A new option to fight bone loss

Annual IV therapy as effective as pills but may carry risk

May 03, 2007|By Chris Emery | Chris Emery,Sun reporter

Women who take pills to stave off osteoporosis could have an alternative treatment for thinning bones: a single, annual intravenous infusion that takes about 15 minutes in a doctor's office, according to a report released today.

The downside to the treatment is a slightly elevated risk of erratic heart rhythms, which have been linked to stroke.

But experts say the risk might be worth it for patients who can't tolerate pills or stick with an oral medication schedule to fight osteoporosis, which causes dangerous bone loss in millions of Americans, mostly women.

The study, reported in today's New England Journal of Medicine, found that an intravenous treatment with bisphosphonates -- a class of drugs typically taken in pill form -- was just as effective at reducing bone fractures in postmenopausal women with osteoporosis as oral treatments.

"It will expand options to treat women who cannot tolerate the oral forms of medicine," said Dr. Michele Bellantoni, an osteoporosis expert at the Johns Hopkins School of Medicine.

"But this should not replace the oral therapies," because of the heart risk, said Bellantoni, who was not involved in the study.

She also noted that the intravenous administration of the drug has not yet received federal approval for treating osteoporosis, although doctors already prescribe it in some cases.

The study was the first large clinical trial to test the effectiveness of the intravenous approach.

The National Institutes of Health estimates that 10 million Americans have osteoporosis, which is closely related to aging and makes its victims prone to bone fractures.

Many older men are also at risk for the disease, but 80 percent of its American victims are women, who tend to have thinner bones to start and lose bone mass rapidly after menopause because of hormonal changes.

Half of all women will suffer an osteoporosis-related bone fracture during their life -- most often of the hip, spine or wrist, according to the NIH.

In addition to advising patients to get more calcium and Vitamin D -- from supplements and dietary sources such as milk -- doctors often prescribe bisphosphonate drugs. Their trade names include Fosomax, Actonel and Boniva.

They work by blocking cells known as osteoclasts from nibbling away at bone to remove older bone cells, thus slowing the progression of bone loss. The pills -- often taken on a weekly basis -- are effective at preventing fractures, but many users have difficulty adhering to the drug regimen.

"Patients tend to stop taking the oral bisphosphonates," said Dr. Elizabeth Streeten, an endocrinologist at University of Maryland Medical Center.

Doctors noted patients' doubts about their effectiveness, unpleasant side effects such as acid reflux and the inconvenience involved in taking them.

One of Streeten's patients, Mabel Hemmes, 84, of Abingdon, said she recently switched to an intravenous bisphosphonate after giving up on an oral form. "You have to do it on an empty stomach," she said of her difficulties with the oral dose. "And you can't lie down for an hour."

She took the pills once a week for eight weeks but said they gave her intolerable acid reflux. "As soon as I stopped taking," she said, "I stopped having the reflux."

She went for her first dose of intravenous Zometa on Tuesday and said the entire doctor's visit took about an hour. Doctors hope patients such as Hemmes will be better at sticking with the intravenous treatments.

Even though the FDA hasn't specifically approved it, some doctors already prescribe the intravenous form for patients who find the oral medications especially difficult to take.

The intravenous technique has been approved for other ailments such as elevated blood calcium, a condition caused by certain cancers and thyroid problems.

But once a drug has been approved for any use, doctors can prescribe it "off label" if they believe it will be safe and effective.

Previous studies suggested that annual intravenous treatments were as effective as both pills and intravenous doses administered more frequently. The study published yesterday was designed to test that finding more rigorously.

Researchers randomly assigned 7,765 women ages 65 to 89 to receive either the annual dose of zoledronic acid -- a bisphosphonate sold as Reclast -- or a placebo. Novartis AG, the pharmaceutical company that developed the drug, paid for the study.

Women who took the bisphosphonate were 70 percent less at risk of spine fractures and 41 percent less at risk of hip fractures than a group of women who received a placebo.

Experts said the findings show the intravenous drugs are as effective as the oral medications.

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