For osteoporosis a new molecular drug that activates bone formation without bone resorption has been reported in the New England Journal of Medicine. Treatment with romosozumab in post menopausal women with low bone mineral density was compared with two standard osteoporosis drugs.
Romosozumab binds to sclerostin — an inhibitor of osteoblast activity. Michael McClung MD, Director, Oregon Osteoporosis Center, Portland, Oregan and his colleagues looked at 400 women allocated to different doses and schedules of the new drug:
“Over the 12 months time significant increases in bone density with all the doses of romosozumab were observed in the spine and in the hip region. And with the largest dose of romosozumab the increase in the spine of 11.3 per cent over the 12 month time period was much larger than seen with the comparators —alendronate or teriperatide — and was the greatest increase that we’ve observed in bone density in a 12 month interval with any treatment that we’ve ever evaluated”, Dr McClung told AudioMedca.com in an interview.
He explained that alendronate stimulates bone formation and resorption while the bisphosphonates decrease the activity of bone metabolism — and prevent the progression of bone loss — but can’t stimulate growth of new bone. Romosozumab, on the other hand, modulates all the bone growth parameters in the desired direction.
Since sclerostin is only found in bone cells any drug targeting it should — theoretically — be intrinsically specific and hopefully have few toxicities. Dr McClung said they were expecting rososozumab to be safe and indeed in the study they found few adverse events of any kind.
He suggested how this agent could potentially being used: “Further trials documenting its effect on protecting patients from fractures — which is the major objective of treatment — are already under way. So assuming that all goes well: for patients with severe osteoporosis — who truly are in need of skeletal reconstruction — then the use of a drug like romosozumab for an interval of perhaps a year — to markedly activate bone formation and to rebuild the skeleton — would be useful,” he explained. “For patients with milder forms of osteoporosis the drugs we currently have like denosumab and the bisphosphonates would — likely — still be the preferred treatment.”
SOURCE: “Romosozumab in Postmenopausal Women with Low Bone Mineral Density”
January 1, 2014 DOI: 10.1056/NEJMoa1305224
Michael McClung MD
Director, Oregon Osteoporosis Center, Portland, Oregon