Romosozumab increases BMD gains and improves T-scores
Cosman F, Lewiecki EM, Ebeling PR, et al. T-score as an indicator of fracture risk during treatment with romosozumab or alendronate in the ARCH trial. J Bone Miner Res. 2020;35:1333-1342
Romosozumab (Evenity) is a monoclonal antibody that binds and inhibits sclerostin, thus having the dual effect of increasing bone formation and decreasing bone resorption.16 It is administered for 1 year as monthly doses of 210 mg subcutaneously. Previous studies have shown that romosozumab produces large increases in lumbar spine and total hip BMD,17 reduces the risk of new vertebral and clinical fractures compared with placebo,16 and reduces the risk of vertebral, clinical, nonvertebral, and hip fractures compared with alendronate over a median treatment period of 33 months (the ARCH study).18
According to the package insert, romosozumab is indicated “for the treatment of osteoporosis in postmenopausal women at high risk for fracture, defined as a history of osteoporotic fracture, or multiple risk factors for fracture; or patients who have failed or are intolerant to other available osteoporosis therapy.”
Should T-score be a therapeutic target?
Cosman and colleagues performed a post hoc analysis of the ARCH trial specifically to evaluate mean BMD and corresponding mean T-score changes (and the relationships between T-scores) after 1 year of romosozumab or alendronate therapy and subsequent fracture incidence. The study is quite detailed with much numerical data and statistical analysis.
Basically, the ARCH trial randomly assigned patients with osteoporosis to receive either monthly subcutaneous romosozumab 210 mg or weekly oral alendronate 70 mg for 12 months. After the double-blind portion of the trial, all patients received open label weekly oral alendronate 70 mg through the end of study (24 months), although they were still blinded to the initial treatment assignment. In addition, patients received daily calcium and vitamin D supplements.
The data analysis found that 1 year of romosozumab led to larger BMD gains than alendronate therapy. Also, the T-score achieved with either therapy was directly related to subsequent fracture risk. The authors thus proposed that these data support the use of the T-score as a therapeutic target for patients with osteoporosis.
It is important to note that in the original ARCH study, the participants’ average age was 71 years and approximately one-third were older than 75. The average T-score was -2.7 at both the lumbar spine and femoral neck. Approximately 20% of patients had a pre-existing vertebral fracture, and approximately 20% had a previous nonvertebral fracture.
The authors of the current study, furthermore, found that mean BMD gains after 1 year of romosozumab treatment were more than twice those seen with alendronate at the total hip, femoral neck, and lumbar spine. These BMD changes resulted in a larger proportion of patients who achieved T-scores above the osteoporosis level at each of the skeletal sites after 1 year of therapy. Fewer fractures occurred during the second year and the entire open label period among patients who had received romosozumab first compared with those who received alendronate.●
WHAT THIS EVIDENCE MEANS FOR PRACTICE
Women’s HCPs need to be aware of romosozumab even if they are not the ones primarily to prescribe it. Perhaps familiarity with the drug will allow some clinicians to begin to implement this treatment into their care for elderly patients with osteoporosis, especially those with pre-existing fractures. It may be useful to monitor patients’ total hip T-score while on treatment if osteoporosis treatment goals have been achieved to minimize future fracture risk.
Women’s HCPs need to be aware of romosozumab even if they are not the ones primarily to prescribe it. Perhaps familiarity with the drug will allow some clinicians to begin to implement this treatment into their care for elderly patients with osteoporosis, especially those with pre-existing fractures. It may be useful to monitor patients’ total hip T-score while on treatment if osteoporosis treatment goals have been achieved to minimize future fracture risk.