Nov. 14, 2007— -- The drug Avandia, used by millions of Americans with type 2 diabetes, will now carry a revised "black box" warning saying that there may be an increased risk of heart attack associated with its use, the U.S. Food and Drug Administration announced Wednesday.
But the language of the warning falls short of a conclusive indictment of the drug's increasing heart attack risk. While the additional warning notes that an increased risk of heart attack was seen in one meta-analysis study, it also notes that three other studies "have not confirmed or excluded this risk."
Despite this addition to Avandia's black box -- the FDA's strongest form of warning -- the GlaxoSmithKline drug, will remain on the market as safety assessments of the drug continue, according to an FDA press release. The previous upgraded warning, added to the class of diabetes drugs that includes Avandia Aug. 14, emphasized that these types of drugs could worsen heart failure.
According to the release, the FDA has also requested that GSK conduct a new long-term study to further evaluate the potential heart risks of Avandia.
"FDA has moved expeditiously to review the cardiovascular risks of this drug so that we could inform patients and doctors at the earliest possible time of our findings," said Dr. Janet Woodcock, FDA's deputy commissioner for scientific and medical programs, chief medical officer and acting director of the Center for Drug Evaluation and Research in Wednesday's press release.
GSK stood behind the drug in its own statement issued Wednesday. The company said it would comply with the new FDA requirement but emphasized that research on whether or not Avandia actually leads to an increased risk of heart attack is inconclusive.
"Avandia remains a safe and effective medicine for most patients with type 2 diabetes when used appropriately," said Dr. Ronald Krall, GSK's chief medical officer in the press release. "Given the severity of this disease and the importance of Avandia in helping patients manage their diabetes, we will continue to work with the FDA to conduct more studies about the safety and benefits of our medicine."
Despite the inconclusive nature of the wording of the new warning, physicians seemed content with the addition.
"It seems appropriate, given what we know and don't know," said Dr. Richard Roberts, professor of family medicine at the University of Wisconsin School of Medicine and Public Health in Madison.
"The conclusion of the black box warning is that the data is inconclusive, which I think is fair," said Dr. Anne Peters, director of the University of Southern California's clinical diabetes programs. "Whether or not it should be a black box warning is something that only the FDA can determine."
"I think this is about right," Dr. Mark Molitch, professor of medicine at the Northwestern University Feinberg School of Medicine in Chicago. "I think attention like this should is called for [given] the potential risk, but the drug should not be withdrawn."
The FDA announcement is the latest chapter in the months-long saga over the safety of the drug.
In May, an analysis in the New England Journal of Medicine written by American College of Cardiology president Dr. Steven Nissen revealed that the millions of Americans taking the widely used drug experienced a 43 percent higher risk of heart attacks and a 64 percent increased risk of dying from heart disease.
In an interview with ABC News medical correspondent John McKenzie for "World News," Nissen called the findings "alarming."
"It needs to be confirmed with other analyses, but if the data hold up — and I believe that they will hold up — it does represent a huge public health concern," he said.
In July, an FDA advisory panel agreed that the drug increases the risk of heart attack -- but it voted against recommending that it be pulled from the market.
The findings fueled existing criticism over the FDA's drug approval and regulation procedures.
Since the FDA approved it in 1999, more than 7 million people worldwide have taken Avandia. Currently, about 1 million Americans take the drug, designed to lower the body's sensitivity to insulin.
In total, more than 60 million prescriptions have been written for the drug, and it generates annual sales worth $3 billion annually.