Once-Weekly Injection of Low-Dose Teriparatide (28.2 μg) Reduced the Risk of Vertebral Fracture in Patients with Primary Osteoporosis

We conducted a randomized, double-blind trial to assess the effect of 28.2 mu g teriparatide versus placebo (1.4 mu g teriparatide) on reduction of the incidence of vertebral fractures. Individuals enrolled in this study included patients with primary osteoporosis with one to five vertebral fractures and capable of self-supported walking. Attention was focused on incident vertebral fractures, change in bone mineral density (BMD) of the lumbar spine, and safety. A total of 316 subjects participated in the study, which lasted up to 131 weeks. Incident vertebral fractures occurred in 3.3 % of subjects in the 28.2 mu g teriparatide-treated group and 12.6 % of subjects in the placebo group during the 78-weeks study period. Kaplan-Meier estimates of risk after 78 weeks were 7.5 and 22.2 % in the teriparatide and placebo groups, respectively, with a relative risk reduction of 66.4 % by teriparatide (P = 0.008). Lumbar BMD in the 28.2 mu g teriparatide group increased significantly by 4.4 +/- A 4.7 % at 78 weeks, which was significantly higher than the corresponding data in the placebo group (P = 0.001). Adverse events were observed in 86.7 % of individuals in the teriparatide group and 86.1 % of those in the placebo group. In conclusion, weekly injection of a low-dose of teriparatide (28.2 mu g) reduced the risk of incident vertebral fractures and increased lumbar BMD.