NPS Pharma Hormone Drug Wins Shaky Endorsement From FDA Panel

BEDMINSTER, NJ (TheStreet) -- NPS Pharmaceuticals (NPSP) shares are down 11% in early Monday trading following a rough outing for its hormone replacement therapy Natpara at an FDA advisory panel on Friday. 

Independent experts on the FDA panel voted 8-5 to recommend approval of Natpara as a new treatment for hypoparathyroidism, but concerns and complaints about the drug's clinical benefit and safety were raised repeatedly during the day-long meeting. FDA is expected to make an approval decision on Natpara by Oct. 24, but the lukewarm tone of Friday's panel plus unresolved issues might compel the agency to extend its review, approve the drug with restrictions, or in the worst case, reject the drug and NPS Pharma for additional clinical data.

Investors went into Friday's Natpara panel with high expectations. The slide in NPS Pharma shares Monday reflect a cooling opinion about the drug's regulatory and commercial prospects, particularly given the company's $3.4 billion market value. 

Hypoparathyroidism is a relatively rare condition in which a person is unable to produce sufficient levels of parathyroid hormone, which leads to low levels of calcium and excess levels of phosphorus in the body. Patients with hypoparathyroidism must take calcium and other supplements for the rest of their lives. Natpara is an injection designed to replace the missing parathyroid human and reduce the amount of supplements patients require. 

During Friday's panel, patients suffering from hypoparathyroidism who participated in the Natpara clinical trial said the drug improved their quality of life, and they urged the experts to recommend its approval. Many of the experts said the patient testimony persuaded them to vote yes on Natpara, even while still having lingering concerns. NPS Pharma tested Natpara using a single daily dose, but the FDA and panel experts said more frequent dosing of the drug might be more effective. The panel also raised concerns about the long-term safety of Natpara, which has been tied to a greater risk of osteosarcoma and an inability to control calcium levels in the blood. 

NPS Pharma was expecting a more positive outcome from Friday's FDA panel. The company issued a press release Friday night announcing experts voted "unanimously 8-5" that the Natpara clinical data supported approval. Later, the company issued a corrected press release deleting "unanimously." 

"We are very pleased with the Committee's vote. Their recommendation reinforces our belief in the favorable benefit-risk profile of Natpara and its potential as a long-term treatment option for Hypoparathyroidism," said NPS Pharma CEO Francois Nader, in a statement. The company said Natpara will be available commercially within weeks of approval.

Whether Natpara is approved on Oct. 24 or is delayed, possibly with restrictions, remains to be seen.

NPS shares are down 11% to $28.87.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.

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