Purpose: To determine the cost-effectiveness of fulvestrant 250 mg compared to 500 mg in postmenopausal women with estrogen receptor-positive metastatic breast cancer and disease progression after antiestrogen therapy.
Methods: A Markov model was constructed to find the incremental cost-effectiveness of fulvestrant 250 mg monthly when compared with the 500 mg monthly in patients with progression after antiestrogen therapy. The model duration was 24 months. Clinical efficacy data inputs were derived from a phase III clinical trial demonstrating a statistically significant increase in progression-free survival in patients receiving 500 mg versus 250 mg. Cost data utilized were all relevant Ambulatory Payment Classification payment rates from the 2011 Medicare Outpatient Prospective Payment System. A Monte Carlo simulation was performed to test the model at various willingness to pay thresholds.
Results: The incremental cost-effectiveness ratio as determined by the Markov model was US$10,972 per month of progression-free survival for the 500 mg dose compared with the 250 mg dose. Using a Monte Carlo simulation, it was found that 500 mg monthly was cost-effective at and above the willingness to pay threshold of US$15,000 per month. A series of one-way sensitivity analyses showed this result is robust to geographical practice variations in costs of drug administration and physician examination.
Conclusion: From a third party payer perspective, the value of fulvestrant 500 mg monthly is dependent on the willingness to pay threshold. Despite a labeling change for fulvestrant in September 2010, fulvestrant 250 mg monthly appears to be a viable option in the target population.