IBMS BoneKEy | BoneKEy Watch
Romosozumab, a sclerostin-blocking antibody, increases BMD in postmenopausal women
DOI:10.1038/bonekey.2014.32
In this Phase 2 international multicenter trial, romosozumab, an antibody that binds sclerostin and enhances bone formation, was given to postmenopausal women with low bone mineral density (BMD). Groups were: monthly romosozumab at three different doses (70 mg, 140 mg or 210 mg), quarterly at two different doses (140 mg or 210 mg); comparators: alendronate (70 mg weekly) or teriparatide (20 μg daily); placebo.
Women who received romosozumab showed significantly increased bone density at the lumbar spine compared with a decrease of 0.1% in the placebo group. The highest increase in the romosozumab-treated groups was 11.3%, measured in women given the 210-mg monthly dose. Alendronate produced an increase of 4.1% and teriparatide an increase of 7.1%. Significant increases in BMD were also observed at the total hip and at the femoral neck.
Positive signs were also detected in secondary endpoints: the bone-resorption marker serum β-CTX showed a sustained fall, and there were also transitory increases in markers of bone formation. Adverse events were similar in all groups with just a few injection site reactions in the antibody-treated groups.
Editor’s comment: First year results of this Phase 2 trial are very promising, with gains in BMD that are twice as large as the comparators. Yet the bone turnover markers suggest a rapid exhaustion of the bone forming properties, but a persistent decrease in bone resorption, the mechanisms of which remain to be elucidated. Whether romosozumab bone anabolic effects will resume upon re-exposure also remains to be demonstrated.
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