Vanda Pharmaceuticals (VNDA) shares tumbled 15% premarket Thursday after the biopharmaceutical company said the US Food and Drug Administration declined to approve its new-drug application for tradipitant to treat symptoms in gastroparesis.

Vanda said the FDA "generally disregarded the evidence provided and instead suggested that Vanda conduct additional studies with a design and duration inconsistent with the advice of key experts in the field and not appropriate based on the scientific understanding and natural course of the disorder."

Vanda also said the FDA's decision exceeded the time limit specified by the Food Drug and Cosmetic Act, which requires the regulator to review an NDA and provide either an approval or an opportunity for a hearing within 180 days of submission. "In this case the FDA failed to do either," Vanda said.

The FDA did not immediately respond to a request for comment from MT Newswires.

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