Avandia, a drug used in the treatment of type 2 diabetes, has been at the center of controversy since being linked to an increased risk of heart attack last May. An update to the black box warning-today’s strongest drug warning-is now being added to the Avandia label. The U.S. Food and Drug Administration (FDA) advised that GlaxoSmithKline, Avandia’s maker, agreed to add the new warning to the existing black box warning. But, despite the revision, the FDA will not withdraw Avandia from the market, claiming that evidence for increased heart attack is inconclusive and does not appear to be higher in Avandia than other type 2 diabetes treatments. In the meantime, the FDA asked GlaxoSmithKline to conduct a long-term study comparing Avandia with other type 2 diabetes drugs. The trial will likely commence in a year; however, full results will not be available until 2014. Patient advocates and FDA critics consider the black box warning a weak response to Avandia’s safety issues and have requested Avandia be pulled from the market.
Avandia breaks down the body’s resistance to insulin but has long been known to cause fluid retention, a major risk factor for congestive heart failure. Evidence does not indicate Avandia and other oral anti-diabetes drugs-thiazolidinediones-prevent cardiovascular risk as a result of reducing blood sugar.
The American Diabetes Association and the European Association for the Study of Diabetes released a revised consensus statement stating that emerging information suggests additional hazards associated with thiazolidedione and rosiglitazone (Avandia) and may result in increased risk of myocardial infarctions. In October, the US Department of Veterans Affairs (VA) announced it was dropping Avandia from its prescription drug formulary stating their review concluded that, in some, Avandia did not afford the same margin of safety as other diabetes medications. The VA accounted for nearly 10-percent of Avandia’s US sales. In November, Health Canada sent a letter to Canadian health professionals advising Avandia could no longer be prescribed as monotherapy for type 2 diabetes or in combination with sulfonylurea. In May, research based on 42 Avandia studies confirmed a 43-percent increased risk of heart attack among patients taking the drug. In August, Avandia’s warning label was changed to warn that Avandia and others in its class might worsen heart failure. A Congressional Committee Report found that company executives made a concerted effort to intimidate a diabetes expert into keeping quiet about Avandia’s safety problems, alleging that Glaxo Chief Executive Jean-Pierre Garnier and former research chief Tachi Yamada were involved. An internal government memo dated July 16, 2002 analyzed 47 early FDA reports of patients who went into heart failure and required hospitalization while taking Avandia. The report contained warnings from Federal investigators that Avandia might cause heart failure.
Over six million Americans have used the drug to treat adult-onset, or type 2, diabetes and the concern about Avandia is nothing new. The association between Avandia and increased heart failure risk has been known since 1999 when the drug was first approved.
Avandia was Glaxo’s second most popular drug in 2006, with sales of $3.3 billion. Sales have plummeted since publication of evidence linking Avandia with increased risk of heart attack and failure.