Zelos Therapeutics is developing a novel peptide analog of the parathyroid hormone (PTH) for postmenopausal osteoporosis

Zelos Therapeutics (www.zelostherapeutics.com) is developing a novel peptide analog of the parathyroid hormone (PTH) for postmenopausal osteoporosis, called Ostabolin-C (in Phase II trial).

PTH has two important signaling domains, the first domain activates adenylate cyclase, and the second domain stimulates protein kinase C activity. Studies invitro and animal models revealed that the adenylate cyclase signaling component was responsible for the bone-stimulating activity of PTH. We realized that modulating adenylate cyclase had important implications for osteoporosis therapy, says Paul Morley, Ph.D., scientific founder and CSO of Zelos Therapeutics.

Ostabolin-C activates bone-stimulation mechanisms, but does not affect bone resorption activity. Bone resorption leads to the side effects observed with existing injectable PTH drugs. Also, these injectables are more effective at reducing vertebral fractures than fractures of the hip or wrist. We anticipate that our peptide drug will have a lower incidence and severity of side effects and induce the formation of better quality bone at all of these sites, says Dr. Morley. Zelos has partnered with Nektar (www.nektar.com) to develop a pulmonary delivery formulation of Ostabolin-C.