Natpar for Hypoparathyroidism Gets Green Light in Europe

Lisa Nainggolan

February 24, 2017

Recombinant human parathyroid hormone (Natpar, Shire Pharmaceuticals Ireland) has been recommended for conditional approval in the European Union by the European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP) for the treatment of patients with chronic hypoparathyroidism who cannot be adequately controlled with standard therapy of calcium and vitamin D.

It will be the first approved parathyroid hormone replacement therapy for this rare condition in the European Union.

Conditional approval allows EMA to recommend a medicine for marketing authorization before all data from clinical trials become available, "if the benefits of making this medicine available to patients immediately outweigh the risks inherent in the lack of comprehensive data," the agency notes.

In hypoparathyroidism, the parathyroid glands in the neck produce too little parathyroid hormone, in most cases because of damage to the glands during surgery and more rarely as a result of autoimmune or congenital diseases. 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 is a hormonal injection administered once daily and is identical to human parathyroid hormone. It 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 same product was approved in the United States, as Natpara 2 years ago, in January 2015.

Manufacturer Must Conduct Postmarketing Study

The EMA notes that 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, 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 with 2.5% of participants who received the placebo treatment.

As part of the conditional marketing authorization, Shire Pharmaceuticals is required to conduct a 26‑week clinical trial to further study the safety and efficacy of the medicine, confirm the dosing schedule, and assess the effects of treatment on symptoms of the disease and on patients' quality of life, the agency notes.

The study will also look at how calcium and phosphate are processed in the body during treatment.

Because hypoparathyroidism is rare, Natpar received an orphan designation from the Committee for Orphan Medicinal Products (COMP) in 2013. Orphan designation is the key instrument available in the European Union to encourage the development of medicines for patients with rare diseases, and orphan designation qualifies medicines for 10 years of market exclusivity.

The opinion adopted by the CHMP at its February 2017 meeting "is an intermediary step on Natpar's path to patient access," notes the EMA.

The CHMP opinion will now be sent to the European Commission for the adoption of a decision on an European Union-wide marketing authorization. Once a marketing authorization has been granted, decisions about price and reimbursement will take place at the level of each member state, taking into account the potential role/use of Natpar in the context of the national health system of that country

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