The U.S. Food and Drug Administration (FDA) has expanded the approval of Prolia® (denosumab) to include treatment of bone loss among breast cancer patients treated with aromatase inhibitor therapy and prostate cancer patients treated with androgen deprivation therapy for non-metastatic cancer. Treatment is intended to increase bone mass among patients at high risk of fracture.
Osteoporosis affects an estimated 10 million Americans over the age of 50. Each year, roughly 1.5 million Americans will experience an osteoporosis-related bone fracture. These fractures commonly involve the wrist, hip, or spine, but can affect any part of the body.
Bone loss accelerates as we age (with particularly rapid loss in women after menopause), but can also be caused by certain types of cancer treatment. Hormonal therapies such as aromatase inhibitors for breast cancer and androgen-deprivation therapy for prostate cancer, for example, are known to cause bone loss. Bone loss from cancer treatment tends to be more rapid and severe than the bone loss that occurs naturally with aging.
Prolia targets a protein known as the RANK ligand. This protein regulates the activity of osteoclasts (cells that break down bone). Prolia has been shown to reduce the risk of fractures in high-risk postmenopausal women with osteoporosis, and was approved for this purpose in 2010.
Studies have also now shown that Prolia is effective against cancer treatment-induced bone loss. In a study of men undergoing androgen-deprivation therapy for non-metastatic prostate cancer, those who received Prolia were 62% less likely to develop a new vertebral fracture than those who received a placebo. Prolia has also been found to improve or maintain bone density among women undergoing aromatase inhibitor treatment for breast cancer. The most common side effects of Prolia were joint and back pain.
Prolia is the first drug approved for cancer treatment-induced bone loss.
 U.S. Department of Health and Human Services. Bone Health and Osteoporosis: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Office of the Surgeon General, 2004.
 Smith MR, Egerdie B, Hernandez Toriz N et al. Denosumab in men receiving androgen-deprivation therapy for prostate cancer. New England Journal of Medicine. Early online publication August 11, 2009.
 Ellis GK, Bone HG, Chlebowski R et al. Randomized trial of denosumab in patients receiving adjuvant aromatase inhibitors for nonmetastatic breast cancer. Journal of Clinical Oncology. 2008;26:4875-4882.