The final results are in—and they show that 500 mg of Faslodex® (fulvestrant) provides a significant advantage in overall survival compared to 250 mg of the drug in postmenopausal women with locally advanced or metastatic estrogen receptor–positive breast cancer recurring or progressing after prior endocrine therapy. The results were published online in the Journal of the National Cancer Institute.

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—a type of hormonal therapy known as an estrogen receptor antagonist—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 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 among 736 women in 17 countries. Initial analysis of the study showed an improvement in progression-free survival. Now, the final analysis is in.

At the time of the final analysis, 75.3 percent of patients had died and the median overall survival was 26.4 months in the 500 mg group compared with 22.3 months in the 250 mg group.

There were no new safety concerns identified during the follow-up and no significant differences in the profiles of serious adverse events between the two groups.

The researchers concluded: “In patients with locally advanced or metastatic estrogen receptor–positive breast cancer, Faslodex 500mg is associated with a 19 percent reduction in risk of death and a 4.1-month difference in median overall survival compared with Faslodex 250mg.”


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

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