In hormone receptor-positive, human epidermal growth factor 2-negative (HR+/HER2-) metastatic breast cancer (mBC), cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6is) in combination with an aromatase inhibitor (AI) are the preferred first-line (1L) treatment. Although prior cost-effectiveness models comparing CDK4/6is palbociclib, ribociclib, and abemaciclib have used data from placebo-controlled clinical trials, no analyses in the United States have been conducted using real-world evidence (RWE) for a US Medicare-eligible population. To estimate the long-term clinical outcomes and health care costs of 1L CDK4/6i treatment in patients aged 65 years and older using RWE. We developed a partitioned survival model to project patient time in progression-free and progressed disease health states. Progression-free survival (PFS) and overall survival (OS) curves for palbociclib + AI were obtained from an analysis of patients aged 65 years and older treated 1L for HR+/HER2- mBC using the Flatiron Health Analytic Database (Flatiron). Adjusted comparative effectiveness estimates vs palbociclib + AI for both ribociclib + AI (PFS hazard ratio = 0. 98 95% CI = 0. 86-1. 13; OS hazard ratio = 1. 01 95% CI: 0. 87-1. 18) and abemaciclib + AI (PFS hazard ratio = 0. 99 95% CI = 0. 86-1. 15; OS hazard ratio = 1. 00 95% CI = 0. 84-1. 19) were obtained from the same analysis. All-cause medical costs and CDK4/6i drug costs were based on an analysis of patients aged 65 years and older in Optum Clinformatics DataMart. We used a Medicare perspective over a lifetime horizon for a cohort of patients with mean age of 73. 7 years. Sensitivity analyses were performed to assess the robustness of results to plausible variation in input values. Projected life-years (LYs) with palbociclib + AI, ribociclib + AI, and abemaciclib + AI were similar: 5. 16 (95% credible range CR = 4. 94-5. 35), 5. 12 (95% CR = 4. 53-5. 82), and 5. 16 (95% CR = 4. 49-5. 90), respectively. Total lifetime health care costs were also similar (865, 000 95% CR = 807, 400-925, 000, 866, 800 95% CR = 786, 000-965, 000, and 901, 000 95% CR = 809, 000-1, 004, 600, respectively). Sensitivity analyses further supported no differences in LYs or total costs between CDK4/6is. Based on effectiveness and cost estimates from real-world data, our analyses suggest that palbociclib, ribociclib, and abemaciclib produce similar life expectancy and health care costs in US patients aged 65 years and older with HR+/HER2- mBC.
Sun et al. (Wed,) studied this question.