Risks of Glaxo diabetes drug still unclear: FDA

By Lisa Richwine and Susan Heavey

WASHINGTON (Reuters) - The potential heart risks of GlaxoSmithKline Plc's diabetes drug Avandia are still not clear, the head of the U.S. Food and Drug Administration told lawmakers who questioned the agency's oversight of the widely used pill on Wednesday.

At a House of Representatives committee hearing, Democrats asked why the FDA had failed to request a study years ago that would have shed more light on Avandia's effect on the heart.

Republicans, meanwhile, said the spotlight on the drug was political rather than scientific.

FDA Commissioner Andrew von Eschenbach said all studies to date "are inconsistent and conclusions are not clear" on Avandia's possible contribution to heart attacks.

"That means FDA is not at present justified in taking additional regulatory action or recommending that patients stop using it," he told the House Oversight and Government Reform Committee.

Von Eschenbach did say the agency has asked for a stronger "black box" warning about another heart risk -- congestive heart failure -- on the labels of Avandia and Actos, a competitor made by Takeda Pharmaceutical Co. Ltd. . Both drugs now have a less prominent warning about that risk.

"Despite these existing warnings, these drugs were being prescribed to patients with significant heart failure," von Eschenbach said.

Takeda said it would add a boxed warning. Glaxo said it was discussing the request with the FDA.

A furor erupted last month when a Cleveland Clinic analysis linked Avandia to a 43 percent higher chance of having a heart attack. The study sparked an outcry from lawmakers who are considering legislation to improve the FDA's drug safety monitoring.

Millions of patients take Avandia, and sales topped $3 billion last year. But total prescriptions have fallen nearly 25 percent between May 18 and June 1, according to Verispan data. Total prescriptions for Actos have risen nearly 14 percent.

Glaxo shares fell 44 cents on Wednesday to close at $51.46 on the New York Stock Exchange. They are down nearly 11 percent since the Cleveland Clinic study was issued on May 21.

LOOKING FOR ANSWERS

Lawmakers are not trying to decide if Avandia might do more harm than good, said committee chairman Rep. Henry Waxman.

"I'm interested in why ... eight years after Avandia's approval for market that doctors and their patients still don't have a clear answer," the California Democrat said.

He said the FDA had failed to request a post-marketing study that would determine Avandia's cardiovascular risks, as an agency reviewer had suggested.