TEXT OF INTERVIEWSCOTT JAGOW: Drugmaker GlaxoSmithKline faces some serious questions about one of its top-selling drugs. A study in the New England Journal of Medicine says this diabetes drug, Avandia may cause heart problems. Sound familiar? That was the conclusion about Merck’s painkiller Vioxx. Glaxo’s shares are tumbling overseas. Our correspondent Stephen Beard joins us from London with more. Stephen?

STEPHEN BEARD: The shares fell a further three percent in London today, extending yesterday’s fall of 5 percent. The company’s stock market value has now fallen by the best part of $13 billion. The trigger, this research by the Cleveland Clinic in Ohio suggesting that Glaxo’s diabetes drug Avandia raises the risk of heart attack by 40 percent.

JAGOW: Yeah I was reading that the same guy who found problems with Vioxx also found problems with this drug. Do we have any sense at this point whether or not the fallout could be on that kind of scale like Vioxx?

BEARD: Well this is Glaxo’s second best-selling drug. One analyst here says unless this research can be refuted, this is going to be very seriously damaging for one of the cornerstones of the company.

JAGOW: And what is the FDA saying at this point?

BEARD: Well the FDA is saying that it’s keeping an open mind on this. It says that this research conflicts with other studies. It’s not asking Glaxo to take any action, it’s merely urging patients with known heart problems to consult their doctors about taking Avandia. And Glaxo of course is standing by its drug. It says that this research is based on incomplete evidence and doubtful methodology.

JAGOW: OK Stephen Beard in London, thanks.

BEARD: OK Scott.