TZD diabetes drugs to get black box warning

The US Food and Drug Administration says that the manufacturers of thiazolidinediones (TZDs), a class of medicines used in the treatment of type 2 diabetes, have agreed to place black box warnings on their drug labels. This includes GlaxoSmithKline's Avandia (rosiglitazone) and Takeda's Actos (pioglitazone), as well as all fixed-dose combinations of the two agents: Avandaryl (rosiglitazone and glimepiride), Avandamet (rosiglitazone and metformin), and Duetact (pioglitazone and glimepride).

UK drug major GSK and Japanese drugmaker Takeda will add a stronger warning on the risk of heart failure, a condition that occurs when the heart does not adequately pump blood. The information will be included in a boxed warning, which is the agency's strongest form of safety caution. The upgraded warning emphasizes that the drugs may cause or worsen heart failure in certain patients.

The move is a culmination of safety concerns sparked a few months ago when Avandia was linked to risk of heart attack in a meta-analysis published in the May 21 issue of the New England Journal of Medicine (Marketletter May 28). In the pooled assessment of 42 studies, the GSK drug was associated with a 43% increase in the risk of myocardial infarction and a 64% rise in the risk of death from cardiovascular causes. This month, an FDA panel voted to keep Avandia on the market (Marketletter August 6).