New anabolic therapies for osteoporosis.

Osteoporosis is characterized by low bone mass and qualitative structural abnormalities of bone tissue, leading to increased bone fragility that results in fractures. Pharmacological therapy is aimed at decreasing the risk of fracture, mainly correcting the imbalance between bone resorption and formation at the level of bone remodeling units. Anabolic therapy has the capability to increase bone mass to a greater extent than traditional antiresorptive agents. The only currently available drug licensed is parathyroid hormone 1-34 (teriparatide); new drugs are on the horizon, targeting the stimulation of bone formation, and therefore improving bone mass, structure and ultimately skeletal strength. These are represented by abaloparatide (a 34-amino acid peptide which incorporates critical N-terminal residues, shared by parathyroid hormone and parathyroid hormone-related protein, followed by sequences unique to the latter protein) and romosozumab (an antibody to sclerostin). In the future, the availability of new anabolic treatment will allow a more extensive utilization of additive and sequential approach, with the goal of both prolonging the period of treatment and, more importantly, avoiding the side effects consequent to long-term use of traditional drugs.