GlaxoSmithKline's Diabetes Drug Avandia Draws More Scrutiny in Europe

Problems for GlaxoSmithKline's (GSK) diabetes drug Avandia seem to be getting worse. The European Medicines Agency said Friday it's launching a new review of Avandia's benefit-risk profile following new data on the possibility of cardiovascular problems.

Avandia has been in the crosshairs of scientists, regulatory agencies and even U.S. senators in the past year. The EMA decision only adds to the already existing pressure. GSK shares tumbled 2.5% in premarket trading.

Last month, two new studies linked rosiglitazone, or Avandia, to heart attacks and other cardiovascular complications. The authors of the studies said the results should prompt regulators to pull the drug from the market. A U.S. Food and Drug Administration panel is indeed going to study the data next week.

A New Reevaluation

Now, the EMA will also be considering Avandia following the recent studies. Already, the product has been reviewed several times by the agency's Committee for Medicinal Products for Human Use, which has updated the product information to include warnings on the use of these medicines in patients with heart problems. In 2008, the committee concluded that "rosiglitazone retained a small, if diminishing, place in diabetes type 2 therapy." Then again, it looked at the drug earlier this year.

The committee is now assessing the new data and will be discussing the issue at its next plenary meeting, July 19-22.

"Once all relevant data on the benefits and the risks of rosiglitazone have been looked at, the CHMP will issue an opinion on whether or not the marketing authorisations for these medicines should be revoked, suspended or changed," the EMA said in a statement.

The EU has authorized rosiglitazone on its own is as Avandia, in combination with metformin as Avandamet, and with glimepiride as Avaglim.

"Insufficient Data"?

GSK has defended Avandia, saying two heart associations have found that "Insufficient data exist to support the choice of" one treatment over the other. Still, sales of Avandia, which topped $2.6 billion in 2006, fell to $1.2 billion in 2009 after the FDA added a label warning regarding the elevated cardiac risk.

Judging from investors' reaction, the pressure on this drug is likely to keep mounting.