Denosumab superior to zoledronic acid in delaying skeletal-related side effects in breast cancer patients

Key Points

A newly approved drug, denosumab (Xgeva, Amgen), delays skeletal-related side effects for 5 months longer compared to zoledronic acid (Zometa and Reclast, Novartis) in patients with breast cancer and bone metastases, according to phase 3 trial results presented at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium, San Antonio, Texas.

The research, headed by Alison T. Stopeck, MD, associate professor of medicine and director of the Clinical Breast Cancer Program at the University of Arizona's Arizona Cancer Center, randomly assigned 2,046 patients with advanced breast cancer to receive either 120 mg of subcutaneous denosumab or 4 mg of intravenous zoledronic acid every 4 weeks. Results from the study demonstrated that denosumab was better at delaying the time to first on-study, skeletal-related event by 18% and the time to first and subsequent event by 22%. The median time to first on-study, skeletal-related event was 5 months longer for the denosumab group compared to the zoledronic acid group.

Denosumab is more efficacious and better tolerated by patients, Dr Stopeck said.

Overall survival and disease progression was similar for both groups. Rates of side effects were 96.2% for those taking denosumab and 97.4% for those taking zoledronic acid. Osteonecrosis of the jaw occurred in 2.5% of patients taking denosumab and 1.8% of those taking zoledronic acid.

FDA approved denosumab on Nov. 18, 2010, for the prevention of skeletal-related events in patients with bone metastases from solid tumors.