Unveiling the cost-effectiveness of CDK4/6 inhibitors in treating patients with HR+/HER2- metastatic breast cancer: A closer look at nonmedication expenses.

person Asal Pilehvari UVA Comprehensive Cancer Center, Charlottesville, VA info_outline Asal Pilehvari, Wen You, Gretchen Genevieve Kimmick, Gloribel Bonilla, Roger Anderson

Authors person Asal Pilehvari UVA Comprehensive Cancer Center, Charlottesville, VA info_outline Asal Pilehvari, Wen You, Gretchen Genevieve Kimmick, Gloribel Bonilla, Roger Anderson Organizations UVA Comprehensive Cancer Center, Charlottesville, VA, University of Virginia, Charlottesville, VA, Duke University Medical Center/Duke Cancer Institute, Durham, NC Abstract Disclosures Research Funding American Cancer Society Background: Cyclin-dependent kinase (CDK)4/6 inhibitors have significantly enhanced survival outcomes in postmenopausal patients diagnosed with HR+ MBC. Their integration with endocrine therapy (ET) has become the standard of care in MBC treatment lines. There are limited economic evaluations of these innovative, yet costly, therapies. This study assesses the cost-effectiveness of these drugs using EHR derived data and administrative claims to estimate cost. Methods: We used the nationwide EHR-derived Flatiron Health (FH) de-identified database to identify 3,879 patients receiving 1st line (1L) treatment for HR+ MBC (2,137 received CDK4/6i+ET and 1,742 received ET alone) between Feb 2015 and Nov 2021. SEER-Medicare claims data was used to supplement the missing cost info in the FH database to quantify monthly medication costs, drawing data from Medicare patients continuously enrolled in PARTs A, B, and D between 2015 to 2021 for at least 24 months and specific to therapeutic approaches for MBC and overall healthcare costs. The costs were adjusted by the patient characteristic: age, race, specific ET or CDK4/6i drug, and Medicare dual eligibility. The effectiveness was measured as progression-free duration in months. All costs were adjusted for inflation. The Incremental Cost Effectiveness Ratio (ICER) analysis was conducted to examine the cost-effectiveness of CDK4/6i as compared with ET alone. Results: Average estimated monthly medication costs were $12,524 and $322 for CDK4/6i+ET and ET alone, respectively . On average, CDK4/6i+ET increased the estimated medication costs by $235,564 over the time to first progression and was associated with a gain of 3.2 months of progression-free survival as compared to ET alone, resulting in an ICER of $73,098 per month without progression. At a willingness-to-pay of $65,000 per month without progression, both groups have 50% probability of being considered cost-effective. Notably, the average estimated monthly non-medication costs (total costs-medication costs) for the CDK4/6i+ET group were $2,278 compared to $4,265 for the ET alone group (p<0.001). On average, CDK4/6i+ET decreased the estimated non-medication costs by $ 22,427. For non-medication costs, the ICER drops to $7,178 per month without progression making the CDK4/6i+ET the dominant cost-effective choice over ET alone. Conclusions: Cost-effectiveness of treating HR+ MBC patients is primarily driven by the cost of CDK4/6i drug prices. However, findings highlight significantly lower overall non-medication healthcare costs using CDK4/6i+ET compared to ET alone in 1L treatment. These cost savings, however, are offset by the high medication costs of CDK4/6i. Thus, lowering the market cost of CDK4/6i drugs or targeting those who can benefit the most could shift the balance in favor of a cost-effective benefit from Medicare perspective.