Cost Effectiveness of Fulvestrant 500 Mg in Endocrine Therapy-Naïve Women with Hormone Receptor-Positive Advanced Breast Cancer in The UK

OBJECTIVES: Fulvestrant is approved for the treatment of hormone receptor (HR)-positive advanced breast cancer (ABC) after progression on anti-estrogen therapy, and in combination with palbociclib, for HR-positive, human epidermal growth factor receptor 2 (HER2)-negative ABC after disease progression on endocrine therapy. This cost-effectiveness analysis evaluated fulvestrant 500 mg versus comparators (anastrozole, letrozole, tamoxifen, exemestane, palbociclib+letrozole) in endocrine therapy-naive patients with HR-positive, HER2-negative ABC. METHODS: A three-health-state partitioned survival model from the National Health Service and personal social services perspective was developed. Survival, response and adverse event (AE) data for fulvestrant and anastrozole were derived from the Phase 3 FALCON study (NCT01602380) and the Phase 2 FIRST study (NCT00274469); relative comparator data were derived from systematic literature reviews and network metaanalyses. Costs included drug acquisition, administration, disease management (progression-free, progressed disease, end-of-life), management of grade ≥3 AEs, and subsequent second- and third-line treatments (£UK;2016). Base-case health-state utility values were derived from FALCON (mixed model repeated measures analysis); scenario analysis utility values were based on FALCON and published literature. The model also considered utility decrements for AEs from published sources. RESULTS: Across a 30-year time horizon, incremental costs for fulvestrant versus anastrozole, letrozole, exemestane, tamoxifen or palbociclib+letrozole were £19,039, £23,317, £21,232, £17,205 and -£120,658, respectively. Incremental quality-adjusted life-years (QALYs) were 0.56, 0.77, 0.87, 0.76 and 0.09, respectively. This led to incremental cost-effectiveness ratios of £34,194, £30,139, £24,472 and £22,495 per QALY versus anastrozole, letrozole, exemestane and tamoxifen, respectively, while fulvestrant dominated palbociclib+letrozole. Fulvestrant was associated with longer time to disease progression and time alive versus all comparators except palbociclib+letrozole, which had greater time to disease progression. CONCLUSIONS: Results suggest fulvestrant 500 mg is cost effective versus other endocrine monotherapies, and dominant versus palbociclib+letrozole, in patients with endocrine therapy-naive, HR-positive, HER2-negative ABC, with clinically significant overall survival gains and maintained quality of life.