In its current study, Dr. Mok’s group contrasted the efficacy of denosumab and oral alendronate in 139 long-term glucocorticoid users. The participants received either subcutaneous denosumab (60 mg every six months) or 70 mg alendronate weekly. The study group contained a high proportion of individuals with SLE (81%), with RA being the next most common subset (9%). The mean dose at treatment entry was 5.1 mg/day prednisolone (or equivalent), although doses as low as 2.5 mg/day were permitted for inclusion.
For patients in both treatment arms, bone mineral density was significantly higher in the spine, hip and femoral neck compared with their pre-study value. But the denosumab group showed a statistically significant greater improvement in bone mineral density after adjusting for the baseline density, age, sex, other osteoporotic risk factors and the cumulative doses of steroids in 12 months.
However, no statistically significant difference was found at the hip and femoral neck after adjusting for those same covariates. Dr. Mok noted the period of treatment of their study was relatively short, and a longer treatment duration might have yielded a clearer difference.
The researchers also analyzed bone markers, such as CTX (i.e., C-terminal telopeptide of type 1 collagen), and adjusted for these same covariates. They found a statistically significant difference between the two groups at 12 months, with the denosumab group more effectively suppressing bone turnover as shown by these indicators.
Dr. Mok pointed out that in contrast to the Amgen study, theirs was not sponsored by any commercial sources.12 He said, “We showed that the magnitude of the increase in spinal [bone mineral density] was comparable with the Amgen study in a subgroup of patients continuing glucocorticoids at 12 months. In general, our results in Asian patients are largely confirmatory.”
It is important to note that neither study provided direct evidence that denosumab is more effective at reducing fracture risk than alendronate. These data may not capture the true extent of the difference between the groups in a real-world setting, in which compliance with bisphosphonates might be decreased. Oral bisphosphonates are known to have poor patient adherence, likely related to their side effect profile. Some studies have indicated higher patient preference and greater adherence with denosumab compared to oral bisphosphonates.10 These new data may help further inform decisions about treatment for prevention of osteoporosis in patients on chronic steroids.
Ruth Jessen Hickman, MD, is a graduate of the Indiana University School of Medicine. She is a freelance medical and science writer living in Bloomington, Ind.
