Combination therapy with denosumab and teriparatide effected greater increases in cortical and trabecular bone density compared with treatment with either drug alone in postmenopausal women with osteoporosis, according to study results presented at the American Society for Bone and Mineral Research (ASBMR) 2014 Annual Meeting.
In the study, 94 postmenopausal women aged 51 to 91 years with osteoporosis were randomly assigned once daily subcutaneous teriparatide 20 mcg, subcutaneous denosumab 60 mg every 6 months or combination therapy with denosumab and teriparatide for 24 months.
Increases in total and trabecular volumetric bone mineral density (vBMD) at both the radius and tibia were noted in the denosumab monotherapy and combination therapy groups but not in the teriparatide monotherapy group, according to the researchers.
In the combination therapy group, the increase in total vBMD at both the radius and tibia exceeded those observed in either the denosumab monotherapy and teriparatide monotherapy groups (P<.005 for all between-group comparisons).
The increase in trabecular vBMD was greater in the combination therapy group vs. either monotherapy group at the radius only (P<.002 for both), according to the data.
Cortical vBMD also remained stable or received a boost with combination therapy and denosumab monotherapy at the radius and tibia, with researchers noting a greater increase in tibial cortical BMD in the combination group vs. either monotherapy group (P<.002 for both). In the teriparatide monotherapy group, however, cortical vBMD declined.
Similarly, the researchers found increases in cortical thickness at the radius and tibia in both the combination therapy and denosumab monotherapy groups, but noted no change in the teriparatide monotherapy group. The combination therapy group also exhibited a greater increase in cortical thickness at the tibia compared with both monotherapy groups (P<.001 for both).
During the second year of therapy, total vBMD and cortical thickness continued to increase in the combination therapy group, the researchers noted, whereas cortical vBMD decreased during 2 years in the teriparatide alone group.
Women who had used IV or oral bisphosphonates in the past 6 months were excluded from the study.
The researchers concluded that this study linked combination therapy with teriparatide and denosumab with increases in total vBMD at the radius and tibia, increases in trabecular vBMD at the radius and increases in cortical thickness at the tibia more than treatment with either therapy alone.
“Furthermore, the [teriparatide]-induced decrease in [cortical vBMD] is fully prevented by [denosumab] co-administration,” the researchers wrote in an abstract. “The combination of [denosumab] and [teriparatide] results in the most favorable changes in peripheral bone density and geometry and may prove a useful intervention in women at high risk of fracture.”
- Tsai J et al. Abstract 1046. Presented at: American Society for Bone and Mineral Research 2014 Annual Meeting; Sept. 12-15, 2014; Houston, Texas.