Romosozumab is associated with greater trabecular bone score improvement compared to denosumab in postmenopausal osteoporosis

Mini abstract: In this study, romosozumab demonstrated significantly greater improvement in trabecular bone score compared to denosumab therapy in postmenopausal women previously treated with antiresorptive agents. Notably, in patients previously treated with anti-resorptive agents, treatment with romosozumab resulted in similar increases in trabecular bone score compared to that of drug-naïve patients. Purpose: Romosozumab significantly increases bone mineral density (BMD) and rapidly reduces fracture risk. Whether romosozumab can improve the spinal trabecular bone score (TBS) as a bone quality indicator merits further investigation. Methods: Data for postmenopausal women starting romosozumab or denosumab treatment at Severance Hospital, Korea, were analyzed. Romosozumab and denosumab groups were 1:1 matched using propensity scores, considering relevant covariates. Good responders were defined as those with TBS improvement of 5.8% or greater. Results: Overall, 174 patients (romosozumab, n = 87; denosumab, n = 87) were analyzed. Matched groups did not differ in age (64 years), weight, height, previous fracture (38%), lumbar spine or femoral neck BMD (T-score, -3.4 and -2.6, respectively), or prior bisphosphonate or selective estrogen receptor modulator (SERM) exposure (50%). The romosozumab group exhibited a greater increase in lumbar spine BMD (15.2% vs. 6.9%, p < 0.001) and TBS (3.7% vs. 1.7%, p = 0.013) than the denosumab group. In patients transitioning from bisphosphonate or SERM, romosozumab users showed greater improvement in TBS compared to denosumab users (3.9% versus 0.8%, P = 0.006); the drug-naive group showed no significant difference (3.6% versus 2.7%, P = 0.472). The romosozumab group had a higher proportion of good responders than the denosumab group (33.3% vs. 18.4%, p = 0.024). Romosozumab therapy for 12 months resulted in 3.8-fold higher odds of a good response in TBS than denosumab after covariate adjustment (adjusted odds ratio 3.85, p = 0.002). Conclusion: Romosozumab could improve bone mass and bone quality, measured by TBS, in postmenopausal osteoporosis, particularly as a subsequent regimen in patients previously taking anti-resorptive agents.