But this new study of diabetes drug doesn't prove it's safe, critics say
TUESDAY, April 1 (HealthDay News) -- The controversial diabetes drug Avandia appears to slow the progression of atherosclerosis in diabetic patients who have undergone cardiac bypass surgery, thus protecting them from new cardiac problems, according to the results of a small study.
Avandia (rosiglitazone) has been associated with increased risk of heart attack and heart failure among patients receiving the drug. In November, the U.S. Food and Drug Administration, while calling the evidence for heart attack inconclusive, agreed to keep the drug on the market, but with a black box warning about the heart attack risk.
In the new study, which included almost 100 patients taking Avandia, the study authors said they found the drug was safe and had no more cardiovascular risks than a placebo.
The VICTORY (Vein Coronary Atherosclerosis and Rosiglitazone After Bypass Surgery) study included 193 patients with type 2 diabetes who had undergone cardiac bypass surgery. They were randomly assigned to receive Avandia or a placebo. The trial was paid for by GlaxoSmithKline, the maker of Avandia.
The researchers found that after one year, patients taking Avandia had better blood sugar control, compared with those on a placebo. In addition, patients taking Avandia showed improved cholesterol levels, fewer signs of inflammation of blood vessels, and lower blood pressure than those patients taking a dummy pill.
Also, there was no significant difference in cardiovascular events between the two groups, the researchers noted.
"The enrollment of high-risk cardiovascular patients with type 2 diabetes in a placebo-controlled trial with rosiglitazone was found to have an acceptable safety profile," the researchers concluded.
The findings were presented Tuesday at the American College of Cardiology annual meeting, in Chicago. The presenter was Dr. Olivier F. Bertrand, assistant professor at Laval University in Quebec City, Canada.
Despite the study findings, one heart expert said the results were insignificant and didn't really show that Avandia was safe.
"How exactly can they establish the safety of rosiglitazone in a short-term study with less than 100 patients receiving the drug?" asked Dr. Steven Nissen, chairman of the department of cardiovascular medicine at the Cleveland Clinic Foundation, who was the first to report the risk of heart attack associated with Avandia. "This was an intravascular ultrasound study, not a morbidity-mortality study."
Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, agreed with Nissen that the study was too small to make any valid claims about the safety of Avandia.
"This study with only 193 patients is too small to draw any conclusions regarding the potential benefits and risk of rosiglitazone in this patient population," he said.
Dr. Paul Aftring, senior director of metabolic research at GlaxoSmithKline, said, "We recognize the limitation of the size of this study, but the safety data were very reassuring. They are consistent with other data in high-risk populations."
The safety data of any trial is never defined by a population of less than 100 patients, Aftring said. "But the longer-term data in longer-term studies in high-risk populations is actually quite reassuring," he added.
Aftring noted that the current labeling of Avandia says that the drug should be used with caution in high-risk populations. "Victory adds to the knowledge base that in well-managed populations, careful use of rosiglitazone is appropriate, and there are no safety issues," he said.
For more on diabetes drugs, visit the U.S. Food and Drug Administration .
SOURCES: Steven Nissen, M.D., chairman, department of cardiovascular medicine, Cleveland Clinic Foundation, Ohio; Gregg C. Fonarow, M.D., professor, cardiology, University of California, Los Angeles; April 2008, presentation, American College of Cardiologys 57th annual meeting, Chicago; April 1, 2008, prepared statement, GlaxoSmithKline
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