CHICAGO --- For women suffering from stage-4 breast cancer, there is a new treatment plan that, according to a recent Northwestern Medicine clinical trial, is highly effective and has minimal toxicity. The treatment includes a drug recently approved by the U.S. Food and Drug Administration.

The study combined palbociclib and fulvestrant to treat women with recurrent metastatic (advanced) breast cancer who are resistant to standard endocrine therapy. Patients who were treated with the two drugs experienced significantly longer periods of progression-free survival than those who received a placebo-plus-fulvestrant treatment.

"This is a significant achievement because patients who fail to respond to endocrine therapy usually require chemotherapy for treatment with a compromise on quality of life," said first author Dr. Massimo Cristofanilli, professor of medicine at Northwestern University Feinberg School of Medicine and a Northwestern Medicine oncologist. "The current study provides an effective and less toxic option for the most common type of metastatic breast cancer."

"The patients in this study who received the combination treatment experienced a better quality of life than those who received the standard endocrine therapy. The study also included patients who received chemotherapy," said Cristofanilli, who is also the associate director for precision medicine and translational research at the Robert H. Lurie Comprehensive Cancer Center of Northwestern. This treatment, he said, also comes without chemotherapy's typical side effects, which may include complete hair loss and neuropathy, which is numbness or pain from nerve damage.

The study will be published in Lancet Oncology on March 2.

A woman's estrogen can sometimes fuel breast cancer, and endocrine therapy works to block the estrogen. The study focused on women who may have been previously resistant to endocrine treatment and had, in some cases, received chemotherapy. Additionally, this was the first time this combination of drugs had been tested in premenopausal women, who previously had very few treatment options.

Cristofanilli studied 521 women from 144 centers across 17 countries, 18 years and older, who had endocrine-resistant, hormone receptor-positive metastatic breast cancer. Over the 10-month, phase 3 clinical trial between 2013 and 2014, patients were randomly assigned to receive two drugs, palbociclib and fulvestrant, or a placebo and fulvestrant.

Patients who received the combined-drug treatment experienced, on average, 9.5 months of progression-free survival compared with 4.6 months for the control group, a difference of 4.9 months.

"For women living with breast cancer, prolonged disease control may translate into improved survival, and this is as close as we can get to a cure," Cristofanilli said. "For now, we are hoping to get to the point where breast cancer is a chronic disease that we can continue to treat for a long time, and this drug gives an important additional option for women with estrogen-positive metastatic breast cancer."

Source: Northwestern University