Biologicals in osteoporosis: teriparatide and parathyroid hormone in women and men.

Osteoporosis is characterized by the occurrence of a host of fractures. According to densitometric values, an operational definition for osteoporosis corresponds to a loss of 25% to 30% (-2.5 T-scores) compared with the mean values of bone mineral density of young premenopausal women. For years, research tried to develop drugs to improve the bone mineral density. According to the compounds, antiresorptive agents are able to decrease the fracture rate by about 30% to 70%, and to increase the bone mineral density. However, the agents increasing the most bone mineral density are not necessarily those that influence the most fracture rates. It has been known for years that parathyroid hormone (PTH) administered cyclically is able to increase bone mineral density. Two analogues of PTH have been developed: PTH (1-34) and PTH (1-84). Both of them are able to increase bone mineral density and reduce the rate of vertebral fracture but not of the hip, nor of nonvertebral fractures, the latter at least for PTH (1-84). Their exact place in the armamentarium of therapy of osteoporosis and their best time of administration are not yet definitely settled. New modes of administration (transdermal, intranasal, oral) will probably become available soon. With all the drugs available today and those still in development, it can be hoped that osteoporosis will become a disease of the past.