Advanced breast cancer is less common in pre-menopausal women than in older women, but the rate is increasing. Between 1976 and 2009, the incidence of advanced breast cancer in women between 25 and 39 years of age has increased by 2% each year. Unfortunately, it is the leading cause of cancer death in women between 20 and 59 years of age.
However, treatments are also rapidly improving. In particular, contemporary research often focuses on the use of combination therapies. Recently published results from the MONALEESA-7 trial has confirmed that adding the targeted enzyme inhibitor drug ribociclib to standard-of-care endocrine therapy can significantly improve outcomes in pre-menopausal women. In the trial, women who took the combination therapy had a 42-month survival rate of 70%, compared with a survival rate of 46% in those on the hormone therapy alone.
“This is the first study to show improved survival for any targeted therapy when used with endocrine therapy as a first-line treatment for advanced breast cancer,” said lead study author Dr. Sara Hurvitz, Director of the Breast Cancer Clinical Research Program at UCLA Jonsson Comprehensive Cancer Center in Los Angeles. “The use of ribociclib as a front-line therapy significantly prolonged overall survival, which is good news for women with this terrible disease.”
Ribociclib inhibits the activity of enzymes in the body that can promote cancer, known as cyclin-dependent 4/6 kinases (CDK 4/6). The study showed that the combination therapy was tolerated well in a group of 672 women, and improved survival outcomes.
Australian-based breast cancer researcher, Dr Theresa Hickey (University of Adelaide), welcomed the results of this study. Dr Hickey, who was not involved in the study, said, “Combination therapy for breast cancer is definitely a window to a future of improved survival and this study firmly opens that window for many women.”
The next step is to establish whether some groups of patients benefit more from the combination treatment. The research team will analyse the wealth of data from the MONALEESA-7 trial, and look at whether certain biomarkers can predict outcomes. In addition, ribociclib is also being investigated as a possible treatment in early breast cancer.