Key BMD and biomarker findings
BMD increased significantly in the spine, hip, and femoral neck in both treatment groups by 12 months. However, after adjustment for baseline BMD and covariates including age, menopause, and history of fracture, the gains in the denosumab group were significantly higher.
The increase in lumbar spine BMD at 12 months of 3.5% in the denosumab group versus 2.5% in the alendronate group was statistically significant (P = .045). Less significant was a 0.9% increase at the hip in the denosumab patients versus 1.6% in the alendronate group (P = .10), as well as femoral neck BMD gains of 1% in the denosumab group versus 1.5% in the alendronate group (P = .86).
Furthermore, “denosumab was more potent in suppressing the bone markers at 12 months,” Dr. Mok said.
Specifically, the percentage decrease in serum PINP (procollagen type I N-terminal propeptide) levels in the denosumab group was significantly greater than in the alendronate group (P = .001). Likewise, the decrease in CTX (C-terminal telopeptide of type I collagen) was significantly greater in the denosumab cohort versus the alendronate cohort (P < .001).
“Dr. Mok’s study was a well-controlled investigation. The superiority of denosumab was impressive, especially given the small group sizes of 69 and 70,” session comoderator Gregg Silverman, MD, professor in the department of internal medicine and the department of pathology at New York University, said when asked for comment.
“However, bone density measurements may not tell the whole story. These results support a bigger and much larger-scale study to confirm that rates of fracture on denosumab are also reduced.”
No new symptomatic fractures occurred in either group during the study. The investigators are evaluating for any new radiologic fractures, with results pending.
Dr. Mok said “results of our study in Asian patients are largely confirmatory” of a previous 2018 comparison study and a 2019 comparison study, each sponsored by Amgen.
A small sample size, short duration of treatment, and the open-label design were limitations of the study.
The trial was an investigator-initiated study. Dr. Mok and colleagues had no relevant financial disclosures. Dr. Silverman had no relevant financial disclosures.
SOURCE: Mok CC et al. Arthritis Rheumatol. 2020;72(suppl 10). ACR 2020, Abstract 1442.