The effects of abaloparatide on acetabular bone mineral density and proximal femur strength in men with osteoporosis

Abstract

Background: Abaloparatide treatment for 12 months led to significant and rapid increases in bone mineral density (BMD) in the lumbar spine, total hip, and femoral neck compared with placebo in the phase 3 ATOM study (NCT03512262) in men with osteoporosis. Methodology: Acetabular BMD and femur strength were analyzed in separate analyses using dual energy X-ray absorptiometry (DXA) scans from men in the abaloparatide and placebo groups. First, acetabular BMD was calculated in the DeLee and Charnley zones. Second, DXA scans were processed through 3D-Shaper software to generate three-dimensional (3D) patient-specific femur models and calculate femur strength based on a finite element analysis simulating sideways falls. Results and Conclusions: At 6 and 12 months, mean acetabular BMD significantly increased from baseline in all DeLee and Charnley zones with abaloparatide, while little change was noted with placebo. In the second analysis, mean percent change from baseline in femur strength was significantly increased in the abaloparatide treatment group at 6 and 12 months, largely attributable to significant strength increases in the trabecular bone of the femur. Femur and femoral trabecular strength remained near baseline levels in the placebo group. Femoral cortical strength numerically increased in the abaloparatide group at 12 months, though the change was not significant.d The anatomical distribution of changes in major principal stress at failure at 6 and 12 months indicated that the stress at which failure occurs increased at the upper aspect of the femur neck in the abaloparatide group.e In conclusion, abaloparatide improved measured properties in men with osteoporosis on acetabular and femoral sides of the hip joint, increasing acetabular BMD and improving femur strength parameters. Additional research into abaloparatide’s role in managing bone loss at the hip is justified.