New Drug Helps Spotlight Skeletal-Related Events

Stefan Glück, MD, PhD

Faced with substantial numbers of advanced cancer patients who suffer from bone metastases, the oncology community is paying fresh attention to the often painful skeletal-related events (SREs) that can result.

In recent months, a new drug, denosumab (Xgeva), has been launched, prompting the issuance of 2 sets of updated clinical practice guidelines concerning management of such patients.

Stefan Glück, MD, PhD, believes that although the incidence of bone metastases is widespread, the development occurs early enough in the disease progression that these patients could benefit significantly from therapy. Glück is assistant director of the Sylvester Comprehensive Cancer Center and associate chief of the Division of Hematology/Oncology at the University of Miami, Florida.

“They have only a short time to live, so every single day without such an event counts,” Glück said during a continuing medical education session at the Miami Breast Cancer Conference, held March 9-12 in Florida.

For late-stage patients, Glück said the rates of cancer metastasizing to the bone are 73% in breast cancer, 68% in prostate cancer, and 36% in lung cancer. SREs can include fracture, radiation to the bone, surgery to the bone, or spinal cord compression.

This illustration from Amgen depicts the cycle of bone destruction.

Glück, however, noted that bone metastases “occur quite early in the lifecycle of metastatic disease”; that is, at approximately 7 months in advanced breast cancer, 10.7 months in prostate cancer, and 5.2 months in lung cancer. With treatment, Glück said, the quality of life for late-stage patients can improve for much of their remaining lifespan.

In November, the FDA approved Xgeva for the prevention of SREs in patients with bone metastases from solid tumors (but not in multiple myeloma or other blood cancers). The agency said Xgeva, a monoclonal antibody that inhibits RANK ligand from promoting osteoclasts, was superior to zoledronic acid (Zometa) in delaying SREs in breast and prostate cancers, while the 2 drugs showed similar results in other solid tumors.

The most serious adverse effects associated with Xgeva were hypocalcemia and osteonecrosis of the jaw. Researchers say there is a lower risk of renal toxicity with Xgeva than zoledronic acid, which is a bisphosphonate.

In March, the National Comprehensive Cancer Network revised its guidelines to include Xgeva as an option for the prevention of SREs. In February, the American Society of Clinical Oncology said only patients who have developed bone metastases should be treated with such therapies and that there is insufficient evidence to demonstrate greater efficacy of 1 bone-modifying agent over another.

Glück’s presentation was sponsored by Amgen Inc, which manufactures Xgeva.