OBJECTIVES: Endocrine therapy continues to be the optimal systemic treatment for metastatic ER+/HER2- advanced breast cancer. The CDK4/6 inhibitor Palbociclib has recently been shown to significantly improve progression-free survival. The objective of this study was to assess the cost-effectiveness of Palbociclib plus Fulvestrant (PAL+FUL) versus Everolimus plus Exemestan (EVE+EXE) in the treatment of post-menopausal women with ER+/HER2- advanced breast cancer after failure of treatment with non-steroidal aromatase inhibitors (NSAIs) from an Iranian payer perspective.

METHODS: A Markov model was developed to evaluate the costs and effectiveness of PAL+FUL versus EVE+EXE over a 10-year time horizon. The model included 3 health states: responsive/stable disease, progression, or death. Monthly transition probabilities were estimated based on the published clinical trials and network meta-analyses. Time-to-progression and time-to-death were derived from a Weibull and exponential distribution. Direct medical costs including drug acquisition and administration costs, health states associated medical costs, and costs for managing adverse events (AEs) were put in the model. Utilities for each health state and disutilities for AEs were derived from the literature. Costs and effectiveness discounted at 7.2% and 5%, respectively. Finally, Incremental costs per quality-adjusted life years (QALYs) were estimated. One-way and probabilistic sensitivity analysis (PSA) were performed.

RESULTS: PAL+FUL was associated with 1.79 QALYs and total direct costs of $22,517 over 10 years. Compared to EVE+EXE, PAL+FUL provided an additional 0.22 QALYs at an incremental cost of $440. The resulting incremental cost-effectiveness ratio was $1966/QALYs gained. A tornado analysis suggested that the key drivers of our model are Palbociclib and Everolimus acquisition costs. The PSA showed that assuming a willingness-to-pay of 1 GDP/capita ($5400), the probability of Palbociclib to be cost-effective was 65%.

CONCLUSIONS: PAL+FUL can be considered cost-effective compared to EVE+EXE for the treatment of patients with HR+/HER2- metastatic breast cancer patients failing initial therapy with NSAIs in the Iranian healthcare system.