RESUMO
Teriparatide is an anabolic therapy for osteoporosis approved in the United States since 2002 and European Union since 2003; however, approval in Japan lagged significantly. This report describes analyses based on International Conference on Harmonisation (ICH) E-5 guidelines that support bridging between Japanese studies and the large Fracture Prevention Trial (FPT). We analyzed data from single teriparatide doses in healthy Japanese and Caucasian postmenopausal women (J-PK) and from studies of 6 months [Phase 2, dose ranging (J-Ph2)] and 12 months [Phase 3, efficacy and safety (J-Ph3)] of randomized, placebo-controlled, once-daily treatment in Japanese subjects with osteoporosis. In J-PK, apparent teriparatide area-under-the-curve (AUC) and peak concentration (C (max)) were up to 40% higher in Japanese versus Caucasian women; however, body weight-adjusted values were comparable between populations; these findings were supported by population pharmacokinetic analyses. Between the FPT and Japanese studies, baseline demographic characteristics were similar but bone mineral density (BMD) at lumbar spine (L1-L4) and body weight were lower for Japanese subjects. With teriparatide 20 µg/day, significant increases in BMD were observed compared to placebo at 12 months in both the FPT and J-Ph3 study, and percent change and actual change in BMD were comparable between studies. Dose response at 6 months was also comparable across populations. No novel safety signals were identified in Japanese subjects. These analyses show that teriparatide clinical data met ICH E-5 criteria for bridging. Findings from foreign trials such as the FPT can thus be extrapolated to Japanese subjects treated with teriparatide 20 µg/day.
