Is Alpelisib Plus Fulvestrant Cost-Effective for Treating PIK3CA-Mutation, HR+/HER2- Advanced Breast Cancer in the USA?

Background and objective: There is a considerable survival benefit of alpelisib in patients with PIK3CA-mutated, hormone receptor-positive and human epidermal growth factor receptor 2-negative advanced breast cancer (HR+/HER2- ABC), yet the financial burden may limit its use. Therefore, this study evaluated the cost-effectiveness of alpelisib plus fulvestrant in patients with PIK3CA-mutated, HR+/HER2- ABC in the USA.

Methods: A Markov model was constructed to simulate the progression of PIK3CA-mutated, HR+/HER2- ABC. Efficacy and safety data were derived from the SOLAR-1 trial. A parametric survival model was used to explore the long-term effect. From a US payer perspective, only direct medical costs were considered. The cost data were estimated based on local pricing and relevant literature. The health outcomes were expressed in quality-adjusted life years (QALYs). Model stability was assessed using one-way sensitivity analysis and probability sensitivity analysis. Subgroup analyses were performed to explore cost-effectiveness outcomes for patients with different clinical characteristics.

Results: The QALY increased by 0.28 with alpelisib plus fulvestrant with an additional cost of $94,345.87 compared with placebo plus fulvestrant, leading to an incremental cost-effectiveness ratio (ICER) of $340,153.30/QALY gained. Sensitivity analyses suggested that the model is most sensitive to the price of alpelisib. At a willingness-to-pay (WTP) threshold of $150,000/QALY, alpelisib plus fulvestrant was cost effective when the cost of alpelisib was less than $71 per 300 mg (36.5 % of the original price), whereas this cost would be less than $168 per 300 mg (86.5 % of the original price) at a WTP threshold of $300,000/QALY. In addition, alpelisib + fulvestrant was not cost effective in all subgroups compared with placebo + fulvestrant at the WTP threshold of $150,000/QALY. In contrast, at the WTP threshold of $300,000/QALY, alpelisib + fulvestrant was cost effective in nearly all subgroups except for endocrine-sensitive patients.

Conclusion: At current drug prices, alpelisib plus fulvestrant is not cost effective for patients with PIK3CA-mutated, HR+/HER2- ABC from a US payer perspective. Given the considerable progression-free survival (PFS) and overall survival (OS) benefits observed with alpelisib in this setting, further discussion and negotiation of the price of alpelisib are warranted to provide more favorable economic outcomes and thereby increase the value of the alpelisib plus fulvestrant regimen in patients.