Real‐world effectiveness of fulvestrant monotherapy as first endocrine treatment in patients with metastatic breast cancer

Abstract

Fulvestrant monotherapy is approved for postmenopausal women with hormone receptor‐positive, metastatic breast cancer (MBC) who progressed following antiendocrine therapy, or those with hormone receptor‐positive, human epidermal receptor 2‐negative advanced breast cancer (BC) not previously treated with endocrine therapy (ET). However, real‐world data are lacking. Retrospective reviews of 10 United States community oncology practices identified patients diagnosed with MBC between 1 January 2011 and 31 December 2015 who received fulvestrant as the first ET, either as initial therapy for metastatic disease or after progression following one line of chemotherapy. Endpoints were progression‐free survival (PFS) and overall survival (OS). Patients were classified as ET‐naïve or by relapse status following adjuvant ET (“early” recurrence during or ≤12 months of completing adjuvant ET, or “late” >12 months after completing adjuvant ET). Outcomes were evaluated using Kaplan‐Meier methods. Among 121 patients, median PFS (95% confidence interval) was 8.3 months (4.8‐12.3) for early relapse, 15.4 months (10.2‐21.2) for late relapse, and 18.7 months (10.1‐20.8) among ET‐naïve patients (P = .018). Median OS was 39.8 months (25.0‐55.1) for early relapse and 61.4 months (47.1‐61.4) for late relapse, but was not reached (NR; 55.6–NR) for ET‐naïve patients (P = .002). Fulvestrant monotherapy as the first ET after MBC diagnosis demonstrates PFS comparable to clinical study results; outcomes appeared better in patients without prior ET exposure and in patients with disease recurrence >12 months following adjuvant ET. These findings support fulvestrant monotherapy in patients with hormone receptor‐positive MBC.

Efficacy of Fulvestrant in Women with Hormone-Resistant Metastatic Breast Cancer (mBC): A Canadian Province Experience

“…It is important to note that patients with primary versus secondary endocrine-resistant disease did not have significant differences in TTP or OS. Other studies have demonstrated a decreased response to fulvestrant based on previous endocrine insensitivity [18,22]. This study also shows that patients taking chemotherapy after discontinuing fulvestrant had a significantly longer median overall survival of 34 months, compared to 8 months in patients who did not receive chemotherapy, showing a 68% relative reduction in mortality.…”

Efficacy and Safety of Fulvestrant 500mg in Hormone-receptor Positive Human Epidermal Receptor 2 Negative Advanced Breast Cancer: A Real-world Study in China

“…To our knowledge, Fulvestrant is recommended to be the standard option for first-line endocrine therapy in HR-positive advanced breast cancer patients. The outcome of phase II FIRST study (CBR: 72.5%; median PFS: 23.4 months) [20,30] and phase III FALCON study (CBR:78%; median PFS: 16.6 months) 24 implied that Fulverstrant was more effective than third-generation aromatase inhibitors in patients without previous endocrine therapy. The real-world study from China and US reported that the PFS of Fulvestrant in first-line users were 15.67 months and 12.2 months respectively [24,31] .…”

“…The outcome of phase II FIRST study (CBR: 72.5%; median PFS: 23.4 months) 20 , 30 and phase III FALCON study (CBR:78%; median PFS: 16.6 months) 24 implied that Fulverstrant was more effective than third-generation aromatase inhibitors in patients without previous endocrine therapy. The real-world study from China and US reported that the PFS of Fulvestrant in first-line users were 15.67 months and 12.2 months respectively 24 , 31 . However, in our study, only 17.5% (53/303) patients received Fulvestrant as the first-line treatment.…”

“…Despite the substantial evidence suggesting the efficacy of Fulvestrant by randomized control trials (RCTs), there is paucity of available literature regarding the safety and effectiveness of Fulvestrant 500mg in the real-world settings of patients with advanced breast cancer. The study population of current real-world data, which is different from those Chinese patients with characteristic of younger age of diagnosis, higher proportion of premenopausal and primary stage IV breast cancer, cannot well represent the actual situation of China [23][24][25][26] . In addition, the research concerning Chinese breast cancer population has the limitation of small sample size [27] .…”

A role for fulvestrant monotherapy in the first‐line treatment of ER+ metastatic breast cancer?

“…The study by Skinner et al evaluates the real‐world effectiveness of fulvestrant monotherapy as first endocrine treatment in 121 patients with ER + MBC . Patients from community practices who received fulvestrant as the first endocrine therapy (either as first‐line treatment or after one line of chemotherapy) were included.…”