OBJECTIVES : Locally advanced or metastatic urothelial carcinoma (la/mUC) of the bladder and urinary tract has poor prognosis. In the JAVELIN Bladder 100 (JB100) trial, avelumab maintenance + BSC, as treatment for la/mUC that has not progressed following first-line platinum-containing chemotherapy, led to significant gains in median OS (21.4 vs 14.3 months; HR, 0.69 [95% CI, 0.56-0.86]) and PFS (3.7 vs 2.0 months; HR, 0.62 [95% CI, 0.52-0.75]) vs BSC alone. We developed a UK based model to predict life-years (LYs) and quality-adjusted life-years (QALYs) with avelumab maintenance + BSC vs BSC alone for la/mUC.

METHODS : A partitioned survival analysis was created over a lifetime horizon to estimate outcomes associated with avelumab + BSC vs BSC alone. Efficacy, safety and utility data from JB100 were analyzed, with flexible parametric survival analyses conducted and clinically validated to estimate pre- and post-progression LYs and QALYs. Structural uncertainty was tested through extensive scenario analyses for utility values, extrapolations using different time-to-event distributions, and consideration of a treatment waning effect.

RESULTS : In the base case using generalized gamma distributions for OS for both arms, avelumab increased survival by 1.00 LYs and 0.61 QALYs. A PFS benefit was seen consistently across parametric distributions, meaning that la/mUC patients treated with avelumab + BSC are expected to have a longer pre-progression period with a better quality of life in comparison to BSC alone. Scenario analyses indicated that LY and QALY gains were sensitive to alternative OS extrapolations for both arms.

CONCLUSIONS : Avelumab maintenance immunotherapy following first-line chemotherapy represents a novel treatment strategy for la/mUC that has not progressed with platinum-containing chemotherapy. Due to improved survival associated with avelumab when compared with poor prognosis associated with BSC alone, avelumab would likely meet the end-of-life criteria established by NICE and, subject to regional pricing arrangements, has the potential to be cost-effective in the UK.