Drug giant accused of using stand-over tactics about Avandia

The controversy surrounding GlaxoSmithKline's (GSK) diabetes drug Avandia has been exacerbated by claims from a medical expert that he was threatened with a $4bn lawsuit to try to silence his criticisms of the company's controversial diabetes drug.

John Buse testified at a Senate hearing that he felt so intimidated by company employees that he sent a desperate letter to a board member asking him to "call off the dogs".

Dr. John Buse says in 1999 after drawing attention to a trend in heart problems among patients using Avandia, he was contacted by GSK.

He says threats and a smear campaign against him began after he publicly warned that there may be heart risks associated with Avandia, then a brand new drug.

Dr. Buse who is a respected diabetes researcher is about to take over as president of the American Diabetes Association.

He believed salesmen at GSK were exaggerating the benefits of Avandia and that there should have been a proper study into the heart risks of the drug.

At the time GSK dismissed him as a "liar" and impugned his integrity and matters came to a head when he was threatened with the lawsuit.

Eight years down the line, with a million Americans now taking Avandia on a regular basis, a study last month concluded that the pill significantly raises the risk of heart attacks and fatal heart problems.

Buse says though he eventually signed a clarifying statement with the company that was used to ease concerns from investors, a year later he sent a letter to the Food and Drug Administration raising the same concerns.

GSK is appearing before the Senate committee to defend Avandia's safety and dispel criticisms that it underplayed the potential side effects and deliberately failed to launch the right studies to check the risks.

GSK maintains the drug is as safe as other diabetes medications.

Henry Waxman, a Democrat Senator for California, who is a frequent critic of FDA and the chair of the Oversight committee, prompted the hearing after an analysis in the New England Journal of Medicine concluded Avandia could raise patients' risk of heart attack by more than 40 percent.

Waxman says FDA officials failed to act on warnings from Buse and others in the eight years since Avandia was approved.

Waxman is among a group of House Democrats who want to give FDA more powers to regulate drug companies.

The Food & Drug Administration (FDA) is now requesting that Avandia and similar alternative drugs carry enhanced warnings on the risk of heart problems, and GSK said yesterday that it was talking to the agency about the wording to be included in a prominent black box on the label.