When Is It Appropriate to Discontinue Bisphosphonates?

Ibandronate sodium is one bisphosphonate used to inhibit osteoclast-mediated bone resorption.
DR P. MARAZZI / sciencesource.com

CHICAGO—A 75-year-old woman with low bone density, who has had a fracture and has other risk factors for fracture, is treated with the bisphosphonate alendronate. After five years on the drug she comes back, wondering: Should I stop taking the drug?

She’s had no additional fractures. Her bone density has improved, but her lumbar spine T score is still a bit above the treatment threshold. Her turnover markers are both low, consistent with the effects of the bisphosphonate treatment.

“Like many [osteoporosis patients], she’s worried about the side effects of her medicine,” said Kenneth Saag, MD, MSc, professor of medicine at the University of Alabama School of Medicine, who presented the case at the ACR’s State-of-the-Art Clinical Symposium in April.

It’s difficult to know just what to do in these scenarios, Dr. Saag said. It’s “become the most contentious topic in the bone field—how long to treat, and who should we consider [giving] a break from therapy?”

Calling this a “crisis,” Dr. Saag described how bisphosphonate use has been declining at a fast rate—appropriately in some cases, but other patients have simply stopped the drug without talking to a doctor.

“We have a 50% decline in our use of bisphosphonates from when it peaked in the mid-2000s,” he said.¹ After a fracture, only 20% of people are identified and treated—and that number is declining.²

At the same time, what had been a decline in hip fracture rate has begun to plateau.

The potential opportunity for a drug holiday in some patients is clear, Dr. Saag said. Bisphosphonates bind to bone, and when a patient stops using them after 10 years of treatment, they lose an estimated 2.5 mg per day.

“This is not like many drugs we use,” he said.

A long-term extension of a fracture intervention trial found that those rerandomized to five more years of alendronate treatment or five years of placebo showed maintenance of bone density and very similar fracture risks for the two groups.³

But other analyses have found that the risk of benefit in terms of hip and vertebral fracture prevention tends to far outweigh the risk of an atypical fracture brought about the drug. The risk increases with longer duration of use.

Dr. Saag emphasized that although a drug holiday may be a good idea for some patients on bisphosphonates, other drugs should not be considered for a holiday.

The U.S. Food & Drug Administration has issued guidance, saying that although the optimal duration isn’t known, discontinuation should be considered after three to five years for patients with a low fracture risk.