The bone health agent Xgeva® (denusomab) appears to delay the time to cancer progression and improve survival among early stage breast cancer patients treated with aromatase inhibitors. Its use should be considered in all appropriate patients, according to investigators who presented results of a recent study at the 2015 San Antonio Breast Cancer Symposium (SABCS).
Hormone-positive (HR+) breast cancer refers to breast cancer that is stimulated to grow when exposed to the female hormones estrogen and/or progesterone. The majority of breast cancers are HR+, and an effective and standard therapeutic approach for the treatment of HR+ breast cancers is hormone therapy to block the cancer cells from being exposed to the hormones that cause their excessive growth.
A common place for breast cancer to spread is the bones, and researchers continue to evaluate whether bone strengthening agents used for the treatment of osteoporosis can have a positive effect on reducing the risk of breast cancer spreading to the bones.
Researchers recently conducted a clinical trial to evaluate the potential effects of Xgeva in women with early stage breast cancer treated with hormone therapy. Xgeva is a drug that targets a protein known as the RANK ligand, which regulates the activity of osteoclasts (cells that break down bone). Xgeva has been previously approved for the prevention of bone complications such as fracture in patients with bone metastases from solid (not blood-related) cancers, and it is approved by the FDA as treatment to increase bone mass in breast cancer patients being treated with aromatase agents for early breast cancer who are at a high risk for developing a bone fracture.
The current trial included 3,425 postmenopausal women with HR+ early stage breast cancer. They were all treated with endocrine therapy consisting of aromatase inhibitor and with either Xgeva or a placebo (inactive substitute) and directly compared. The study revealed that Xgeva improved disease-free survival by 1% after 3 years, 2% after 5 years, and 3% at 7 years.
Michael Gnant, MD, the lead author and presenter of the study, stated that despite Xgeva’s FDA approval for breast cancer patients receiving endocrine therapy who are at a high risk for a fracture, “in most healthcare environments, it is only used for patients with established osteoporosis. Our new data suggest that this treatment should be offered to all patients with hormone receptor-positive breast cancer who are receiving adjuvant aromatase inhibitor therapy, irrespective of their bone health.” Further analyses will determine if Xgeva might actually make a difference in overall survival among this group of patients.
Reference: Gnant M, Pfeiler G, Dubsky PC, et al. The impact of adjuvant Xgeva on disease-free survival: Results from 3,425 postmenopausal patients of the ABCSG-18 trial. Proceedings from the 2015 annual meeting of the San Antonio Breast Cancer Symposium. Abstract S2-02.