Fulvestrant in hormone receptor-positive advanced breast cancer: A UK retrospective multicenter study.

Abstract

e12525 Background: Fulvestrant is a selective oestrogen receptor (ER) down regulator used to treat hormone receptor-positive advanced breast cancer in postmenopausal women. It is used at various time points in treatment. However, variations in funding across the UK limit universal patient access to fulvestrant. We sought to investigate its use and efficacy in UK clinical practice. Methods: Medical records of 458 patients with ER positive advanced breast cancer treated with fulvestrant between August 2011 and November 2018 at ten UK centres were reviewed. Demographics and treatment responses were recorded. Efficacy was analysed by progression free survival (PFS), clinical benefit rate (CBR) and overall survival (OS) with alive patients censored to December 2018. Results: Of the 445 patients with analysable data, median age was 70 (range 21-95). ECOG performance status was 0-1 in 70% (n = 285). Bone was most commonly involved (73%, n = 323), 307 (69%) had visceral involvement and 228 (51%) had nodal metastases. Both locally advanced and metastatic patients had received a median 2 (range 0 – 5 for all patients) prior endocrine therapy lines and 0 (range 0 – 6) prior chemotherapy lines. Fulvestrant was the first line treatment in 49 (11%). Median duration of fulvestrant use was 5 months (range 1-88). Overall, median PFS was 6 months. This increased to 7 months in absence of visceral disease, in whom 22% of patients achieved a prolonged PFS extending to 30 months. Fulvestrant produced a CBR of 41% in 355 patients assessed, of which 16% partially responded. First radiological assessment occurred at median 3 months (range 1-37). Progressive disease accounted for 82% of discontinuation compared to 4% owing solely to adverse events in 341 assessed patients. Median OS for the whole cohort was 23 months. Conclusions: This is one of the largest studied patient cohorts treated with fulvestrant. This heavily pre-treated population reflects real life fulvestrant use. Reassuringly the results confirm its clinical benefit in maintaining disease response. Given its potential synergistic action with other systemic agents, fair access to this highly active drug for all patients is as important now as ever before.