Purpose: Three CDK4/6 inhibitors, palbociclib (PAL), ribociclib (RIB), and abemaciclib, when combined with letrozole (LET), have been approved as first-line therapy for postmenopausal women with metastatic HR+, HER2- breast cancer. However, an economic evaluation of these newer therapies is currently lacking. The purpose of this article is to evaluate the cost-effectiveness of PAL or RIB for the treatment of advanced HR+, HER2- breast cancer in the United States.
Methods: A Markov simulation model was constructed using data from published clinical trials evaluating PAL and RIB. Three simulated treatment strategies included PAL + LET, RIB + LET, or LET alone. The main outcome measures were simulated progression-free survival (PFS), overall survival (OS), costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).
Results: Simulated median OS was 38.9 months for PAL + LET and 33.0 months for LET alone. Simulated median OS for RIB + LET was 43.3 months. Compared to LET alone, PAL + LET provided an additional 0.48 QALYs, on average, with an ICER of $634,000 per QALY gained; RIB + LET provided an additional 0.86 QALYs, on average, with an ICER of $440,000 per QALY gained. At current prices, neither PAL nor RIB was cost-effective, assuming a willingness-to-pay threshold of $100,000 per QALY gained. To reach such a cost-effectiveness threshold, PAL and RIB prices must decrease by approximately 70%.
Conclusion: Despite significant gains in progression-free survival over letrozole alone, the addition of palbociclib or ribociclib in the treatment of advanced HR+, HER2- breast cancer is not cost-effective in the United States given current drug prices.
Keywords: Advanced breast cancer; Cost-effective analysis; Hormone receptor positive; Letrozole; Palbociclib; Ribociclib.