Clinical Trial: The Effects of Alendronate After Cure of Primary Hyperparathyroidism

Study Status: Withdrawn
Recruit Status: Withdrawn
Study Type: Interventional

Official Title: The Effects of Alendronate After Cure of Primary Hyperparathyroidism

Brief Summary:

We are investigating whether, after surgical cure of primary hyperparathyroidism, alendronate provides even greater beneficial skeletal effects than parathyroidectomy alone.

Primary Hyperparathyroidism (PHPT) is a disorder that can be associated with bone loss. After successful surgery for PHPT bone density improves without any treatment. However, it is possible that bone density might improve to an even greater extent if Fosamax is used after the surgical cure. Fosamax is approved by the FDA for the prevention and treatment of osteoporosis, and the goal of this project is to determine whether after successful surgical cure of PHPT, Fosamax is even better for the skeleton than just parathyroid surgery alone.

Detailed Summary:

Study Purpose:

Hypothesis: After successful surgical cure of primary hyperparathyroidism alendronate provides even greater beneficial skeletal effects than parathyroidectomy alone.

Primary hyperparathyroidism (PHPT) is typically a disorder of mild hypercalcemia. Skeletal involvement can be demonstrated when bone densitometry is performed. Effects of excess PTH on bone include preferential involvement of cortical bone (e.g. forearm) and relative sparing of cancellous bone (e.g. vertebral spine). Bone properties, such as bone turnover, size and geometry, are also altered in PHPT. The only cure for PHPT is removal of abnormal parathyroid tissue. In the absence of medical intervention, bone mass increases briskly after successful surgical treatment of PHPT. Parathyroid surgery also promptly reduces bone remodeling, typically increased in PHPT, to normal values. Bone resorption markers fall first, followed by bone formation markers. The difference in time course between the rapid fall in resorption markers and the more gradual fall in formation markers provides a window of time when bone mass increases rapidly. The post-surgical increase in BMD is attributed to a filling-in, or mineralization, of the enlarged, PTH-driven, remodeling space. Whether further gains in bone density could be achieved with more prompt and greater suppression of bone resorption in the postoperative period is unknown. The potent bisphosphonate, alendronate (Fosamax), reduces bone remodeling and enhances secondary mineralization. It has been shown to increase bone density in subjects with PHPT who do not undergo parathyroid surgery. The goal of this project is to test the hypothesis that after successful surgical cure of PHPT, alendronate provides even greater beneficial skeletal effects than parathyroidectomy alone.