Teriparatide: A review

Abstract

Background: Traditionally, the management of osteoporosis in men and women has included the use of antiresorptive agents in combination with calcium and vitamin D supplementation. The mechanism of action of teriparatide is unique in that it possesses anabolic properties and therefore builds bone. Since the approval of teriparatide in the United States in 2002, a great deal of interest regarding its use in osteoporosis has developed. Objectives: This article reviews the information available on the new recombinant human parathyroid hormone teriparatide (hPTH [1–34]), including its clinical pharmacology, mechanism of action, pharmacokinetic properties, clinical efficacy, safety profile, potential drug interactions, contraindications and warnings, dosage and administration, and pharmacoeconomics. Methods: The articles included in this review were identified through searches of PubMed and MEDLINE (1966–December 2003) and International Pharmaceutical Abstracts (1970–December 2003). Search terms included teriparatide, Forteo, recombinant human parathyroid hormone (1–34), and osteoporosis. The references of the identified articles were reviewed for additional publications. Specific product information was also obtained from the manufacturer of teriparatide. Results: Teriparatide has been studied in postmenopausal women with osteoporosis, drug-induced osteoporosis (specifically, corticosteroid-induced osteoporosis), and men with osteoporosis. The data available from various clinical trials have shown an increase in both bone mineral density (BMD) and bone mineral content (BMC) with the use of teriparatide compared with placebo. One study found that women treated with the 20-μg dose and the 40-μg dose were 35% and 40%, respectively, less likely to have one or more new nonvertebral fractures compared with placebo ( P = 0.02). Another study compared the use of daily teriparatide 40-μg injections versus oral daily alendronate. Results showed that the incidence of nonvertebral fractures was significantly lower in the teriparatide group than the alendronate group ( P < 0.05). A study using 20- and 40-μg daily injections of teriparatide was performed in men with osteoporosis. There was a statisticatly significant increase in lumbar spine BMD of 5.9% in the 20-μg group and 9.0% in the 40-μg group (both, P < 0.001). In the femoral neck, a 1.5% increase in BMD occurred in the 20-μg group ( P = 0.021) and a 0.9% increase in the 40-μg group ( P < 0.001). A limited number of studies are available assessing the combination of antiresorptive medications and teriparatide; however, the available data suggest that the effects of teriperatide do not require prior stimulation of bone resorption. Conclusions: Teriparatide has been shown clinically to improve BMD and BMC in postmenopausal women and in men. Because of its anabolic capabilities, teriparatide can be used as an alternative to the traditional therapies that are currently available for the treatment of osteoporosis, with scheduled monitoring for adverse effects such as hypercalcemia and urinary calcium excretion. In 1 study, mild hypercalcemia was seen most often 4 to 6 hours after SC injection of teriparatide before returning to normal. Urinary calcium was observed to increase by 30 mg/d (0.75 mmol/d) with teriparatide.