(RxWiki News) When breast cancer begins to spread to other organs, it's considered Stage IV. Two drugs currently being used to treat breast cancer have been found to work better together for the most serious form of the disease.
Two estrogen-blocking drugs given together instead of in order extends the lives of postmenopausal women with Stage IV breast cancer.
"Ask your oncologist about combination therapies."
A phase III trial found that giving the drugs - anastrozole (Arimidex) and fulvestrant (Faslodex) - together extended the lives of patients by about six months.
The multi-institutional study was led by Rita Mehta, MD, of the University of California, Irvine Medical Center.
"The combination offers a new standard for first-line treatment of postmenopausal women with hormone receptor-positive metastatic breast cancer," said Dr. Mehta.
"It has been many years since these patients have seen a new treatment that can significantly extend their overall survival time," said Dr. Mehta, who is an associate clinical professor of medicine with the Chao Family Comprehensive Cancer Center and an oncologist with UC Irvine's Breast Health Center.
Both drugs are in a class known as aromatase inhibitors. These medications block estrogen, which fuels the majority of breast cancers.
Arimidex is taken daily in pill form and Faslodex is given by injection. Typically, Arimidex is given initially, and then Faslodex is given after the disease progresses.
For the study, researchers worked with just over 700 postmenopausal women who had metastatic breast cancer that was hormone-receptor-positive.
The women were randomly assigned to receive either the standard sequential therapy - Arimidex and then Faslodex - or the two drugs at the same time.
Those who received the standard treatment lived a median of 41.3 months, while those who took the combination therapy lived a median of 47.7 months.
"This study is the first to show that combination hormonal therapy alone without chemotherapy improves survival in advanced breast cancer," said another lead author, Kathy Albain, MD, a breast cancer specialist at Loyola University Medical Center.
"This most likely will change the standard of care for how we treat these patients." Dr. Albain concluded.
Disease progression was also slowed by 1.5 months in the combination treatment group.
Adam Brufsky, MD, PhD, professor of medicine at the University of Pittsburgh School of Medicine, told dailyRx, "This may be a way forward, in that the combination of two effective drugs for metastatic breast cancer appears to have an additive if not a synergistic effect in this trial."
Side effects were similar for both groups, however the most serious adverse events, including one stroke and two pulmonary embolisms (blockage of lung artery) were seen in the combination therapy group.
The study was limited, according to the authors, by the fact that only half the standard dosage of fulvestrant was used in the trial.
The findings appear in the August 2 issue of The New England Journal of Medicine.
This study was funded by the National Cancer Institute; several authors disclosed having financial relationships with a number of different companies, including pharmaceutical manufacturers.