Review on December 03, 2009
Teriparatide (recombinant human parathyroid hormone) is a hormone therapy that is used to treat osteoporosis in men and also women who have been through menopause. The Fracture Prevention Trial (FPT) was a randomized, placebo-controlled investigation involving 1637 women with post-menopause osteoporosis. It found that using 20 or 40 µg of teriparatide hormone therapy each day greatly reduced the risk of vertebral fracture during an average of18 months of this hormone therapy. This particular study looks at the safety and occurrence of new vertebral fractures after finishing teriparatide hormone therapy.
Postmenopause women in the FPT were asked to return for follow-up visits to provide statistics on fracture reduction after discontinuing teriparatide hormone therapy. Not many studies have examined the degree to which the antifracture effectiveness of osteoporosis drugs is maintained in post-menopause women after hormone therapy has been stopped. This study pays particular attention to whether or not the reduction in vertebral fracture risk observed in post-menopause women during the FPT continued up until to the 18-month follow-up visit.
Data showed that during the follow-up, protection against new vertebral fractures was linked to previous teriparatide hormone therapy use and to the fewer vertebral fractures that occurred during the FPT in post-menopause women treated with this kind of hormone therapy.
It was established that teriparatide hormone therapy use by post-menopause women also defended against later fracture during follow-up, indicating that it could halt the cycle of accelerating risk fracture, which is typical of advanced osteoporosis, and evident in a follow-up study in post-menopause women who had previously taken placebo.
Change in vertebral T-score during hormone therapy is a highly associated outcome of post-menopause women's treatment with teripararide hormone therapy. This could have also possibly explained a large section of the constant reduction in fracture risk in post-menopause females throughout the follow-up study.
Dempster and colleagues described improvements in bone microarchitecture in paired biopsy samples from post-menopause women with osteoporosis treated with human parathyroid hormone therapy for 36 months. Parathyroid hormone therapy increased trabecular connectivity and cortical thickness and eliminated deficiencies in microarchitecture associated with increased skeletal weakness. These improvements might impact on fracture risk in post-menopause women after parathyroid hormone therapy has ended.
This investigation shows that vertebral fracture risk reduction in post-menopause women by teriparatide hormone therapy administration continues for a minimum of 18 months after this type of hormone therapy has ended. During the follow-up study there were no indications of hidden adverse effects of previous teriparatide hormone therapy or undesirable effects associated with ending the therapy. It is almost certain that this is the first large osteoporosis examination offering data on vertebral fracture occurrence after withdrawal of osteoporosis drug treatment. Yet, as with most studies of this nature, there are limitations and so more randomized controlled trials are needed to confirm the extent to which sequential hormone therapy with other agents might further reduce vertebral fracture risk in postmenopausal women.