Objective(s): The FNIH-ASBMR SABRE project1 defined the bone mineral density (BMD) surrogate threshold effect (STE) required to predict a significant reduction in fracture (fx) at the study level. STEs in the FNIH-ASBMR SABRE project were calculated using difference in BMD percentage change at 24 months (M) between active and placebo (PBO).1 In practice, a more clinically relevant measure is whether patients’ (pts’) BMD has improved with treatment from their own baseline (BL) values. This post hoc analysis of data from FRAME (NCT01575834) and ARCH (NCT01631214) assessed the percentage of pts achieving the established FNIH STE thresholds1 with romosozumab (Romo) or alendronate (ALN) at 12M and 24M when compared to their own BMD values at BL.2,3
Materials and Methods: Postmenopausal women with osteoporosis were randomised to Romo 210mg monthly (QM) or comparator (FRAME: PBO QM; ARCH: alendronate [ALN] 70mg QW) for 12M). After 12M all pts received ALN in ARCH or denosumab (DMAB) in FRAME. Here, we report the proportion of pts that achieved total hip BMD percentage changes at 12M and 24M that meet STEs for vertebral, nonvertebral, hip and any fx risk reduction (observed case), without comparison to PBO.
Results: The table displays the percentage of patients achieving BMD changes from BL corresponding to the STEs for each fracture category.
Conclusion(s): Within 12M of treatment with Romo, most patients achieved the FNIH-SABRE STEs for any reduction in fx risk. At both 12 and 24M, higher proportions of patients met the STEs with Romo compared to ALN for all fx types.
References: 1. Eastell, R. JBMR 2021; Epub; 2. Cosman F. NEJM 2016;375:1532–431; 3. Saag K. NEJM 2017;377:1417–27.