Two studies and an editorial today should lead the Food and Drug Administration to pull the diabetes pill Avandia off the market, the authors say.
"Taken together, it's going to put a lot of pressure on the FDA to act," says Steven Nissen, the cardiovascular medicine chief at the Cleveland Clinic and co-author of one study, which appears in The Journal of the American Medical Association.
Nissen raised concerns about Avandia's heart attack risk in May with a study in The NewEngland Journal of Medicine. It pooled results of 42 short-term clinical trials and found that Avandia patients were 43% more likely to have a heart attack or be hospitalized for blocked coronary arteries than other patients.
In the latest study, which pooled the results of 19 trials, Nissen and his co-authors found that Actos, the only other marketed drug in the same class as Avandia, reduced the rate of death, heart attacks or stroke by 18%. Nissen says this is the first time a diabetes pill has been shown to reduce the risk of heart attacks, which represent 75% of all diabetes deaths.
Actos maker Takeda provided the trial data and paid $25,000 toward the cost of the analysis. Nissen says he had asked both Takeda and Avandia maker GlaxoSmithKline for clinical trial data about their diabetes pills. Only Takeda obliged, Nissen says, and that was under the condition that it would not see the study before publication.
In the other JAMA study, researchers pooled results from four long-term Avandia trials and concluded that the drug raised heart attack risk 42%. Neither drug in the new studies affected the risk of dying from heart disease, a conclusion that Wake Forest University's Sonal Singh, the lead author on the Avandia analysis, speculated was because the trials were too short.
In a statement Monday, Glaxo argued that these studies, which are meta-analyses, are inherently flawed. Avandia and Actos have never been compared head-to-head, but clinical trials and analyses of large data sets of diabetes patients show no difference in heart attack risk between the two, Glaxo said.
The FDA convened a meeting of outside experts July 30 for advice on the matter. The panelists voted 20-3 that Avandia increases heart risks, but they also voted 22-1 that, overall, it has a favorable risk/benefit profile and should remain on the market.
If a drug garnered such a lopsided vote about its safety before it came on the market, the FDA would probably not approve it, Harvard Medical School doctors Daniel Solomon and Wolfgang Winkelmayer write in an accompanying editorial in JAMA.
"Although removal of a medication creates tremendous patient inconvenience," they write, "the public expects that FDA approval is a seal of safety."
In a statement, the FDA's Susan Cruzan said, "FDA will continue to monitor the safety profile of these drugs and we will provide updates on this issue as they become available."