Bone Abstracts (2013) 1 PP436 | DOI: 10.1530/boneabs.1.PP436

Bone mineral density changes in patients with prior fracture suboptimally treated with a bisphosphonate: results from denosumab (DMAb)/ibandronate and DMAb/risedronate trials

Christopher Recknor1, Christian Roux2, Pei-Ran Ho3, Jesse Hall3, Henry Bone4, Sydney Bonnick5, Joop van den Bergh6, Irene Ferreira7, Rachel Wagman3 & Jacques P Brown8


1United Osteoporosis Centers, Gainesville, GA, USA; 2Paris Descartes University, Paris, France; 3Amgen Inc., Thousand Oaks, CA, USA; 4Michigan Bone and Mineral Clinic, Detroit, MI, USA; 5Clinical Research Center of North Texas, Denton, TX, USA; 6VieCuri Medical Centre, Maastricht University, Maastricht, The Netherlands; 7Amgen Ltd., Cambridge, UK; 8CHUQ-CHUL Research Centre, Quebec City, QC, Canada.


: In osteoporosis, poor adherence to bisphosphonate (BP) therapy is common, and is associated with poor outcomes and increased treatment costs (Siris 2006; Recker 2005). Although compliance is improved with monthly vs weekly dosing (Reginster 2008), no evidence suggests cycling through BP agents offers therapeutic benefit, assessed by bone mineral density (BMD). In two randomized, open-label studies in postmenopausal women aged ≥55 years previously treated with, but suboptimally adherent to, BP therapy, subjects received denosumab (DMAb) 60 mg SC Q6M, ibandronate (IBN) 150 mg PO QM or risedronate (RIS) 150 mg PO QM for 12 months; DMAb treatment was associated with greater increases in BMD than either IBN or RIS (Recknor 2012; Roux 2012). We assessed if these differences were consistent in a subset of subjects who had BMD data recorded at baseline and month 12 stratified by prior fragility fracture. In the IBN and RIS studies, 237/767 (31%) and 280/809 (35%) subjects, respectively, had a prior fracture. There were no significant differences in baseline BMD by treatment group or prior fracture. BMD increases were greater with DMAb than IBN or RIS at all sites independent of prior fracture (Table). In subjects suboptimally adherent to an oral BP, switching to DMAb provided greater gains in BMD at all key skeletal sites measured than transitioning to either IBN or RIS. These findings suggest that the magnitude of treatment effect is not significantly influenced by classification of high risk, as defined by prior fragility fracture.

DMAb vs IBN studyDMAb vs RIS study
Prior fractureDMAb (n=399)IBN (n=368)PintDMAb (n=405)RIS (n=404)Pint
THNo2.2%1.3%*0.51.9%0.3%*0.647
Yes2.4%0.6%*2.2%0.5%*
FNNo1.5%1%†0.0021.5%−0.3%*0.157
Yes2.2%0.1%*1.4%0.3%‡
LSNo4.1%2.2%*0.2843.4%0.8%*0.231
Yes4.2%1.6%*3.4%1.4%*
* P<0.001; † P=0.0382; ‡ P=0.0014. Pint =P-value for treatment-by-subgroup interaction