British drug maker GlaxoSmithKline reported Thursday that its controversial diabetes drug Avandia is under investigation by federal and state law enforcement officials in the U.S.
The announcement came less than a month after the Food and Drug Administration issued severe restrictions on use of Avandia because of its links to heart attack. Regulators in Europe pulled the drug off the market altogether.
Glaxo said it received a subpoena from Department of Justice, which is investigating the development of marketing of Avandia. The company received similar requests for information from attorneys general in several states.
"These enquiries are at an early-stage, and GSK is cooperating with these offices," the company stated in its third-quarter earnings filing.
Avandia was once Glaxo's third best-selling product, with over $3 billion in sales in 2006, but it has become a major liability since 2007 when its heart risks were first publicized.
More than 2 million patients in the U.S. filled prescriptions for Avandia last year, though that number is expected to shrink under new FDA restrictions. The agency announced in September that patients would have to sign a waiver saying they understand Avandia's risks before receiving the drug. The drug will be available only to patients who can't control their blood sugar with alternate medications.
Glaxo CEO Andrew Witty said on a call with analysts that the company also faces new lawsuits from patients who took Avandia, though he did not specify how many.
Analysts reported earlier this year that the company had settled the bulk of an estimated 13,000 personal injury lawsuits filed by Avandia patients.
The probe by federal and state prosecutors follows years of investigation by congressional staffers into the company's handling of the drug.
Earlier this year the Senate Finance Committee issued a report concluding that Glaxo knew about the heart risks of its drug years before they were made public, and withheld important data from the FDA.
London-based Glaxo has said that the Senate report "mischaracterizes and distorts" the company's record.