Avandia has come under increased scrutiny since the February release of a report commissioned by the US Senate Finance Committee. The document claimed that Avandia manufacturer GlaxoSmithKline (GSK), based in the UK, had long been aware of the risks associated with its diabetes drug, but chose to withhold that information.
According to yesterday's issue of Global Insight, GSK countered by saying that the report failed to take into account various clinical studies that pointed to the contrary.
Meanwhile, a trial known as the TIDE study is currently underway to compare Avandia (rosiglitazone) with competitor Actos (made by Takeda and known generically as pioglitazone). Dr. Wolfe told the House Agriculture-FDA Appropriations Subcommittee on April 28 that the study should be abandoned, given the risks for heart attack, heart failure, bone fractures, anemia and vision loss associated with Avandia. Dr. Wolfe noted that there is already sufficient evidence of Actos's better safety record, which should be reason enough to deem the TIDE trial unnecessary.
Public Citizen has been railing against Avandia since October 2008, when it originally petitioned the US Food and Drug Administration (FDA) to ban the drug. The TIDE trial, a massive undertaking involving 16,000 individuals in 14 countries, was requested by the FDA.
Since the release of the damming report by the US Senate Finance Committee this past February, the FDA is continuing to scrutinize not only Avandia but also the validity of the TIDE trial. However, until the federal agency makes up its mind, the TIDE trial continues with the recruitment of participants.
In his remarks to the House Agriculture-FDA Appropriations Subcommittee, Dr. Wolfe cited various studies that supported his position.
One Canadian study, published last August, evaluated cardiovascular outcomes in 39,736 people who were started either on rosiglitazone or pioglitazone from 2002 through 2008. "The authors found major differences in the risk of congestive heart failure and death from any cause in patients taking rosiglitazone as compared to those taking pioglitazone," he said. "They estimated that one additional hospitalization for heart failure would occur annually for every 120 patients prescribed rosiglitazone rather than pioglitazone, and that one additional death would occur each year for every 269 patients treated with rosiglitazone rather than pioglitazone (Actos)."
A Johns Hopkins study reviewed 40 randomized, controlled trials involving cardiac risks of older and newer diabetes drugs and found that metformin hydrochloride was the only drug associated with a decreased risk of cardiovascular mortality compared with any other oral diabetes agent or placebo. "The only diabetes drug with increased cardiovascular risk was rosiglitazone (Avandia), for which the increased risk was 1.68, falling just short of statistical significance," Dr. Wolfe said. "Pioglitazone (Actos) had neither increased nor decreased cardiovascular risk in the six randomized trials that comprised the study.
READ MORE AVANDIA LEGAL NEWS
"The TIDE trial can only continue with the misplaced objective of proving definitive proof of what many studies have already suggested—that rosiglitazone is indeed more dangerous than pioglitazone. The price of such definitive proof will almost certainly be measured in the lives of study subjects who have been incompletely informed about the available evidence regarding the risks and benefits of participation."