A huge clinical trial studying the diabetes medication Avandia is putting patient' lives at risk and should be stopped, says a prominent Canadian scientist and a U.S. advocacy group.
Dr. David Juurlink has teamed up with the group Public Citizen to write to the U.S. Food and Drug Administration to say that an ongoing trial testing Avandia is "exposing thousands of high-risk patients with diabetes to a drug with an unfavorable safety profile and no clinical advantage over its comparator."
Avandia, or rosiglitazone as it's known generically, was once heavily promoted for Type 2 diabetes for its effectiveness in lowering blood-sugar levels in patients. But it has come under intense scrutiny in recent years.
The drug's potential to raise the risk of heart attacks in some patients was brought to light in a 2007 New England Journal of Medicine article. That report found a 43 per cent higher risk of heart attacks among Avandia patients when compared with those taking other diabetes drugs, including Actos.
Then last June, scientists working on a large study called RECORD, concluded that Avandia did increase heart failure risk in some patients, but didn't increase the risk of cardiovascular death compared with standard diabetes drugs.
The pendulum swung again last August when a Canadian study published in the British Medical Journal concluded that Avandia carried a higher risk of heart failure and death than Actos. Dr. Juurlink and other researchers at the Institute for Clinical Evaluative Sciences (ICES) concluded in that study that switching 1 million patients from Avandia to Actos would prevent 3,700 deaths and 8,300 people from going to hospital around the world.
In a letter written Tuesday to U.S. FDA Commissioner Margaret Hamburg, Public Citizen's Health Research Group Director Sidney Wolfe and Juurlink say that continuing to enroll patients in the trial, known as TIDE, puts people with diabetes at risk unnecessarily.
They say that a "wealth of data now suggests" that Avandia carries greater risks than Actos," and has no clinical advantage over Actos.
They also allege that patients are not being adequately informed about the safety differences between the two medicines when deciding whether to participate in the trial.
Juurlink and Public Citizen say that to continue the clinical trial would be unethical.
The trial is being conducted in 137 sites around the world, including 34 in Canada and six in developing countries.
FDA officials have said they are reviewing all the studies on Avandia and will offer their assessment of the drug's risks and benefits at a meeting in July 2010.
Health Canada has also said it continues to review all available safety information for Avandia and will communicate new safety information to Canadians as necessary.
The manufacturer of Avandia, GlaxoSimthKline, has said it stands behind the safety and efficacy of the drug, when used appropriately.
