Cost-Effectiveness Analysis of Fourth- or Further-Line Ripretinib in Advanced Gastrointestinal Stromal Tumors

Weiting Liao; Huiqiong Xu; David Hutton; Qiuji Wu; Kexun Zhou; Hui Luo; Wanting Lei; Mingyang Feng; Yang Yang; Feng Wen; Qiu Li

doi:10.3389/fonc.2021.692005

Cost-Effectiveness Analysis of Fourth- or Further-Line Ripretinib in Advanced Gastrointestinal Stromal Tumors

Front Oncol. 2021 Dec 6:11:692005. doi: 10.3389/fonc.2021.692005. eCollection 2021.

Authors

Weiting Liao^{1

2}, Huiqiong Xu¹, David Hutton³, Qiuji Wu^{1

2}, Kexun Zhou^{1

2}, Hui Luo⁴, Wanting Lei^{1

2}, Mingyang Feng^{1

2}, Yang Yang^{1

2}, Feng Wen^{1

2}, Qiu Li^{1

2}

Affiliations

¹ Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, China.
² West China Biomedical Big Data Center, Sichuan University, Chengdu, China.
³ Department of Health Management and Policy, University of Michigan, Ann Arbor, MI, United States.
⁴ State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, China.

Abstract

Background: The INVICTUS trial assessed the efficacy and safety of ripretinib compared with placebo in the management of advanced gastrointestinal stromal tumors.

Method: We used a Markov model with three health states: progression-free disease, progression disease and death. We parameterized the model from time-to-event data (progression-free survival, overall survival) of ripretinib and placebo arms in the INVICTUS trial and extrapolated to a patient's lifetime horizon. Estimates of health state utilities and costs were based on clinical trial data and the published literature. The outcomes of this model were measured in quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness ratios (ICERs). Uncertainty was tested via univariate and probabilistic sensitivity analyses.

Results: The base-case model projected improved outcomes (by 0.29 QALYs) and additional costs (by $70,251) and yielded an ICER of $244,010/QALY gained for ripretinib versus placebo. The results were most sensitive to progression rates, the price of ripretinib, and health state utilities. The ICER was most sensitive to overall survival. When overall survival in the placebo group was lower, the ICER dropped to $127,399/QALY. The ICER dropped to $150,000/QALY when the monthly cost of ripretinib decreased to $14,057. Probabilistic sensitivity analyses revealed that ripretinib was the cost-effective therapy in 41.1% of simulations at the willingness-to-pay (WTP) threshold of $150,000.

Conclusion: As the fourth- or further-line therapy in advanced gastrointestinal stromal tumors, ripretinib is not cost-effective in the US. Ripretinib would achieve its cost-effectiveness with a price discount of 56% given the present effectiveness.

Keywords: cost-effectiveness; fourth-line or further; gastrointestinal stromal tumor; resistant; ripretinib.