In June the FDA approved denosumab (Prolia^TM), a twice-yearly treatment for patients at high risk for osteoporosis and fractures.  When Prolia was approved, Amgen the manufacturer, had hopes to also achieve this drugs approval for treatment in cancer patients at risk for bone fractures.  This week the Food and Drug Administration approved this treatment to reduce fractures and surgery in cancer patients with solid tumors that have spread to the bone. 

This new indication of denosumab is called Xgeva^TM, and is "indicated for the prevention of skeletal-related events in patients with bone metastases from solid tumors.  Xgeva is not indicated for the prevention of skeletal-related events in patients with multiple Myeloma (Xgeva Prescribing Information 2010)."

When cancer spreads to the bone this stimulates the production of a protein called RANK Ligand, which causes destruction of the bone.  Xgeva inhibits the production of RANK Ligand minimizing bone loss and fractures.  According to the Journal of Cancer in 2000, patients have malignant cells that spread to the bone 65-75% of the time.  When malignant cells transfer to the bone, symptoms may include: pain, swelling, and fractures.  Treatment options for these symptoms are: radiation, chemotherapy or amputation.

If you are considering this treatment, Amgen provides the following information on this drug.

Dosing For Xgeva

Xgeva is given in a fixed dose of 120 mg/mL every 4 weeks for treatment in cancer patients.  Prolia used for osteoporosis, is dosed at 60 mg/mL twice yearly.  This medication is injected into the thigh, upper arm or stomach, and can be done at your doctors' office.

Common Serious Side Effects

• Low serum calcium (hypocalcemia)
• Osteonecrosis of the jaw
• Dyspnea (difficulty in breathing)

Most Common Side Effects

• Fatigue
• Hypophosphatemia (low serum phosphate)
• Nausea

Precautions

Patients receiving Xgeva should have a creatinine clearance test to determine any existing problems with renal function.  Creatininie clearance results of ≤ 30 mL/min or on dialysis are at greater risk of severe hypocalcemia than those patients with normal testing scores.  No studies have been done on patients with a creatinine clearance of less than 30 mL/min or on those receiving dialysis.  If you have a test result of less than 30 mL/min, be sure to discuss this issue with your prescribing physician before administration of this medication.

Fracture Results

"One of these studies, submitted to the FDA, showed denosumab delayed broken bones and complications 20.7 months, or three months longer than Zometa in 1,901 prostate cancer patients whose tumors had spread to their bones. In another study of 2,046 breast cancer patients, denosumab delayed fractures or complications longer than Zometa, Perlmutter said."

"Denosumab also kept fractures at bay longer than Zometa in patients with a variety of other tumor types, although the difference wasn't statistically significant, Perlmutter said. For patients with multiple myeloma, Zometa outperformed denosumab. While the drug wasn't approved yesterday for myeloma, Amgen is starting a new study of patients with that condition."