Romosozumab Increases Bone Density in Postmenopausal Women
New findings presented at EULAR congress
A new study presented June 11 at the European League Against Rheumatism Annual Congress (EULAR 2014) has shown that, in postmenopausal women with low bone mass, the monoclonal antibody romosozumab (Celltech/Amgen) significantly increased both bone mineral density (BMD) and bone mineral content in the spine and hip compared with the commonly prescribed anabolic agent teriparatide (Forteo, Eli Lilly).
“The use of teriparatide, an effective anabolic agent which can stimulate bone growth and reduce the risk of fractures, is potentially problematic due to the requirement for daily subcutaneous injection, its relatively high cost, and also a black box warning about the risk of inducing osteosarcoma in rats,” said lead investigator Professor Harry K. Genant of the University of California, San Francisco.
An international, randomized, placebo-controlled, phase II study enrolled postmenopausal women aged 55 to 85 years. Quantitative computed tomography measurements were performed at the total lumbar spine (i.e., the mean of L1 and L2 entire vertebral bodies) and at the total hip in subjects receiving subcutaneous romosozumab (210 mg monthly), subcutaneous teriparatide (20 mcg once daily), or placebo. The percentage changes from baseline in cortical and trabecular BMD and in bone mineral content were evaluated at 12 months.
Treatment with romosozumab, administered subcutaneously at monthly intervals over the 12-month study period, resulted in gains in both the trabecular and cortical compartments of the spine and hip regions. Important differences were observed between romosozumab and teriparatide depending on the skeletal location.
In the lumbar spine, treatment with romosozumab and teriparatide achieved similar and significant gains versus baseline in trabecular BMD (+18.3% vs. +20.1%, respectively; P < 0.05). However, in the hip, gains in trabecular BMD were significantly greater with romosozumab than with teriparatide (+10.8% vs. +4.2%, respectively; P = 0.01). Gains in cortical BMD were also greater with romosozumab compared with teriparatide at the lumbar spine (+13.7% vs. +5.7%; P < 0.0001) and hip (+1.1% vs. +0.9%, P = 0.12).
Moreover, gains in cortical bone mineral content were significantly greater with romosozumab compared with teriparatide at both the lumbar spine (+23.3% vs. +10.9%; P < 0.0001) and the hip (+3.4% vs. 0.0%; P = 0.03).
Romosozumab is a monoclonal antibody that binds to sclerostin — an osteocyte-derived inhibitor of osteoblast activity. As a result, romosozumab stimulates bone formation and decreases bone resorption.
Approximately 30% of all postmenopausal women have osteoporosis in the U.S. and Europe; at least 40% of these women will go on to sustain one or more fragility fractures in their lifetime.
The most common fractures associated with post-menopausal osteoporosis occur at the hip, spine, and wrist. Of particular concern are vertebral and hip fractures. Vertebral fractures can result in intense back pain and deformity. A hip fracture usually requires surgery and may result in loss of independence or even death in an elderly frail patient.
Source: EurekAlert; June 11, 2014.