Additional results from a Phase 3 study show that Xgeva may be more effective than Zometa in treating bone disease in multiple myeloma patients. Specifically, Xgeva was better than Zometa in reducing bone fractures, limiting the need for bone radiation treatment, and preventing the worsening of pain in cancer patients with bone disease.

Despite these findings, physicians are likely to remain cautious about treating myeloma patients with Xgeva, as there are concerns about the drug's safety when used in myeloma patients.

Bone disease is a common complication of multiple myeloma. Bone-destroying cells are more active in the bones of myeloma patients than bone-forming cells, which leads to bone destruction.

To slow down and prevent bone destruction, myeloma patients typically receive treatment with drugs known as bisphosphonates, which reduce the activity of the body's bone-destroying cells. The most commonly prescribed bisphosphonates in multiple myeloma are Zometa ^[1] (zoledronic acid) and Aredia ^[2] (pamidronate).

Xgeva ^[3] (denosumab) also prevents bone removal and degradation by reducing the activity of the body's bone-destroying cells.  However, Xgeva is an antibody, not a bisphosphonate, and it interferes with the activity of the body's bone-destroying cells in a way that is different from bisphosphonates.

Xgeva was first marketed by Amgen (NASDAQ: AMGN) at lower doses under the brand name Prolia for the treatment of postmenopausal women with osteoporosis and a high risk of bone fractures.

It has since been investigated for the treatment of bone disease in solid tumors and multiple myeloma.

Several Phase 3 trials showed Xgeva may be at least as effective as Zometa in preventing bone disease in cancer patients. Based on the results of these trials, Xgeva was approved by the U.S. Food and Drug Administration in 2010 for the treatment of bone disease in patients with solid tumors.

Xgeva was not, however, approved for patients with multiple myeloma because twice as many myeloma patients treated with Xgeva died as compared to those treated with Zometa (see related Beacon ^[4] news).

However, Xgeva continues to be investigated as a potential treatment for bone disease in myeloma.

Researchers recently published additional findings from one of the Phase 3 trials comparing Xgeva and Zometa.  These additional findings include the effect of treatment on the need for bone radiation treatment, pain management, and quality of life.

The Phase 3 trial included 1,776 patients, who were randomly assigned to receive Xgeva, Zometa, or a placebo. Approximately 10 percent of the study participants had multiple myeloma. All other participants had solid tumors.  However, patients with breast or prostate cancer were not included in the study.

Between 64 percent and 66 percent of patients were taking painkillers prior to the clinical trial.

The results showed that Xgeva decreased the need for bone radiation treatment by 22 percent compared to Zometa.  Radiation is often used to reduce the pain associated with bone disease.

Furthermore, fewer patients receiving Xgeva (31 percent) experienced one or more bone fractures, spinal cord compressions, or other bone-related complications, compared to patients receiving Zometa (36 percent).

Xgeva was also more effective than Zometa in delaying pain associated with bone disease. Patients treated with Xgeva had a median of 5.6 months before reporting worsening of clinically significant pain, compared to 4.7 months for patients treated with Zometa.

In patients with no or mild pain prior to the trial, Xgeva was more effective than Zometa in delaying the time to moderate-to-severe-pain (4.7 months versus 3.4 months, respectively).

Health-related quality of life was similar in both treatment groups. However, significantly more patients receiving Zometa (27 percent relative increase) shifted to stronger painkillers over a period of 11 months than patients receiving Xgeva.

Amgen is currently conducting a Phase 3 clinical trial ^[5] comparing the efficacy and safety and Xgeva and Zometa specifically in multiple myeloma patients. The trial is still recruiting participants.

For more information, please refer to the study in the journal Annals of Oncology ^[6] (abstract). For more information regarding all ongoing trials involving Xgeva in multiple myeloma, please see the U.S. Clinical Trials Registry ^[7].