The firm, which developed anti-depressant medicine Citalopram, stands accused of hindering the entry of a generic form of the drug onto European markets. Lundbeck said it will cooperate with the investigation but insists it has broken no laws.
Antitrust officials in Brussels said it would look at whether the company broke EU rules on restrictive business practices and abuse of a dominant market position.
"The Commission in particular intends to investigate unilateral behaviour and agreements by Lundbeck which may hinder the entry of generic Citalopram into markets in the European Economic Area," the EU executive said in a statement.
It said that knowledge acquired during the pharmaceutical sector inquiry, specifically on ways in which originator companies obstruct the availability of generics, had helped inform its decision to target Lundbeck.
The Commission said its investigation would be dealt with as a matter of priority, although it did not set a timeline for concluding the probe.
A spokesperson for the company said it has "nothing to hide" and added that "all relevant national and EU competition legislation" had been abided by.
Lundbeck said the investigation would have no influence on its financial results for 2009. Its shares traded up 1.8% in the immediate aftermath of the announcement in Brussels.
The antitrust arm of the EU executive has repeatedly locked horns with big business in recent years, notably in its high-profile case against Microsoft and a separate decision to impose a record €1 billion fine on Intel for competition breaches (EurActiv 14/05/09).
