Cost-Effectiveness of Capivasertib as a Second-Line Therapy for Advanced Breast Cancer

Background: Capivasertib, a first-in-class AKT inhibitor, was recently approved as a second-line treatment for advanced breast cancer. However, capivasertib is expensive, raising questions over its economic value. This study provides the first evidence on the cost effectiveness of adding capivasertib to endocrine therapy (fulvestrant) for patients with PIK3CA/AKT1/PTEN-altered, hormone receptor-positive (HR⁺) human epidermal growth factor receptor 2-negative (HER2^-) advanced breast cancer.

Methods: A Markov model was built to compare the costs and effectiveness of three treatment strategies. The first strategy involved adding capivasertib to fulvestrant for all patients, while the second strategy involved adding it for only postmenopausal women. The third strategy involved treatment with fulvestrant alone. Analyses were conducted from a US payer perspective over a lifetime horizon. Costs were measured in 2023 US dollars, and effectiveness was measured in life years (LYs) and quality adjusted life years (QALYs), discounted at 3% per year. One-way sensitivity analyses, probabilistic sensitivity analyses, and scenario analyses were conducted to assess the robustness of results.

Results: The addition of capivasertib to fulvestrant for all patients was associated with $410,765 higher costs and 1.46 additional quality adjusted life years (QALYs) compared with fulvestrant alone, resulting in an incremental cost effectiveness ratio of $280,854/QALY. The strategy of adding capivasertib for only patients who are postmenopausal was extended dominated, i.e., yielded fewer QALYs at a higher cost per QALY than if capivasertib was added for all patients. These results were found to be robust in sensitivity and scenario analyses.

Conclusions: At its current price, our analysis suggests that the addition of capivasertib to fulvestrant as a second line treatment is not cost effective versus fulvestrant alone at a willingness-to-pay threshold of $100,000/QALY. The price of capivasertib will need to be reduced by nearly 70% (to $7000 per cycle) for it to become cost effective.