Among women with bone metastases from breast cancer, denosumab was more effective than Zometa® (zoledronic acid) at delaying or preventing bone complications such as fracture. The results of this Phase III clinical trial were presented at a major European cancer conference.
Metastatic cancer refers to cancer that has spread to distant sites in the body. Several types of cancer—including breast cancer—have a tendency to spread to the bone. Bone metastases can lead to serious problems such as fracture and spinal cord compression, and may require treatment with surgery or radiation therapy.
Bisphosphonate drugs such as Zometa are commonly used to reduce the risk of complications from bone metastases. Researchers continue, however, to explore new approaches to treatment.
Denosumab is an investigational drug that targets a protein known as the RANK ligand. This protein regulates the activity of osteoclasts (cells that break down bone). Denosumab has shown promising results in the management of patients with bone metastases as well as the management of bone loss due to cancer treatment.
To directly compare denosumab to Zometa among breast cancer patients with bone metastases, researchers conducted a Phase III clinical trial. The study enrolled more than 2,000 patients. Study participants were assigned to receive either denosumab or Zometa.
The objective of the study was to determine whether the occurrence of bone complications (“skeletal related events”) differed between the two study groups. The bone complications that were evaluated were fracture, radiation to the bone, surgery to the bone, and spinal cord compression.
- Patients treated with denosumab remained free of bone complications longer than patients treated with Zometa.
- Denosumab effectively delayed the worsening of bone pain.
- Overall survival and time to cancer progression were similar among patients treated with Zometa and patients treated with denosumab.
- Osteonecrosis of the jaw (an uncommon but serious side effect) occurred with similar frequency among patients treated with Zometa and patients treated with denosumab.
The results of this study suggest that denosumab may be more effective than Zometa at delaying or preventing skeletal complications in breast cancer patients with bone metastases.
Stopeck A, Body JJ, Fujiwara Y et al. Denosumab versus zoledronic acid for the treatment of breast cancer patients with bone metastases: results of a randomized phase 3 study. Presented at the Joint ECCO 15-34thESMO Multidisciplinary Congress. Berlin, Germany, September 20-24, 2009. Abstract 14LBA.