Purpose: Investigate relationships between subject characteristics and BMD responses after transitioning from DMAb to ALN.
Methods: DAPS (NCT00518531) was a 24-month, open-label, randomised, cross-over study that compared adherence to 12 months (M) of DMAb (60 mg Q6M SC) with ALN (70 mg QW PO) in treatment-naïve postmenopausal women; T-score ≤─2.0 to ≥─4.0 at the lumbar spine (LS), total hip (TH), or femoral neck (FN). BMD was measured at baseline, M12 and M24. Here we evaluate subjects transitioning from DMAb to ALN at M12. A 3% BMD least significant change threshold identified subjects who lost, maintained, or gained BMD from M12 to M24. Characteristics were summarised using descriptive statistics.
Results: Of 126 subjects randomised to DMAb, 115 (91%) transitioned to ALN at M12. At baseline, the mean age was 65 years and mean BMD T-scores were ─2.0, ─1.6, and –2.0 at the LS, TH, and FN, respectively. BMD increased by 5.6%, 3.2%, and 3.1% with DMAb from M0 to M12 at the LS, TH, and FN, respectively, and changed by 0.6%, 0.4%, and –0.1% with ALN from M12 to M24. After transitioning to ALN, most subjects showed maintained or increased BMD (Table); 15.9%, 7.6%, and 21.7% lost BMD at the LS, TH, and FN, respectively, and only 1 subject (1.2%) lost BMD at all 3 sites. Baseline characteristics, M12 BMD, and adherence to ALN showed no trend with BMD change from M12 to M24. However, subjects who lost BMD from M12 to M24 on ALN showed greater BMD gains from M0 to M12 on DMAb, and few who lost BMD fell below their pre-study baseline BMD. No subject experienced clinical vertebral fracture.
Conclusion: These data highlight the need for oral BP therapy following DMAb cessation and BMD monitoring of patients transitioning from DMAb to ALN.
Acknowledgments: Amgen Inc. sponsored this study.