Economic evaluation of fulvestrant 500 mg versus generic nonsteroidal aromatase inhibitors in patients with advanced breast cancer in the United Kingdom.

OBJECTIVE

The goal of this study was to examine the cost-effectiveness of fulvestrant 500 mg for the treatment of first progression or recurrence of advanced breast cancer in postmenopausal patients compared with generic nonsteroidal aromatase inhibitors (anastrozole and letrozole) in the United Kingdom.

METHODS

A cost-utility model based on a time-in-state approach was used. Clinical effectiveness estimates used in the model were derived from a network meta-analysis for overall survival and serious adverse events. Overall survival was extrapolated by using a Weibull distribution, and progression-free survival (PFS) estimates were derived from a simultaneous network meta-analysis and extrapolation of PFS curves by using the log-normal distribution. Data on resource use, costs, and utilities were based on various sources, including expert opinion and published data. To explore uncertainty, 1-way and probability sensitivity analyses were conducted. The study was conducted from the perspective of the UK National Health Service, and costs are reported in 2010/2011 British pounds.

RESULTS

The base case incremental cost-effectiveness ratio (ICER) for fulvestrant 500 mg versus letrozole was £34,528, with incremental costs of £14,383 and an incremental quality-adjusted life-year (QALY) of 0.417. Extended dominance occurred for anastrozole because the ICER for anastrozole versus letrozole was higher than the ICER for fulvestrant 500 mg versus anastrozole. Based on the probability sensitivity analyses, the probability that fulvestrant 500 mg was the most cost-effective treatment option was 3%, 20%, and 53% at a willingness-to-pay threshold of £20,000, £30,000, and £40,000 per QALY, respectively. According to the 1-way sensitivity analyses, the PFS estimates were the key drivers of the model results.

CONCLUSIONS

Although fulvestrant 500 mg was found not to be a cost-effective option at a standard UK threshold of £20,000 to £30,000 per QALY, it may be relevant to apply a higher threshold due to the poor prognosis of patients with advanced breast cancer and the limited number of hormonal treatment options available for this stage of treatment. Certain subgroups may also benefit from fulvestrant as a treatment option; however, limited data are currently available to identify these subgroups.