Parathyroid hormone (1-84) and treatment of osteoporosis

To present the chemistry, pharmacology, and pharmacokinetics of parathyroid hormone (PTH) (1-84) and review the available clinical trials that evaluate its efficacy and safety; clinical applicability of this agent and its relationship to other Food and Drug Administration (FDA)-approved medications for treatment of osteoporosis are also discussed.

A MEDLINE search (1996-December 2004) was completed, along with a review of information obtained from the manufacturer, NPS Pharmaceuticals. Key search terms included parathyroid hormone, PTH (1-84), and ALX 111.

Studies were selected based on their relevance and availability. Pertinent information, including objectives, design, demographics, outcomes, adverse events, dosing strategies, and therapeutic controversies, was extracted.

PTH (1-84) is being developed for treatment of osteoporosis. Recent studies have shown that, when administered intermittently as a subcutaneous injection, PTH (1-84) produces an increase in bone mineral density and prevents vertebral fractures. The fact that this agent contains the C-terminal region of PTH may differentiate it from PTH (1-34), teriparatide, which is approved by the FDA for treatment of osteoporosis. Further trials are necessary to determine the role of PTH (1-84) in combination with other treatments for osteoporosis and/or the order in which PTH (1-84) is given with these other agents. There are currently no comparative trials with other osteoporosis treatment modalities.

PTH (1-84), when given intermittently as a subcutaneous injection, appears to be a safe and efficacious treatment option for osteoporosis. Further trials are needed to determine its specific place in therapy compared with other treatment options.