Questions raised about Avandia tests

Despite government investigations into the safety of diabetes drug Avandia, test subjects are still being recruited for studies into the controverial drug, according to a report.

That has some researchers scratching their heads, since regulators in Canada and the US are grappling with what to do about the drug.

"Exposing thousands of people to this drug for many years, just to see if existing studies are right, doesn't make a lot of sense," says Dr. David Juurlink, the scientist who was the lead investigator in the ICES study that compared Avandia and Actos.

"The idea that you would enroll tens of thousands of patients into a study and give them this drug for years just to see if it is really more dangerous, that to me that is something you might do to guinea pigs, not to patients," he says.

Prof. Jonathan Kimmelman, of the Biomedical Ethics Unit at McGill University in Montreal has reviewed the research so far and says he too is concerned.

"You are randomizing patients to a drug that has an unfavourable risk-benefit balance. That is not right," he said.

Three studies in as many years have raised concerns about the safety of the drug.

Avandia's potential to raise the risk of heart attacks in some patients was brought to light in a 2007 New England Medical Journal article that reported 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. Hertzel Gerstein of McMaster University in Hamilton and lead Canadian investigator of one study, defended the research. "The question we are asking on the trial is overall, are the benefits such that they outweigh the risks of the drug?" he said.