BMD Increased by Romosozumab in Women Transitioning From Bisphosphonates

Romosozumab treatment significantly increased areal bone mineral density (BMD) at the hip and spine compared with teriparatide in women transitioning from bisphosphonate therapy, according to a study published in the Lancet.

Dr Bente Langdahl from the Aarhus University Hospital, Aarhus, Denmark, and colleagues conducted a randomized, phase 3, open-label, active-controlled study (ClinicalTrials.gov identifier: ) of 415 women to compare the effects of romosozumab vs teriparatide on BMD in women with postmenopausal osteoporosis after a 12-month treatment.

Romosozumab 210 mg was given to 206 patients subcutaneously as 3 injections once a month, for a total of 12 doses. Teriparatide 20 μg was delivered by a pen device to 209 patients, who were able to self-administer subcutaneously daily for 12 months.

The mean percentage change from baseline in areal BMD by dual-energy X-ray absorptiometry at the total hip through month 12 was 2.6% (95% Cl, 2.2%-3.0%) in the romosozumab group and −0.6% (95% Cl, −1.0 to −0.2) in the teriparatide group, which resulted in a mean difference between groups of 3.2% (95% Cl, 2.7%-3.8%).

Researchers also evaluated the mean percentage changes from baseline areal BMD by dual-energy X-ray absorptiometry at the total hip, femoral neck, and lumbar spine, which were significantly higher in the romosozumab group (2.9%, 3.2%, and 9.8%, respectively) than in the teriparatide group (−0.5%, −0.2%, and 5.4%, respectively) at month 6 and month 12.

Finally, the romosozumab group saw a greater gain in hip strength from baseline than the teriparatide group at month 6 (2.1% vs −1.0%, respectively) and month 12 (2.5% vs −0.7%, respectively.)

Because patients treated with bisphosphonates often transition to a bone-forming agent, romosozumab could provide a better treatment option for those at high fracture risk, as romosozumab led to greater gains in hip BMD than teriparatide.

“These results suggest that romosozumab might offer a unique benefit to patients with postmenopausal osteoporosis,” concluded Dr Langdahl and colleagues.

Study Limitations

• The study was open-label, as the teriparatide pen could not be masked.
• The study could not assess the difference in fracture incidence between treatment groups, and fracture events were not adjudicated or confirmed.
• The study could not measure any changes in the degree of mineralization.
• The duration of the study was 12 months, yet teriparatide is approved for up to 24 months. Therefore, it is unknown whether teriparatide would have resulted greater BMD gains if participants were exposed to it for a longer duration.

follow @RheumAdvisor

References

1. Langdahl BL, Libanti C, Crittenden DB, et al. Romosozumab (sclerostin monoclonal antibody) versus teriparatide in postmenopausal women with osteoporosis transitioning from oral bisphosphonate therapy: a randomised, open-label, phase 3 trial [published online July 26, 2017]. Lancet. doi: 10.1016/S0140-6736(17)31613-6