A combination of two AstraZeneca Plc drugs helped post-menopausal women with late-stage hormone-related breast cancer live longer and without the disease progressing compared with those taking just one of the drugs, a new study found.
The trial followed 694 patients who took either the combination of anastrozole and fulvestrant, also known by the brand names Arimidex and Faslodex respectively, or anastrozole alone. Their cancers were either estrogen-receptor positive or progesterone-receptor positive or both and hadn’t previously been treated with chemotherapy, immunotherapy or hormone therapy to stop the spread of disease, according to the study published in the Aug. 2 edition of the New England Journal of Medicine.
Patients who took the combination therapy had a median of 15 months without the disease progressing, while the median for those who took anastrozole alone was 13.5 months, the study found. Those in the combination group also lived six months longer than the control group, a benefit not seen in trials in recent years, Rita Mehta, lead investigator of the trial and an associate professor of medicine at University of California in Irvine, said in an interview.
“Six months means a lot to a patient,” she said. “It could be a graduation for a grandson or a new baby being born.”
She is prescribing the combination for her patients and said it should be the standard care in future.
Patients who hadn’t previously taken the hormone therapy tamoxifen and were assigned to the combination group saw a greater benefit than those who had, though the difference wasn’t statistically significant, the study found.
Both groups had mild to moderate side effects such as joint pain and hot flashes, and the rate was higher in the combination group though not statistically significant, the authors said.
The study was designed and conducted by Southwest Oncology Group and funded by the National Cancer Institute. AstraZeneca provided drugs for the trial at no cost.
Arimidex and Faslodex generated $756 million and $546 million in sales for AstraZeneca last year respectively. The company will evaluate the data and has not made a decision about pursuing a label change for Faslodex to be used in combination with Arimidex for this group of patients, said Sarah Lindgreen, a spokeswoman for AstraZeneca. Arimidex faces generic competition while Faslodex has been on the market in the U.S. since 2002.
AstraZeneca conducted a similar study three years ago with fewer patients and saw no statistical benefit between the two groups, according to the report. Most of the patients in that trial had been treated previously with hormone therapy.
Faslodex is being tested in late-stage clinical trials as a first-line treatment for advanced hormone-related breast cancer. If successful, the company plans to file for approval in the U.S. and Europe in 2016.