Novo Nordisk shares are taking a beating Monday.

The stock price of Danish drug firm Novo Nordisk, which operates a big insulin manufacturing plant in Johnston County, plunged Monday on news that the FDA has rejected two proposed once-per-day insulin drugs.

The company announced Monday that it received the so-called complete response letter on Friday.

Novo Nordisk fell as much as 17 percent.

Novo Nordisk, which is the world’s largest insulin maker, say regulators are seeking a study to assess heart risk, dealing the company a setback in its contest with Sanofi for the diabetes market.

Tresiba contains long-acting insulin, and Ryzodeg contains both long- and short-acting insulins.

The FDA said Tresiba, can’t be approved without more data on heart safety. Novo Nordisk said it’s unlikely to be able to provide the information next year.

“We are convinced that Tresiba and Ryzodeg offer significant benefits for people who require insulin”, said Lars Rebien Sorensen, chief executive officer of Novo Nordisk, in a statement. “We are surprised and disappointed to receive this letter, but we acknowledge this decision by the FDA and will work with the agency to determine the best path forward to completing the review.”

The FDA said Novo Nordisk also must resolve a warning letter on one of its plants before Tresiba is approved.

The plant is located in Denmark. 

In November, panel of federal health advisers recommended that the government approve degludec. The FDA is not required to follow the group’s advice, but it often does.

Diabetics either do not produce enough of the hormone insulin or do not use it efficiently, allowing excess sugar, or glucose, to accumulate in the blood.