Shares of Novo Nordisk (NVO) fell more than 13% on Monday morning after the diabetes-focused drug maker said its new, highly-anticipated insulin drugs Tresiba and Ryzodeg failed to garner enough support from U.S. regulators.  

The U.S. Food and Drug Administration issued a Complete Response Letter to Novo Nordisk on Friday saying the application cannot be approved in its current form, and requested additional cardiovascular data.

The setback is expected to delay the release of the drug. Novo had been hoping to receive U.S. approval in 2013, however, the company on Monday said it does not expect to meet the FDA’s demands this year.

“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,” Novo CEO Lars Rebien Sørensen said in a statement.

Shares of the Danish drug maker tumbled more than 13% $166.61 Monday morning.

Novo Nordisk’s new drugs are expected to meet widening demand for insulin. The company filed a New Drug Application for them in September of 2011. 

Follow Jennifer Booton on Twitter at @Jbooton