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Once-a-Year Osteoporosis Treatment on the Horizon

Recent study suggests that a 15-minute IV of zoledronic acid may deliver yearlong benefits

Annual injections of a medication for Paget’s disease greatly reduced older women’s risk for fractures, according to a report in the New England Journal of Medicine. The findings could open the door to U.S. Food and Drug Administration (FDA) approval of once-a-year zoledronic acid for the treatment of osteoporosis.

Zoledronic acid is a bisphosphonate – a drug that slows the body’s natural resorption of bone into the blood stream. Bisphosphonates are commonly used to prevent or treat osteoporosis and bone fractures. Osteoporosis primarily affects women in their postmenopausal years, although it can afflict men as well. As bones thin and become more fragile, they break more easily, causing severe disability and even death.

While many bisphosphonates – including the Fosamax®, Actonel® and Boniva® brands – are given via weekly or monthly oral medications, zoledronic acid is administered intravenously. And because it’s so potent, a single infusion may be sufficient for up to 12 months. (Boniva can also be administered intravenously, but must be given every three months.)

“With zoledronic acid, a 15-minute IV may give patients yearlong benefits,” says Nora Sandorfi, MD, a rheumatologist at Thomas Jefferson University Hospital and Assistant Professor of Medicine at Jefferson Medical College of Thomas Jefferson University.

An alternative to oral meds?
With traditional anti-resorptive medications, patients typically take a pill on a weekly or monthly basis. They must also comply with guidelines for taking these pills; for instance, patients must fast, sit and consume a full glass of water with the medication.

Dr. Sandorfi says that while most people who are actively treating their osteoporosis are willing to adhere to such requirements, there are patients who cannot or will not take the oral medications.

“For those individuals, zoledronic acid is a very attractive alternative,” Dr. Sandorfi says, adding that it’s also a good option for patients who likely have bone thinning or osteoporosis but don’t know it – and therefore aren’t doing anything about it

“There are significant numbers of elderly people who will break a bone and get treatment for that fracture, but never come to see a rheumatologist about treating their osteoporosis,” she explains.

“Zoledronic acid is a very potent medication that will allow us to treat osteoporosis in that population, helping to prevent future fractures. Just as important, it buys these individuals another full year to follow up with a DXA [Dual Energy X-ray Absorptiometry] scan to measure bone density.”

Success high; side effects need study
Funded by the medication’s maker, Novartis Pharma, the current study looks at how well annual injections do three years out. Almost 4,000 postmenopausal women were randomly assigned to receive a single 15-minute infusion of zoledronic acid or a placebo (inactive substance) at baseline, and then 12 months and 24 months later. Participants were followed out to the 36-month point.

Treatment with zoledronic acid reduced the risk of vertebral fractures by 70 percent (3.3 percent of women in the treatment arm and 10.9 percent of women in the placebo arm suffered such fractures) over three years, the team reported. It also reduced the risk of hip fracture by 41 percent (1.4 percent of women in the zoledronic acid group vs. 2.5 percent in the placebo arm).

Meanwhile, non-vertebral fractures, clinical fractures and clinical vertebral fractures were reduced by 25 percent, 33 percent and 77 percent, respectively. Women in the treatment arm also experienced significant improvement in bone mineral density and bone metabolism markers.

There was a slight downside to the injections: women in the zoledronic acid group experienced more incidents of an irregular heart rhythm called atrial fibrillation. Other side effects were similar in both groups.

Dr. Sandorfi says that while this potential side effect should always be in the physician’s mind when evaluating a patient for this treatment, it probably does not represent a major cause for concern.

She says the same is true of the recent concern about osteonecrosis, or “freezing up” of the jaw, due to oral bisphosphonates, such as Boniva and Fosamax.

“This zoledronic acid study examined 4,000 women from around the world, and there were no reports of osteonecrosis,” she notes. “It seems to be an issue only in patients who have a tumor in the jaw or who have had radiation to the jaw.”

Always consult a physician if you experience a fracture or if you suspect you may have bone loss.To schedule an appointment with a Jefferson physician, call 1-800-JEFF-NOW. Regardless of your needs, including location, types of insurance accepted, and particular expertise, JEFF NOW will help you find the doctor that’s right for you and get you an appointment quickly and easily.