Novel Parathyroid Hormone Replacement Therapy
First hormone replacement therapy for parathyroid disorder
Natpar (parathyroid hormone) is proposed as a treatment for patients with chronic hypoparathyroidism who cannot be adequately controlled with standard treatment with calcium and vitamin D. It is the first approved replacement therapy with parathyroid hormone for this rare condition.
Hypoparathyroidism is a hormone disorder where the parathyroid glands in the neck produce too little parathyroid hormone, in most cases because of damage to the parathyroid glands during surgery. This results in too little calcium and too much phosphate in the blood, which affects the normal functioning of nerves and muscles leading to symptoms such as tingling sensations and muscle spasms or even seizures and heart rhythm disorders. In the longer term, uncontrolled hypoparathyroidism increases the risk of bone fractures and calcium deposits, particularly on the kidney, brain and eye lens.
Natpar, a hormonal injection administered once daily, is identical to human parathyroid hormone. Injection of Natpar replaces to some extent the missing hormone in patients with hypoparathyroidism, thus helping to restore calcium and phosphate levels in those patients where standard therapy with calcium and vitamin D is insufficient or poorly tolerated. Currently, no treatment options are available for these patients.
The safety and effectiveness of Natpar were evaluated in a clinical trial of 124 participants who were randomly assigned to receive Natpar or a placebo (dummy treatment), in addition to the standard treatment with calcium and vitamin D. The trial was designed to determine whether Natpar can be used to help reduce the amount of calcium or vitamin D taken by the participants, while maintaining acceptable calcium and phosphate serum levels. Results showed that 54.8% of participants treated with Natpar were able to reduce the doses of calcium and vitamin D supplements by more than 50% while maintaining acceptable blood-calcium levels, compared to 2.5% of participants who received the placebo treatment.
Surgical hypoparathyroidism is the most common form of the disease.Image is of a patient with calcium deficiency and a finding of the “bell hops hand” due to low calcium.