By Jennifer Corbett-Dooren Of DOW JONES NEWSWIRES WASHINGTON (Dow Jones)--A Food and Drug Administration panel said clinical data looking at GlaxoSmithKline PLC's (GSK) diabetes drug Avandia is strong enough to raise "significant safety" concerns about the product. The panel also said Avandia appeared to have more cardiovascular risks compared to a competitor drug, Actos. The panel of non-FDA medical experts is currently voting on a series of questions about Avandia and will vote later Wednesday on whether it thinks the product should remain on the U.S. market. In 2007, a similar FDA panel said Avandia appeared to raise the risk for heart trouble, but overwhelmingly voted to keep Avandia on the market. Specifically, the current FDA panel voted 18 to 6 in favor of a question that asked whether clinical data were sufficient to raise "significant safety" concerns regarding Avandia relative to other diabetes drugs. However, nine members of the same panel said they couldn't make a finding one way or the other, showing the panel struggled to make sense of various clinical studies that were presented during the two-day meeting. However, 21 members of the panel said they thought clinical data showed that Avandia increased "ischemic CV events" relative to Actos, a similar drug made by Takeda Pharmaceutical Co. (TKPYY, 4502.TO). Avandia's safety has been in question since a 2007 article in the New England Journal of Medicine by Cleveland Clinic cardiologist Steven Nissen showed it raised the risk of heart attacks by more than 40%. Nissen's study was an analysis of 42 existing studies, most of which lasted a year or less. GlaxoSmithKline has argued that long-term studies don't show such a risk. Heart failure from excess fluid retention has been a long-recognized problem with Avandia and Actos, and both products already carry the FDA's toughest boxed warning discussing that risk. The issue with Avandia is whether it raises the risk of heart attacks and other cardiovascular problems more than other diabetes treatments. Additional Avandia studies since 2007 have only added to the controversy surrounding the drug. Last year, Glaxo released the results of a company-funded study, known as Record, that didn't show an increased heart-attack risk. The study, which involved about 4,500 patients, compared patients on Avandia with those receiving other diabetes drugs, metformin or sulfonylurea, for an average of 4 1/2 years. It showed a similar rate of hospitalizations and deaths among patients receiving Avandia compared to patients on the other diabetes medications. During Tuesday's portion of the panel meeting, FDA officials questioned the integrity of the Record data and debated whether it affected the study's final conclusions. Avandia was once a multibillion-dollar-a-year medicine and one of Glaxo's top-selling drugs. Since the drug has come under attack, sales have slumped. In the first quarter of this year, worldwide sales of Avandia were about $245 million, down 10% from a year earlier. Both Avandia and Actos were approved in 1999 as a treatment for Type 2 diabetes, the most common form of the disease, and are both designed to lower blood-glucose levels. Diabetes affects about 24 million Americans and is characterized by high blood glucose levels caused by the body's inability to either make or properly use insulin. -By Jennifer Corbett-Dooren, Dow Jones Newswires; 202-862-9294; [email protected] -0- (MORE TO FOLLOW) Dow Jones Newswires July 14, 2010 14:06 ET (18:06 GMT)