May 1 Reuters Ascendis Pharma AS said on Monday the U.S. Food Drug Administration had declined to approve the Danish drugmaker39;s experimental therapy to treat adult patients with a hormone disorder called hypoparathyroidism, citing concerns linked to manufacturing control of the drug and device combination.

The company39;s U.S.listed shares surged 19 in premarket trade as the agency did not express concerns about the clinical data submitted and did not seek fresh preclinical or latestage trials in a socalled complete response letter.

Ascendis said it would request a meeting with the FDA as soon as possible on the best path forward.

Shares have lost about 35 of their value through Friday39;s close of 69.96 since the FDA early last month identified unspecified deficiencies in the company39;s application for approval of the therapy, TransCon PTH.

In a note on Friday, TD Cowen analyst Yaron Werber raised concerns about the lack of clarity around the FDA decision following the Ascendis39; postearnings conference late Thursday.

He said the stock would slump if the FDA sought another preclinical or clinical study as this would delay approval by 1.52 years. He expected the stock to advance if the delay was to the end of this year.

Werber has estimated peak sales of 827 million euros 911 million for the therapy in case of an approval this year, but anticipates it crossing 1 billion euros if the uptake is strong.

TransCon PTH is being developed as a oncedaily therapy to…