CancerConnect News: Faslodex® (fulvestrant) at a 500-mg dose has been demonstrated to be superior to Arimidex® (anastrozole) as first-line therapy for advanced hormone receptor–positive breast cancer in the phase II FIRST study.1 Both overall survival and time to cancer progression were significantly better with Faslodex® than with the current standard of care, Arimidex®.
Each year roughly 200,000 U.S. women are diagnosed with breast cancer. Many of these breast cancers will be hormone receptor-positive, meaning that they are stimulated to grow by the circulating female hormones estrogen and/or progesterone. Treatment of hormone receptor-positive breast cancer often involves hormonal therapies that suppress or block the action of estrogen.
Faslodex® is a type of hormonal therapy known as an estrogen receptor antagonist which blocks the actions of estrogen. It’s used for the treatment of metastatic, hormone receptor-positive breast cancer in postmenopausal women who experience cancer progression or recurrence after prior hormone therapy. Until recently, a standard dose of Faslodex was 250 mg.
In order to assess the effects of a higher dose of Faslodex, researchers first conducted a Phase III clinical trial known as CONFIRM (Comparison of Faslodex in Recurrent or Metastatic breast cancer). The study compared the 250 mg dose of Faslodex to a 500 mg dose. Faslodex 500mg was associated with a 19 percent reduction in risk of death and a 4.1-month improvement in median overall survival compared with Faslodex® 250mg.
In the current clinical trial, Faslodex® 500 mg was compared with Arimidex® as initial treatment in 205 women with advanced or metastatic breast cancer. The initial clinical benefit rate at 6 months was 72.5% for Faslodex® and 67% for Arimidex® demonstrating that Faslodex® at the 500-mg dose was at least as effective as Arimidex®.
Faslodex® however was found to have improved overall survival and delayed the time to cancer progression compared to Arimidex®. The median time to disease progression was 23.4 months with Faslodex® compared to 13 months for Arimidex®.
- Robertson JFR, Llombart-Cussac A, Felti D, et al: Fulvestrant 500 mg versus anastrozole as first-line treatment for advanced breast cancer: Overall survival from the phase II ‘FIRST’ study. 2014 San Antonio Breast Cancer Symposium.Abstract S6-04. Presented December 12, 2014.
- Di Leo A, Jerusalem G, Petruzelka L, et al. Final overall survival: Fulvestrant 500mg vs 250mg in the randomized CONFIRM trial. Journal of the National Cancer Institute. Published early online December 7, 2013. doi: 10.1093/jnci/djt337.