Potent treatments for bone loss highlighted

For those with severe bone loss and osteoporosis, there are a number of powerful and effective treatments available, the Irish Osteoporosis Society 2025 Annual Medical Conference for Health Professionals heard.

Dr Donal Fitzpatrick, Consultant Geriatrician, St James’s Hospital, Dublin, discussed the role of denosumab, a human monoclonal antibody for the treatment of bone loss in severe osteoporosis, administered every six months.

Dr Fitzpatrick noted its efficacy and safety for long-term use, but warned against delayed injections or abrupt discontinuation due to rapid bone loss and fracture risk.

There is evidence that denosumab discontinuation causes rapid bone loss within one year, which increases the risk of multiple vertebral fractures, particularly among those with existing vertebral fractures. The decision to use denosumab, therefore, needs to be carefully considered.

If stopped at a future point, bisphosphonates – even with up to three doses of zoledronic acid – may not prevent subsequent bone loss.

“There must be a compelling reason to stop and the patient must be low risk. Treatment beyond 10 years is not a reason to stop,” Dr Fitzpatrick said. Denosumab is also thus not a suitable agent for ‘drug holidays’, he added. 

In the next presentation, Dr Kevin McCarroll, Consultant Physician and Geriatrician, Bone Health Unit, St James’s Hospital, discussed romosozumab, a monoclonal antibody that targets sclerostin, a protein that inhibits bone formation and also promotes bone resorption.

Romosozumab is unique in having both anabolic and antiresorptive effects, making it the most potent osteoporosis therapy for increasing bone mineral density and reducing fracture risk developed to date, he explained.

Romosozumab is not only superior at increasing bone mineral density compared to bisphosphonates and denosumab, but also teriparatide, the only other bone-forming therapy available in Ireland, Dr McCarroll stated. It is well tolerated, with only about 5 per cent discontinuing the drug due to adverse effects. However, its use warrants caution in individuals with high cardiovascular risk.

In the FRAME trial, one year of romosozumab therapy resulted in a 13.3 per cent gain in bone mineral density at the lumbar spine and 6.8 per cent at the total hip, with a 73 per cent reduction in new vertebral fractures and a 36 per cent reduction in clinical fractures, Dr McCarroll noted.

While approved by the US FDA and European Medicines Agency in 2019, romosozumab was finally made available in Ireland in November 2024.

It is limited here to postmenopausal women with severe osteoporosis who meet certain strict criteria. Dr McCarroll said it is hoped it will become more accessible in time.