Contrary to previous findings a new analysis has found no difference between GlaxoSmithKline’s embattled diabetes drug Avandia and Takeda’s Actos in terms of heart risks.

Both drugs belong to the thiazolidinedione class of diabetes drugs, but sales of Avandia (rosiglitazone) have plummeted (more than $5 billion) since research in 2007 suggested it is associated with a significantly higher cardiovascular risk than its rival, metformin and older products.

But now, in direct contrast to prior findings, fresh analysis published in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes, has not found any significant difference between the cardiovascular risk of Avandia and that of Actos (pioglitazone).

The study included 36,628 patients, with an average age of 54, who had submitted insurance claims to health insurance group WellPoint affiliates for either of the two diabetes medications between 2001 and 2005.

Of 28,938 patients who were propensity-score matched (to make results as unbiased as possible), 602 patients taking Avandia and 599 taking Actos over a 33-month period suffered either a heart attack, heart failure, both, or died, equating to around 4% of all patients taking either medication.

On an individual basis, the respective number of patients taking Avandia and Actos who suffered a heart attack was 96 and 121, while 265 and 243 had heart failure. The death was the same for each drug at 217.

Commenting on the results, lead author Debra Wertz said: “Besides its findings that rosiglitazone and pioglitazone have comparable risks, what distinguishes this latest study from other claims-based analyses is its analysis of death records, which include out-of-hospital deaths”. 

In addition, investigators noted that the study also followed patients “for a longer period of time than some of the earlier research”, which could also help account for the different findings.

Authorisation backed 

Stronger warnings of cardiovascular risks have been slapped on Avandia on both sides of the Atlantic since 2007, and the FDA is currently undertaking a second review of the drug’s safety, although it is looking like it will be allowed to stay on the market.

In July, GSK breathed a sigh of relief after 20 out of 33 advisory committee members for the Food and Drug Administration backed the drug’s continued marketing authorisation, although ten of these did vote for additional warnings and restrictions on use, and seven recommended additional warnings only.