A new age of osteoanabolic therapy? A real-world, two-centre study comparing effects of romosozumab, teriparatide, and antiresorptive therapies for osteoporosis.

UNLABELLED: Romosozumab demonstrates strong real-world effectiveness in improving bone density, with particularly pronounced gains at the lumbar spine. Treatment-naïve patients derive the greatest benefit. Lumbar spine improvements surpass those achieved with teriparatide or anti-resorptive therapies, and longer prior exposure to anti-resorptives is associated with attenuated responses to romosozumab.

INTRODUCTION

Osteoporosis is a progressive disease that leads to considerable morbidity. The osteoanabolic agent romosozumab has shown efficacy in clinical trials, enhancing bone mineral density (BMD) and reducing fracture risk. However, real-world evidence, particularly in patients receiving long-term anti-resorptive therapy, remains limited. This study aimed to characterise real-world outcomes of romosozumab use in an Australian cohort, identifying predictors of optimal response following standard anti-resorptive treatment.

METHODS

This retrospective cohort study identified 53 patients treated with romosozumab from the electronic medical record (eMR) at tertiary hospitals between 2021 and 23 who had completed 12 months of therapy and where baseline and follow-up DXA scans were available for analysis. Comparative data for teriparatide and anti-resorptive treatment cohorts were obtained from prior eMR datasets (n = 54 and n = 60, respectively).

RESULTS

Romosozumab treatment led to BMD increases at the lumbar spine (LS), total hip (TH), and femoral neck (FN), with a decrease at the wrist (p < 0.05). Mean BMD gains at LS were significantly higher with romosozumab than with teriparatide (11.3 ± 8.2% vs. 5.0 ± 8.6%, p < 0.001) and anti-resorptive treatment (11.3 ± 8.2% vs. 6.6 ± 6.1%, p < 0.001). Treatment-naïve patients achieved more pronounced gains at LS (14.0 ± 6.6%); TH (5.0 ± 1.7%) compared to those with prior anti-resorptive therapy (LS 10.7 ± 8.5%, p = 0.220; TH 1.9 ± 5.8%, p = 0.009). Duration of previous anti-resorptive treatment was inversely correlated with LS BMD gains on romosozumab (r = - 0.305, p = 0.026). Linear regression showed that more vertebral fractures, longer prior anti-resorptive use, and higher baseline LS BMD each attenuated the LS BMD response to romosozumab, with romosozumab outperforming teriparatide and anti-resorptives, while teriparatide showed no significant difference from standard anti-resorptives.

CONCLUSION

Romosozumab provides real-world efficacy in BMD improvement, particularly at the LS, with significantly greater gains than those seen with teriparatide or standard therapies. Prior anti-resorptive use may attenuate romosozumab's anabolic effects, suggesting that treatment-naïve patients may benefit most from this therapy.