The effects of switching daily teriparatide to oral bisphosphonates or denosumab in patients with primary osteoporosis

The aim of this 12-month, observational study was to compare the effects of switching daily teriparatide (TPTD) to oral bisphosphonates (BP) therapy or denosumab (DMAb) therapy in patients with primary osteoporosis. Patients [n = 78; 71 postmenopausal women and seven men; mean age 76.3 (64-94) years; mean duration of prior daily TPTD therapy 20.1 (6-24) months] were allocated to either the (1) switch-to-BP group [n = 36; weekly alendronate 35 mg (n = 19), weekly risedronate 17.5 mg (n = 12), monthly minodronate 50 mg (n = 5)]; or (2) switch-to-DMAb group (n = 42; 60 mg sc every 6 months) based on each physicians' decision. Changes in bone mineral density (BMD) and serum bone turnover markers were monitored every 6 months. No significant difference was observed in baseline clinical characteristics between the groups. After 12 months, the increase in BMD was significantly greater in the switch-to-DMAb group compared to the switch-to-BP group: lumbar spine (6.2 vs. 2.6 %; P < 0.01), total hip (4.2 vs. 1.1 %; P < 0.05), and femoral neck (3.5 vs. 1.4 %; P < 0.05). In addition, the patients in the switch-to-DMAb group showed a significant decrease compared to those in the switch-to-BP group in TRACP-5b (-55.8 vs. -32.8 %; P < 0.01) and ucOC (-85.5 vs. -65.0 %; P < 0.001), while no significant difference was observed in PINP (-67.5 vs. -62.1 %). Switching daily TPTD to DMAb significantly increased BMD and decreased bone resorption marker compared to switching to oral BP at 12 months, and thus may provide an effective sequential treatment option after daily TPTD treatment.