The FDA ( Food and Drug Administration ) announced that the manufacturer of Avandia ( Rosiglitazone ), a drug used to treat type 2 diabetes, has agreed to add new information to the existing boxed warning in the drug's labeling about potential increased risk for myocardial infarctions.

People with type 2 diabetes who have underlying heart disease or who are at high risk of myocardial infarction should talk with their health care provider about the revised warning as they evaluate treatment options. FDA advises health care providers to closely monitor patients who take Avandia for cardiovascular risks.

Avandia, manufactured by GlaxoSmithKline ( GSK ), was approved in 1999 as an adjunct to diet and exercise to improve control of blood sugar levels. Avandia is approved to be used as a single therapy or used in combination with Metformin and sulfonylureas, other oral anti-diabetes treatments.

During the past year, FDA has carefully weighed several complex sources of data, some which show conflicting results, related to the risk of chest pain, myocardial infarction and heart-related deaths, and deaths from any cause in patients treated with Avandia.

At this time, FDA has concluded that there isn't enough evidence to indicate that the risks of myocardial infarctions or death are different between Avandia and some other oral type 2 diabetes treatments. Therefore, FDA has requested that GSK conduct a new long-term study to evaluate the potential cardiovascular risk of Avandia, compared to an active control agent. GSK has agreed to conduct the study and FDA will ensure it is initiated promptly.

The revision of Avandia's existing boxed warning – FDA's strongest form of warning – includes the following statement:

A meta-analysis of 42 clinical studies ( mean duration 6 months; 14,237 total patients ), most of which compared Avandia to placebo, showed Avandia to be associated with an increased risk of myocardial ischemic events such as angina or myocardial infarction. Three other studies ( mean duration 41 months; 14,067 patients ), comparing Avandia to some other approved oral antidiabetic agents or placebo, have not confirmed or excluded this risk. In their entirety, the available data on the risk of myocardial ischemia are inconclusive.

The previous upgraded warning, added to certain diabetes drugs ( in class of drugs related to Avandia ) on Aug. 14, 2007, emphasized that these types of drugs may worsen heart failure, a condition in which the heart does not adequately pump blood, in some patients.
GSK is also developing a Medication Guide for patients to provide additional information about the benefits and risks and safe use of Avandia.

To date, no oral anti-diabetes drug has been conclusively shown to reduce cardiovascular risk. Consequently, the agency also will be requesting that labeling of all approved oral anti-diabetes drugs contain language describing the lack of data showing this benefit.

Action follows recommendations made at the July 2007 joint meeting of FDA's Endocrine and Metabolic Drugs and Drug Safety and Risk Management Advisory Committees.
At the meeting, members voted 22-1 to recommend that Avandia stay on the market, pending a review of additional data.
The Committee also advised that information warning of the potential for increased risk of heart attacks should be added to the drug labeling.

Source: FDA, 2007

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