FDA Approves Faslodex Monotherapy in HR+, HER2– Advanced Breast Cancer

Approval supports initial use in patients not previously treated with endocrine therapy

Fulvestrant (Faslodex, AstraZeneca) 500 mg has received FDA approval as monotherapy for expanded use in women with hormone-receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER–) advanced breast cancer who have gone through menopause and have not received previous endocrine therapy.

The FDA approval is based on pivotal data from the phase 3 FALCON trial, which were published in the November 2016 issue of The Lancet.

 “This study provides evidence that using fulvestrant as the first option for previously untreated hormone receptor-positive advanced breast cancer will prolong the time before the disease advances and alternative therapies are required,” said Matthew Ellis, MD, PhD, Director of the Lester and Sue Smith Breast Center, part of the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine.

The FALCON trial was designed to demonstrate superiority and included 462 postmenopausal women with HR+ metastatic or locally advanced breast cancer. The results showed a statistically significant increase in investigator-assessed median progression-free survival (PFS), representing a 20% reduction in the risk of disease progression or death determined by RECIST. Median PFS was 16.6 months in patients who received fulvestrant, compared to 13.8 months in patients receiving the aromatase inhibitor anastrozole (Arimidex, AstraZeneca) 1 mg (hazard ratio, 0.797; 95% confidence interval, 0.637–0.999; P = 0.049).

Fulvestrant is a hormonal therapy that targets the estrogen receptor (ER), which can influence the growth of HR+ metastatic breast cancer (MBC), and helps to slow cancer growth by blocking the ER and targeting it for degradation.

First approved in 2002, fulvestrant has been used as a monotherapy for the treatment of postmenopausal women with HR+ MBC whose cancer has progressed following prior antiestrogen therapy. In 2016, fulvestrant was approved by the FDA in combination with palbociclib, for the treatment of women with HR+, HER2– advanced or MBC, whose cancer has progressed after endocrine therapy.

Source: AstraZeneca; August 28, 2017.