Among patients with bone metastases from cancers other than breast cancer or prostate cancer, the investigational drug denosumab was as effective as Zometa® (zoledronic acid) at reducing the risk of bone complications such as fracture. The results of this Phase III clinical trial were made available in a press release from Amgen.

Denosumab is an investigational drug that targets a protein known as the RANK ligand. This protein regulates the activity of osteoclasts. 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. Among women with bone metastases from breast cancer, denosumab appears to be more effective than Zometa at reducing the risk of bone complications.[1]

To directly compare denosumab to Zometa among patients with bone metastases from cancers other than breast cancer or prostate cancer, researchers conducted a Phase III clinical trial among more than 1,700 patients.[2] Study participants were assigned to receive either denosumab or Zometa.

The objective of the study was to determine whether the occurrence “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.

The results indicated that denosumab and Zometa were similarly effective against bone complications. Overall survival and time to cancer progression were also similar in the two study groups.

Osteonecrosis of the jaw (ONJ)—an uncommon but serious condition involving death of bone in the jaw—occurred with similar frequency in the two study groups. Out of the more than 1,700 study participants, ONJ developed in ten patients treated with denosumab and 11 patients treated with Zometa.

Comments: The results of this study suggest that denosumab is as effective as Zometa in the management of patients with bone metastases from cancers other than prostate or breast cancer. Full results are expected to be presented at an upcoming medical meeting.

References:

[1] Amgen press release. Denosumab demonstrates superiority over Zometa in pivotal phase 3 head-to-head trial in breast cancer patients with bone metastases. Available at: http://wwwext.amgen.com/media/media_pr_detail.jsp?year=2009&releaseID=1305355 Accessed July 8, 2009.

[2] Amgen Press Release. Amgen announces positive top-line results for denosumab in trial for delay of skeletal related events in bone metastases patients compared to Zometa®. Available at: http://wwwext.amgen.com/media/media_pr_detail.jsp?year=2009&releaseID=1316081 Accessed August 5, 2009.