US diabetes specialist claims GSK made threats over Avandia

The controversy over GlaxoSmithKline's (GSK) diabetes drug, Avandia (roseglitazone), has taken another surprise turn, when a medical expert in the US accused the UK's largest pharmaceutical firm of trying to silence him when he questioned the drug's safety.

Dr John Buse, who is a diabetes expert from the University of North Carolina, said that he had received telephone calls from GSK executives when the drug went on sale in 1999, claiming his "actions were scurrilous enough to attempt to hold me liable for a loss in market capitalisation".

Buse, who disclosed the threats of legal action in a written testimony submitted for a congressional hearing on the drug's safety on 6 June, said that later he had signed a statement drafted by GSK to ease concerns that his warnings had raised among shareholders.

GSK's CEO, JP Garnier, strongly rejected Buse's claims: "We don't threaten people. Dr Buse did issue a correction. There are no hard feelings."

PMLive reported last week that Buse had written a letter to the FDA warning that the drug might increase the risk of heart attacks. He also criticised GSK's "blatant selective manipulation of data", which he said had "understated the drugs risks and overstated its benefits".

Published research in the New England Journal of Medicine (NEJM), which claimed Avandia caused cardiovascular problems, has prompted the US House of Representatives' Committee on Oversight and Government Reform to convene a hearing into the FDA's role in evaluating the safety of Avandia.

Henry Waxman, the committee's chairman, has criticised FDA Commissioner, Andrew von Eschenbach, for failing to request specific research into Avandia's cardiovascular damage profile after Buse and, later, the World Health Organisation, gave warnings of a potential connection. The FDA has been under increased scrutiny over its drug safety procedures.