Shares in Novo Nordisk A/S (NOVO-B.KO) slumped Friday amid fears that U.S. regulators would delay the launch of its potential blockbuster diabetes drug Liraglutide.

Late Thursday, an expert panel of the U.S. Food and Drug Administration came to a split vote on whether data on a type of thyroid tumors seen in rodent studies permitted marketing of the drug.

Despite the setback, the Danish pharmaceutical company's chief executive Lars Rebien Sorensen said on a conference call Friday that Novo Nordisk is still committed to bringing Liraglutide to the market. He said the company recognizes the FDA panel's concerns, and will continue to work closely with the regulator over the next months.

The FDA is widely expected to take the expert panel's opinion into account when it later decides on whether to approve a launch in the U.S., which Novo Nordisk sees as Liraglutide's most important potential market.

Novo Nordisk Chief Financial Officer Jesper Brandgaard said it's now uncertain whether Liraglutide will be launched by mid-2009, as was previously expected by the company, but added that the immediate financial impact in 2009 of a delayed launch will be limited.

At 0926 GMT, shares in Novo Nordisk were down 10% at DKK252.50, underperforming a 2.1% drop in the wider market in Copenhagen.

Analyst Rune Majlund Dahl at Sydbank said investors fear that the FDA may demand pre-approval safety tests for Liraglutide, which may delay the drug's launch and destroy its perceived first-mover advantage against Eli Lilly's (LLY), Amylin's (AMLN) and Alkernes' (ALKS) competing diabetes drug Byetta LAR, which is seen being launched by mid-2010. Dahl said a complete block of Liraglutide is unlikely, but that the drug's commercial appeal may be hit if it is labelled with a cancer warning. Majlund Dahl maintained his overweight rating for the stock.

Still, UBS reiterated its buy rating for Novo Nordisk and said its current share price already overly discounts a negative outcome for Liraglutide. UBS predicted that the FDA will make its decision on the drug by mid-2009.

Liraglutide, also known under the marketing name Victoza, is seen as Novo Nordisk's most important drug under development. Jyske Bank has previously predicted its sales to peak in 2015 at 8.2 billion Danish kroner ($1.5 billion), compared with Novo Nordisk's total group sales of DKK46 billion in the full year 2008.

Company Web site: http://www.novonordisk.com

-By Gustav Sandstrom, Dow Jones Newswires; +46-8-5451-3099; gustav.sandstrom@dowjones.com