Comparing Pump With Subcutaneous Injection Delivery of PTH 1-34 in the Management of Chronic Hypoparathyroidism

Overview

This study will evaluate the safety, biological activity, and pharmacokinetics of PTH delivered by subcutaneous injection compared with an infusion pump. We anticipate pump delivery of PTH will be more physiologic because it mimics normal parathyroid gland secretion of PTH. We expect that pump delivery will simultaneously normalize blood and urine calcium, phosphorus and magnesium levels with minimal or no fluctuations throughout the day. Pump therapy will require lower PTH doses and should normalize markers of bone turnover. We expect the improved metabolic control during pump therapy will be especially evident in patients with more severe forms of hypoparathyrodism where there is an unmet need for improved therapy.

Prior studies (92-CH-0011) have been important in establishing synthetic human parathyroid hormone 1-34 (PTH) as a beneficial treatment for hypoparathyroidism, superior to conventional therapy with calcium and calcitriol. We are conducting a randomized crossover study comparing twice-daily subcutaneous injections vs. PTH pump therapy. We hypothesize that pump delivery of PTH 1-34, compared to twice-daily administration, will provide smoother metabolic control of serum mineral levels and normalization of urine mineral excretion. The two arms will be divided into an inpatient and an outpatient phase. There will be three inpatient admissions, baseline, 3 months, and 6 months. Subjects will be randomized to either pump therapy or to twice daily injections at the beginning of the study and will cross over to the alternate PTH delivery system (injections vs. pump) at the conclusion of the initial 3-month treatment period. Patients between 10 and 70 years of age who have had chronic hypoparathyroidism for at least 1 year may be eligible for this study. Participants have two 10- 12-day hospital admissions and one 5-day admission. The first two inpatient admissions are separated by 3-month outpatient periods. Outpatient monitoring will require weekly blood tests and monthly urine tests to monitor mineral levels. After third hospital admission, patients will be placed on conventional therapy.