Medications called osteoclast inhibitors are the most common treatment for bone metastases.
Osteoclasts are bone cells that break down bone tissue. Osteoclast inhibitors interfere with the activity of osteoclasts. These medications can delay skeletal-related events (SREs) in the bone (such as fractures or spinal cord compression) while making the bones stronger. The medications can work in different ways, but they have similar effects.
Xgeva (chemical name: denosumab) is given monthly as an injection (a shot) under the skin.
Zometa (chemical name: zoledronic acid) is a type of medicine known as a bisphosphonate. Zometa requires an intravenous, or IV, drip every 1-3 months.
There are some differences between Xgeva and Zometa:
- Effectiveness: Xgeva is slightly more effective than Zometa at reducing the risk of complications from bone metastasis.
- Treatment timing and frequency: Xgeva can be given more quickly than Zometa since it’s a single injection (shot), but it must be given once a month. Zometa infusion takes more time, but it can be given less frequently. (Research on the timing and frequency of these medications is ongoing, so be sure to check with your doctor about how often they need to be taken.)
- Cost: A generic version of Zometa is available, so that might make a difference in terms of insurance coverage. If Zometa isn’t available, another bisphosphonate called Aredia (chemical name: pamidronate) can also be used.
Still, both Xgeva and Zometa are good for:
- relieving bone pain
- lowering the risk of osteoporosis (weakened bones)
- lowering the risk of spinal cord compression
- lowering the risk of breaking a bone weakened by the tumor
- lowering high levels of calcium in the blood
Before starting any bone-targeted therapy, your doctor should make sure your levels of calcium and Vitamin D aren’t too low. If so, they should be corrected before you begin the medication. You also may need to take supplements while you’re taking the medication.
Xgeva and Zometa also are associated with a rare side effect called osteonecrosis of the jaw, in which the cells in the jawbone start to die. Doctors often advise stopping the medication at least one month before having any dental work, whether a deep cleaning, filling, root canal, or something else. About 2 months after the procedure, you can start taking the medication again. Even if you’re not having dental work, let your dentist know you’re taking one of these medicines in case you develop problems that need immediate attention.
Kidney problems are another rare side effect of bisphosphonates such as Zometa and Aredia. Your doctor may decide to follow your kidney function over time.