Treatment with PTH Peptides

Publisher Summary The emphasis in this chapter is to examine the future potential for harnessing the anabolic effects of parathyroid hormone (PTH), so as to develop effective new treatments for osteoporosis. The prospects are favorable that in the future the majority of patients with spinal osteoporosis and one or more fractures who need an effective form of secondary fracture prevention might be helped by anabolic agents such as parathyroid hormone or one of its fragments. Bisphosphonate treatments agents have more modest effects on bone mass than observed with PTH in the majority of studies, the question arises whether the substantial numbers of patients who are anticipated to be at risk of a “breakthrough” fracture despite bisphosphonate therapy (about 50% of those who would suffer similarly without treatment) would benefit from a second-line treatment such as PTH or an analog. The effectiveness of PTH therapy in restoring mineral mass in bone which has been previously treated with bisphosphonates requires further investigation. Since estrogens and selective estrogen receptor modulators (SERMs, for example, raloxifene), which have similar effectiveness to alendronate against spine fractures, appear to enhance rather than depress the effectiveness of PTH therapy, this might affect the choice of first-line agent in the severely affected patient. Future areas of intensive investigation will include studies on the effectiveness of PTH therapy in bones which will experience relative mechanical disuse, as well as studies of new agents which act through PTH receptor- mediated and novel independent pathways, such as those which promote bone morphogenetic protein 2 production in bone.