Economic Evaluation of Fulvestrant 500 mg Compared to Generic Aromatase Inhibitors in Patients with Advanced Breast Cancer in Sweden

Objectives In Sweden, breast cancer (BC) represents 30% of newly diagnosed cancers and is the most common cancer in women. For hormone-dependent BC, endocrine therapies varying in efficacy and price are available. The aim of this study is to assess the cost effectiveness of fulvestrant 500 mg as a second-line hormonal therapy for postmenopausal women with estrogen receptor-positive metastatic or locally advanced BC versus letrozole, anastrozole, and exemestane in Sweden. Methods A three-state (pre-progression, post-progression, and death) partitioned-survival model was used to estimate progression-free (PFS) and overall survival (OS) by extrapolating trial results beyond the trial period to capture costs and benefits over a lifetime perspective. The comparative effectiveness was sourced from a network meta-analysis. The evaluation was conducted from a Swedish national payer perspective; costs, resource use, and quality of life were based on published sources and expert opinion. Results Compared to anastrozole, letrozole, and exemestane the incremental cost-effectiveness ratios (ICERs) were €33,808, €33,883, and €49,225 per QALY with incremental costs of €13,283, €14,986, and €13,862, and incremental QALYs of 0.393, 0.442, and 0.282, respectively. Incremental cost per life-year (LY) gained €21,312 (incremental LY of 0.623), €20,338 (incremental LY of 0.737), and €27,854 (incremental LY of 0.498) for respective comparators. Applying the upper and lower credible intervals for PFS/OS from the meta-analysis had the greatest effect on the ICER in the sensitivity analysis. The results were relatively stable when varying other parameters. Conclusions Our results indicate that fulvestrant 500 mg may be a cost-effective alternative to aromatase inhibitors at a threshold of €100,000/QALY.