The Food and Drug Administration (FDA) has approved denosumab to help prevent bone damage in people with solid tumors, an abnormal mass that usually does not contain cysts or liquid areas, and bone metastases, cancer that has spread to the bone tissue.
Denosumab was originally approved under the name Prolia as an osteoporosis treatment for healthy postmenopausal women at high risk for fractures. In its new cancer treatment application it will be called Xgeva. The approval means doctors may prescribe Xgeva to women with metastatic breast cancer to the bones who are at risk for fracture.
Invasive cancer that has developed in one area of the body, called the primary site, can spread beyond the breast and into other parts of the body. This is a called metastasis. Bone is one of the more common areas where this can happen, and breast cancer spreads to the bone first in approximately 25 percent of cases.
Bone metastasis is one of the most frequent causes of pain from cancer, and when cancer spreads to the bone it makes the bone weaker and can even cause it to break. Both of these things—pain and bone weakness—can limit your ability to keep up with your usual activities and lifestyle. Taking steps to strengthen bone may have a positive impact on your quality of life, and supports you in your efforts to maintain your current lifestyle.
The current FDA approval is based on the results of three different trials, each comparing denosumab to zoledronic acid (Zometa). Denosumab works by blocking a specific protein that contributes to the break down of bone cells, which can lead to bone damage. Each of these three trials considers how denosumab affects bone metastases caused by different types cancer, and the second study focuses specifically on the treatment of bone metastases in women with advanced breast cancer. While these trials are ongoing, none is recruiting new participants.
In comparative clinical trials like these, participants are assigned to different groups or arms, where they receive different treatments. In the first arm of the breast cancer trial, participants are given a placebo or sugar pill—a substance that does not have medicine—and zoledronic acid. In the second arm, participants are given a placebo and denosumab, the medicine that is being tested in the trial. Incidents of bone damage for each of the two groups—referred to as “skeletal-related events” or SREs—are then compared. In all three trials denosumab was shown to be at least as effective as zoledronic acid in preventing bone-related problems.
What Does this Mean for Me?
Bone metastasis puts women with breast cancer at increased risk for bone damage and skeletal-related events, and it is estimated that more than 50 percent of people whose cancer has spread to the bone are affected by bone-related complications. These sorts of complications can compromise your overall quality of life by diminishing your capacity to pursue your interests. The approval of denosumab by the FDA as a means for slowing down the break down of bone cells and potentially preventing bone damage associated with bone metastases provides an opportunity for you and your treatment team to consider additional quality of life options.