Hypoparathyroidism is one of the few remaining hormone deficiency states without an approved replacement therapy. Because the primary role of parathyroid hormone is to maintain normal calcium levels in blood, the major consequence of its absence is low circulating calcium levels (hypocalcemia), which can cause tingling of the hands, fingers, and mouth, serious muscle cramping or, in extreme situations, to tetany or convulsions. The goal of currently available treatments for hypoparathyroidism, which include life-long high-dose oral supplementation with calcium and active vitamin D metabolites or analogs, is to reduce the severity of symptoms; however, hypoparathyroidism and the use of oral calcium and vitamin D analogs/metabolites for symptom control can contribute to organ damage and calcification, which is particularly evident in the kidneys. NPS has estimated that approximately 65,000 patients suffer from hypoparathyroidism in the U.S.

Patient enrollment has begun in a Phase 3 registration study, known as REPLACE, evaluating NPSP558, our proprietary recombinant, full-length (1-84), human parathyroid hormone, for the treatment of hypoparathyroidism.  The primary objective is to demonstrate, over a 24-week treatment period, that once-daily subcutaneous dosing with NPSP558 at doses of 50µg, 75µg or 100µg is a safe and effective hormone replacement therapy for the treatment of patients with hypoparathyroidism.  For more information on REPLACE, please click here.