Objective: To bridge the efficacy and compare the safety of the 24-week teriparatide treatment in a Chinese osteoporosis study (NCT00414973) to a large international trial (FPT, NCT00670501) to determine whether long-term results from the international study were applicable to Chinese patients.
Methods: In this post-hoc analysis, a propensity score matching method was used to select patients with similar baseline characteristics. Patients were female with osteoporosis at high risk of fracture, aged ≥55 years, and had no history of rheumatoid arthritis or corticosteroid use. Outcomes included percentage changes in lumbar-spine bone mineral density (LS-BMD) from baseline to 24 weeks, safety in matched-pair patients, and long-term percentage changes in LS-BMD and fragility fracture incidence in the matched fracture prevention trial (FPT) population. The determination of the acceptability of bridging results was based on the International Conference on Harmonization E5 guidelines.
Results: A total number of 228 patients from each study were matched and paired. Patients were similar at baseline (P -values >0.33) except for ethnicity (98% Caucasian for FPT). For changes in LS-BMD from baseline to week 24, treatment with teriparatide showed significantly greater increases (P -values <0.001; least-squares mean difference: 5.0% in the Chinese study and 5.4% in FPT) than comparator (calcitonin/placebo). The safety profiles over 24 weeks were similar between two studies. For matched-pair FPT patients, long-term changes in LS-BMD were significantly greater (least-squares mean difference: 11.5%, P <0.001) and the fragility fracture rate was marginally lower in the teriparatide group compared with the placebo group (13.1% vs 22.3%, P =0.070).
Conclusion: Assuming similar pharmacokinetic profiles for teriparatide between populations, comparable increases in LS-BMD and consistent safety profiles within 24 weeks of the treatment suggest long-term LS-BMD results from the FPT may be applicable to Chinese population.
Keywords: osteoporosis, teriparatide, bridging, lumbar spine-bone mineral density, LS-BMD, fracture prevention trial