Conference Coverage

Take drug, patient-level factors into account for when to end antiresorptive therapy



The optimal duration of antiresorptive treatment for osteoporosis depends on the agent used and on individual patient factors, but questions remain in this evolving area of research, according to an overview presented by Marcy B. Bolster, MD.

Marcy B. Bolster, MD, associate professor of medicine at Havard Medical School in Boston

Dr. Marcy B. Bolster

Recently published studies may help guide decisions about initiating and discontinuing treatment with bisphosphonates or denosumab (Prolia), the antiresorptive therapies. Understanding the ideal duration of bisphosphonate drug holidays “is a work in progress,” Dr. Bolster, from Harvard Medical School in Boston, said at the annual Perspectives in Rheumatic Diseases held by Global Academy for Medical Education.

No holiday with denosumab

Data indicate that twice yearly denosumab remains safe at 10 years, but studies have found a rapid loss of bone mineral density and an increased risk for vertebral fractures after treatment is discontinued (J Bone Miner Res. 2018 Feb;33[2]:190-8).

“Therefore, it is not appropriate for denosumab to be utilized with a drug holiday. If a patient is placed on denosumab, then consideration needs to be given for what to follow the course of denosumab,” Dr. Bolster said. “It is important to review with our patients the essential scheduled dosing of every 6 months, that the patient should not miss doses, and that we are not going to be able to initiate a drug holiday without starting another medicine.”

Patients likely to require hospitalization may not be good candidates for denosumab therapy because they may not be able to adhere to the dosing regimen, she said.

Denosumab vs. bisphosphonates: Real-world data

Trials have found greater increases in bone mineral density with denosumab, compared with the bisphosphonate drug alendronate, but that finding does not necessarily equate with reduced fracture risk, Dr. Bolster said. A recent population-based study examined fracture risk in approximately 92,000 people over age 50 years. Most were women, and their mean age was 71 years (JAMA Netw Open. 2019 Apr 5;2[4]:e192416).

The researchers compared the incidence of hospitalization for hip fracture among new denosumab users and new alendronate users during the 3 years after starting treatment. At 3 years, hip fractures occurred in 3.7% of the denosumab group and in 3.1% of the alendronate group. The rate of any fracture was 9% for each group. Although the study design had limitations, the analysis found “no difference between denosumab and alendronate in terms of fracture-risk reduction,” Dr. Bolster said. “Both agents are good agents.”

A recent meta-analysis compared fracture risk with denosumab and any bisphosphonate treatment using data from 10 trials that included more than 5,000 patients (J Clin Endocrinol Metab. 2019 May 1;104[5]:1753-65).

At 12 and 24 months, denosumab produced greater increases in bone mineral density at the spine, hip, and femoral neck. “In fact, there was a greater increase in bone density seen in those on denosumab who had had prior bisphosphonate use,” Dr. Bolster said. In 9 out of 10 trials, however, fracture rate did not differ between patients who received denosumab or any bisphosphonate at 12 or 24 months.


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