July 22, 2010
Avandia Study Put On Hold By FDA
Federal health authorities are prohibiting new patients from enrolling in a safety study for GlaxoSmithKline's controversial diabetes pill Avandia, a week after an expert panel ruled that the drug increases heart risks.
The Associated Press (AP) reported Wednesday that the Food and Drug Administration (FDA) said it issued a "partial clinical hold" on the study to update researchers on the latest concerns about the drug, which has been under a close eye since 2007.Although the panel of experts voted that the drug appears to increase heart risks, most voted to leave it on the market because evidence was not definitive. The FDA is reviewing the panel's opinions and deciding on what action it should take.
GlaxoSmithKline said in a statement it would halt recruitment for the so-called TIDE trial and update the study's chief investigators on the outcome of the meeting. Patients already in the study will be allowed to continue their participation.
After safety concerns were first voiced in 2007, the London-based drug maker agreed to conduct the trial.
The study is designed to give a definitive assessment of whether Avandia's heart risks are greater than its competitor Actos.
The expert panel voted 20-10 that the trial should continue if Avandia remains on the market. However, critics have argued that the trial is unethical since the current evidence already shows Avandia is riskier than Actos.
Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic told AP that halting enrollment in the trial was the right thing to do.
Nissen first brought attention to Avandia's risks in a 2007 medical journal article estimating that patients taking Avandia were 43 percent more likely to experience heart attack than those taking other diabetes drugs or none at all.
"I still think there's a very good chance that the FDA will decide to remove Avandia from the market," Nissen told AP.
The TIDE study was supposed to enroll 16,000 patients, though concerns surrounding the health risks have slowed recruitments. Researchers reported last week that only 1,100 patients have volunteered for the study.
Dr. Robert Califf of Duke University, a researcher who is leading three major industry-funded diabetes studies, said there is much uncertainty surrounding Avandia's balance of risk and benefit, and not completing the study could leave a huge hole in the information needed by patients and doctors.
He told AP that the FDA's move is "a reasonable and rational step while the company gets its information together," but cautioned that it could push some current study participants to drop out.
The FDA said the researchers should update the informed consent forms used to describe the risks of the study to potential recruits.
Public Citizen's Dr. Sidney Wolfe, who has petitioned the FDA to withdraw Avandia, said the FDA's move is an "important half-step," but said it would not help patients who are already enrolled in TIDE. "It doesn't really speak to the health risks of the people staying in the trial," he told AP. "My guess is most, if not all the people in that study would drop out if they were given information about how much more dangerous Avandia is compared with Actos."
The American Diabetes Association said in a statement that the FDA's announcement only pertains to the TIDE trial and urged doctors "not to over-generalize this announcement to the use of Avandia in clinical care."
The FDA approved Avandia in 1999 and it quickly became the number-one selling diabetes drug in the world. However, US sales plummeted from $2.2 billion in 2006 to $520 million last year due to the rise in safety concerns surrounding the pill.
The FDA added a black box warning to the drug in 2007. New studies on safety combined with pressure from safety advocates has prompted the FDA to take another look at Avandia.
The FDA is expected to make a final decision on whether to keep the drug on the market in the near future.
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