The September 2007 Journal of the American Medical Association (JAMA) has published two new studies, one a meta-analysis of Avandia (rosiglitazone) and the other a meta-analysis of Actos (pioglitazone).
Although both drugs are thiazolidinediones, which help control glucose by increasing sensitivity to insulin, they work in different ways. And the news is not good for beleaguered Avandia (and not all that rosy for Actos, either).
The Avandia study, which looked at four long-term trials comprising 14,291 people, found that Avandia increased risk of heart attack by 42 percent and doubled risk of heart failure, but did not increase the risk of cardiovascular death. The findings about heart attack risk were essentially the same as those of an earlier JAMA meta-analysis of shorter-term studies, the one that ignited the recent controversy over Avandia’s safety.
The Actos meta-analysis looked at nineteen trials comprising more than 16,000 patients. It found that Actos lowered risk of heart attack, stroke, and death by 18 percent, but raised risk of heart failure by forty percent.
In essence, both drugs increase risk of heart failure, a problem that is highlighted by the FDA black box warnings now required on both drugs. The difference lies in their effect on risk of heart attack, which Avandia raises and Actos apparently lowers, possibly because of their differing effects on cholesterol.
The Actos meta-analysis was funded by Actos’ manufacturer, Takeda. Avandia’s manufacturer, GlaxoSmithKline, pooh-poohed the positive finding about Actos, indicating that it was too heavily based on one flawed Takeda-funded study and that there is no difference in safety between the two drugs.
Sources: CBS News; EurekAlert; Medline Plus