The FDA has approved a once-daily injection of recombinant human parathyroid hormone (Natpara, NPS Pharmaceuticals) to control hypocalcemia in patients with hypoparathyroidism, according to an agency press release.
The FDA granted Natpara orphan drug designation because hypoparathyroidism is a rare condition that affects approximately 60,000 people in the United States. In September 2014, an FDA advisory panel voted 8-5 in favor of its approval for long-term treatment of the condition.
To assess the safety and efficacy of Natpara, the agency considered data from a clinical trial involving 124 participants who were randomly assigned to receive the drug or placebo. Researchers sought to determine if the drug could replace or help reduce the amount of active forms of vitamin D or oral calcium taken by participants.
Forty-two percent of patients treated with Natpara achieved normal blood calcium levels with reduced doses of supplements vs. 3% of those treated with placebo, according to the release.
The most common side effects included sensations of tingling, tickling, pricking or paresthesia as well as low blood calcium, headache, high blood calcium and nausea.
Natpara also carries a boxed warning noting that osteosarcoma has been found in rat studies with the drug, though it is currently unknown whether the drug is linked to the disease in humans. Because of this potential risk, however, the drug is only recommended for patients who are unable to control their hypocalcemia with calcium supplementation and active forms of vitamin D and for whom the benefits outweigh this potential risk.
The agency also stated that Natpara is only available through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS).
“People with hypoparathyroidism have limited treatment options and face challenging symptoms that can severely impact their quality of life,” Jean-Marc Guettier, MD, director of the Division of Metabolism and Endocrinology Products in the FDA’s Center for Drug Evaluation and Research. “This product offers an alternative to patients whose calcium levels cannot be controlled on calcium supplementation and active forms of vitamin D.”