Future therapies

This chapter focuses on two classes of emerging therapies, inhibitors of cathepsin K (CatK) and of sclerostin, and also focuses on single drugs in each of these classes that have recently completed phase III registration trials. A third new drug, abaloparatide, has recently received regulatory approval in the United States. The chapter considers some additional therapies targeting different molecular pathways. Targeted disruption of the CatK gene in mice results in a phenotype with an osteosclerotic skeleton with increased trabecular and cortical bone mass of good quality. Compared with normal animals, CatK‐deficient mice have increased bone strength at the vertebral body and femoral midshaft. Sclerostin inhibits osteoblast activity by interrupting the Wnt signaling pathway. Inhibiting sclerostin activity with an antisclerostin antibody in animals demonstrated the potential of this strategy to improve bone mass and structure. The novel anabolic effects of antisclerostin antibody therapy offer great promise for the treatment of osteoporosis.