC arm (HR 0.62; 95% CI 0.52-0.75).
ORR was 9.7% (6% complete response, 3.7% partial response) in the avelumab arm vs 1.4% with BSC alone. Disease control rate was 41.1% in the avelumab arm vs 27.4% in the BSC arm.r
Kaplan-meier estimates of OS in the overall populationr

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Kaplan-meier estimates PFS in the overall populationr

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There were no reported clinically significant differences in quality of life scores or patient reported outcomes between groups.r
Toxicity
All cause adverse events occurred in 98.0% of the group receiving avelumab compared with 77.7% in the control group, grade 3 or above adverse events incidence was 47.4% and 25.2% respectively. There were two treatment-related deaths (0.6%) in the avelumab arm which were attributed to the trial treatment (urosepsis/possible central venous catheter infection and ischemic/thrombosis-related events).r
Adverse events (safety population) r

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