GlaxoSmithKline’s diabetes drug Avandia (rosiglitazone) has failed to show it can significantly reduce atherosclerosis in patients with type 2 diabetes.

While study results, presented at the American Heart Association scientific meeting, demonstrated the endpoint did not reach statistical significance, the drug giant is maintaining it is “encouraged” by the findings suggesting that treatment with Avandia “may stall the progression of coronary atherosclerosis”.

“This study supports but does not prove the hypothesis that rosiglitazone has greater anti-atherosclerotic effect than glipizide in patients with type 2 diabetes,” said lead study investigator Dr Richard Nesto, Reuters reported.

The study is not good news for GSK, as Avandia has failed to produce positive results in a number of clinical trials and has even been linked to an increased risk of heart attack.

The news also follows last month’s decision by the American Diabetes Association and the European Association for the Study of Diabetes, which issued new treatment guidelines to doctors recommending that Avandia not be used. There have also been suggestions that drug causes liver failure.

The study, called APPROACH, compared the reduction of atherosclerotic plaque volume between Avandia and sulfonylurea glipizide, marketed by Pfizer as Glucotrol.

Results from the 18-month 672-patient study found patients who took Avandia achieved a 0.21% reduction in atherosclerotic plaque, while patients taking glipizide achieved a 0.43% increase.

In terms of safety, there were no unexpected differences between Avandia and glipizide, GSK said.

However, Avandia was found to be statistically significantly better that glipizide in measures of total volume of blood vessel blockage and fewer low blood sugar incidents.

Independent scientists have reported that the results should be interpreted with caution.

Avandia sales fell 23% to $314 million in the third quarter. Results from a study assessing the drug’s safety are not expected for another two years.