NPS Pharmaceutical, Inc., headquartered in Bedminster, New Jersey, USA, won FDA approval on January 23, 2015 for Natpara, the first bioengineered replacement therapy cleared for U.S. marketing to treat hypoparathyroidism. FDA has granted an orphan-drug designation for Natpara in 2007. And according to NPS Pharmaceutical, Natpara is expected to be available in the second quarter of 2015.
Hypoparathyroidism is a rare endocrine disorder, which the body secretes abnormally low levels of parathyroid hormone (PTH), resulting in low calcium levels (hypocalcemia) in your blood and bones and increased levels of serum phosphorus (hyperphosphatemia). It affects approximately 60,000 people in the US (J Bone Miner Res. 2013 Dec;28(12):2570-6.). PTH is secreted by the parathyroid gland, which is located behind the thyroid gland. PTH functions to control homeostasis of calcium and phosphorus via regulating calcium release from the bone, excretion from the kidney, and absorption from the intestines. The major causes for hypoparathyroidism include autoimmune disease, acquired hypoparathyroidism (for instance, due to surgery), extensive cancer radiation treatment near the face and neck, hereditary hypoparathyroidism and low levels of blood magnesium.
There is no effective treatment for hypoparathyroidism currently and the disease is managed clinically by calcium and vitamin D supplementation. This management has common gastrointestinal side effect and some patients fail to respond to the treatment. In addition, prolonged treatment sometimes can lead to calcium-phosphate deposit in the kidneys, heart and brain causing various complications for patients. Importantly, another function of PTH is to convert vitamin D into its active form to promote the absorption of oral calcium supplementation and the current treatments of hypoparathyroidism do not address this underlying cause. Natpara is a recombinant human PTH, the first kind of biologic to treat hypoparathyroidism. It can be injected subcutaneously to act as natural PTH to alleviate the symptoms associated with hypoparathyroidism, treat the root cause of this rare disease and restore the balance of calcium/phosphorus in patients.