The authors approached this analysis from the perspective of an American payer using a two-year time horizon as this is what was available from IMvigo130 results. A partitioned survival model was utilized with three states: pre progression, progression, and death. The proportion of each state was estimated by digitizing the progression-free and overall survival curves from IMVigor130, then fitting parametric models to the curve to estimate outcomes. The comparison groups were atezolizumab + platinum combination therapy compared to platinum chemotherapy with pembrolizumab at progression. Public health utility information for the pre-progression state was extrapolated from Keynote-052, and information for the progressed state was extrapolated from Keynote-045. Costs were derived from 4th quarter 2019 average sales prices as published by the Center for Medicare and Medicaid Services.
The results of this analysis are shown below.
Using a one-way sensitivity analysis, the authors found that the cost of pembrolizumab at progression, cost of atezolizumab with chemotherapy, and the overall survival hazard ratio of atezolizumab with chemotherapy impacted the results of the model. None of these sensitivity results crossed the 150,000 willingness to pay threshold.
Overall, based on their results, the authors concluded that the addition of atezolizumab to chemotherapy in first-line therapy for advanced urothelial carcinoma does not appear to be cost-effective in the first line, though it may approach cost-effectiveness with a 33% reduction in the cost of atezolizumab. Limitations of the model include the fact that it is a projection model rather than based on real-world data, and the inherent limitations of a willingness to pay threshold.
Presented by: Ali Raza Khaki, MD, Medical Oncology Fellow, University of Washington and Fred Hutchinson Cancer Center, Seattle, WA
Written by: Alok Tewari, MD, Ph.D., Medical Oncology Fellow at the Dana-Farber Cancer Institute, at the 2020 American Society of Clinical Oncology virtual annual meeting (#ASCO20), May 29th-May 31st, 2020
- Galsky MD et al. Atezolizumab with or without chemotherapy in metastatic urothelial cancer (IMvigor130): a multicentre, randomised, placebo-controlled phase 3 trial. The Lancet. Vol. 395, Issue 10236, P1547-1557, May 16, 2020.