FRIDAY, July 9 (HealthDay News) -- One step ahead of a planned government review of the safety of Avandia, new doubts surfaced Friday on a key trial that helped keep the blockbuster diabetes drug on the market.

A medical reviewer for the U.S. Food and Drug Administration posted remarks on the agency's Web site Friday suggesting that drugmaker GlaxoSmithKline's "mishandling" of trial results may have masked some cardiovascular effects of Avandia (rosiglitazone).

The official's posting was part of a safety reassessment package prepared for next week's advisory panel meeting that could determine the future of the controversial drug.

At issue in the review posting were the results of the landmark RECORD (Rosiglitazone Evaluated for Cardiac Outcomes and Regulation of Glycemia in Diabetes) trial, which was done by Glaxo at the FDA's request. The results, announced in June of 2009, found that Avandia raised the risk of heart failure but not to a level of statistical significance. The study also concluded that the drug did not increase the risk of cardiovascular disease or overall death.

In his posting, Thomas A. Marciniak, medical team leader of the division of cardiovascular and renal products at the FDA's Center for Drug Control and Evaluation, said that "RECORD was inadequately designed and conducted to provide any reassurance about the [cardiovascular] safety of rosiglitazone" and that "RECORD suggests the (sic) rosiglitazone increases the risk for [heart attacks]."

Last June, Glaxo used the trial results to tout the drug's safety.

"RECORD provides important and reassuring information about Avandia for physicians fighting diabetes," said Dr. Ellen Strahlman, Glaxo's chief medical officer, in a statement released at the time. "We believe that the results showed that Avandia is safe."

On Friday, the company, in a prepared statement, said, "The RECORD study was conducted according to good clinical practices and the data are reliable. . . RECORD demonstrated that Avandia was not associated with an overall increase in cardiovascular hospitalization or cardiovascular death compared to metformin and sulfonylureas."

But Dr. Kirk Garratt, clinical director of interventional cardiovascular research at Lenox Hill Hospital in New York City, said Friday, "If the data from RECORD had truly been mishandled in some way, not only is it going to pretty well be the end of Avandia in the clinical world, but it's going to put GlaxoSmithKline under the magnifying glass in an important way for clinicians going forward. They'll lose credibility, and that's tough to get back."

"There is an alternative drug out there," Garratt added. "From the clinical side, it's a fortunate circumstance that we find ourselves in, since we have an alternative product that seems to have [little] risk associated with it."

Actos (pioglitazone), made by Takeda, is in the same pharmaceutical class as Avandia. Both are medications known as thiazolidinediones (TZDs), which are blood-sugar-lowering drugs. Both are used by type 2 diabetics.

"The bulk of studies have suggested that Avandia is associated with greater cardiovascular mortality than the alternative, which is pioglitazone," noted Dr. Ronald Goldberg, a professor of medicine at the University of Miami Miller School of Medicine, on Friday.

This is only the latest in a series of conflicting information about Avandia's heart risks. In November of 2007, the FDA added a boxed warning to the drug, saying that there was a potential risk of increased cardiovascular ischemic events. Patients also began receiving a medication guide explaining the risks.

But just last week, three studies emerged with conflicting conclusions about the drug's safety. Two of them, published in major medical journals, found that Avandia did raise heart risks, while the third, released at the American Diabetes Association meeting, found no such connection.

Next week's meeting will shed much-needed light on the matter.

When the advisory panel meets Tuesday and Wednesday, its options "range from allowing the continued marketing of Avandia and revising the label to remove the boxed warning, all the way to withdrawal from the U.S. market," Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research, explained at a packed news briefing late Thursday. "We're asking them to pick one, vote on it and explain the rationale."

But, according to the The New York Times, the panel will also be asked to decide whether a currrent Glaxo study comparing the safety of Avandia and Actos is ethical. The study is being done at the FDA's request.

The FDA is not bound to follow the recommendations of its advisory committees but usually does.

Much of the current controversy, Garratt said, "probably reflects dissent within FDA. They've been debating this internally for a long time. This is probably just turning up the heat on that argument."

Dr. Joshua Sharfstein, principal deputy commissioner of the FDA, told reporters on Thursday, "Obviously, we're going to have to look at a lot of information and really understand the advice that we're getting and try to make a decision as quickly as we can under the circumstances. This is an FDA decision."

Meanwhile, the European Medicines Agency announced Friday morning that it would also review Avandia's safety for use in Europe. The Associated Press reports that the review will be conducted by the agency's Committee for Medicinal Products for Human Use from July 19 to July 22.

More information

The U.S. National Library of Medicine has more on Avandia and Actos.