Diabetes drug Avandia has FDA split over new concerns about its safety

New federal analyses released Friday raised additional questions about the safety of the controversial diabetes drug Avandia.

The analyses are among more than 700 pages of documents that were posted on the Food and Drug Administration's Web site in advance of a meeting next week of scientific advisers to once again consider whether Avandia should remain on the market.

During a briefing for reporters Thursday, FDA officials cautioned that agency experts remained split over the drug.

"There's not complete unanimity within the FDA about interpretation of these data, and that's one of the reasons we're going to the advisory committee," said Janet Woodcock, director of the FDA's center for drug evaluation and research.

Among the new analyses are critiques of a study known as Record, which the company sponsored and touted as evidence that the drug is safe. Thomas A. Marciniak of the FDA's division of cardiovascular and renal products concluded the company's analysis was flawed and the data show the drug increases the risk for heart attacks. But another analysis by Ellis Unger, a deputy director in FDA's drug division, questioned Marciniak's findings.

Critics said data provide convincing evidence that the drug increases the risk for heart attacks, strokes and death and should be removed from the market.

"What they were able to do in many ways was confirm my worst fears about the drug," said Steven E. Nissen, a Cleveland Clinic cardiologist who first raised questions about Avandia's safety and has campaigned to have it removed from the market. GlaxoSmithKline, which makes Avandia, disputed conclusions that the drug was unsafe, countering that many other studies have found it safe and effective.

"Together they show that this medicine does not increase the overall risk of heart attack, stroke or death," Murray Stewart, the company's vice president for clinical development, said in a statement.

Avandia, approved in 1999 to treat the most common form of diabetes, was once one of the world's most popular drugs. It controls blood sugar levels by sensitizing the body to insulin. But a series of studies has raised questions about whether it increases the risk for cardiovascular problems, a leading cause of death among diabetics. That prompted the FDA to issue a warning about the drug's safety, causing sales to plummet.

Deep divisions among FDA officials about Avandia led the agency in 2007 to decide to leave the drug on the market, and hundreds of thousands of diabetics still use it.