Full length parathyroid hormone, PTH(1-84), for the treatment of severe osteoporosis in postmenopausal women.

OBJECTIVE

To review and analyse the evidence supporting the use of full length parathyroid hormone, PTH(1-84), in the treatment of osteoporosis based on a search of several literature sources; articles selected for review were published between 1990 and 2008.

BACKGROUND

PTH(1-84) is approved for the treatment of osteoporosis in postmenopausal women at high risk of fracture in Europe. It was well tolerated in clinical trials and demonstrated bone building properties and fracture prevention particularly for the lumbar spine in the treatment of postmenopausal women.

RESULTS

The TOP clinical trial showed that PTH(1-84) treatment for 18 months resulted in a 61% reduction (p = 0.001) in new vertebral fracture incidence when compared with placebo and reduced the risk of a first vertebral fracture by 68% (p = 0.006) in women without a prevalent fracture at baseline. PTH(1-84) increased bone mineral density (BMD) at vertebral and non-vertebral sites the lumbar spine BMD increasing regardless of T-score, age, prior osteoporosis therapy or number of years post-menopause. The PaTH study showed that treatment with PTH(1-84) for 12 months increased BMD at the trabecular spine and hip. Lumbar spine BMD gains were largest with sequential administration of PTH(1-84) followed by alendronate but were smaller with concurrent administration involving anabolic and antiresorptive agents. Lumbar spine BMD increases were also seen in trials involving PTH with raloxifene and PTH in combination with hormone replacement therapy.

CONCLUSIONS

PTH(1-84) has demonstrated effective bone building qualities and extends the therapeutic options available to osteoporotic women. The use of PTH(1-84) followed by sequential administration of an antiresorptive has proved effective at increasing trabecular BMD and points towards new treatment regimens offering improvements in BMD and fracture prevention.