Part of a major trial looking at diabetes and the reduction of cardiovascular disease has been stopped after data revealed that no drugs, including GlaxoSmithKline’s controversial Avandia, were responsible for the higher-than-expected number of deaths reported.

The National Heart, Lung, and Blood Institute of the US National Institutes of Health has halted one treatment arm of the 10,251-patient ACCORD trial 18 months early due to safety concerns after a review of available data, although the study will continue. Specifically, a halt has been called to a study of adults with type 2 diabetes at especially high risk for heart attack and stroke after it was revealed that 257 patients in the intensive treatment group have died, compared with 203 on standard therapy.

The NHLBI said that this is a difference of three per 1,000 participants each year, over an average of almost four years of treatment, but “the death rates in both groups were lower than seen in similar populations in other studies”. It added that patients in this intensive treatment arm will now be put on less-aggressive therapy.

For both the intensive and standard treatment groups, the clinicians could use all major classes of diabetes drugs, including metformin, insulins, sulfonylureas and thiazolidinediones, primarily Avandia (rosiglitazone). William Friedewald, ACCORD steering committee chair, noted that "because of the recent concerns with rosiglitazone, our extensive analysis included a specific review to determine whether there was any link between this particular medication and the increased deaths. We found no link".

This is particularly interesting as these findings would appear to fly in the face of the notorious meta-analysis published last year in the New England Journal of Medicine, which claimed that Avandia increased the risk of heart attacks and strokes by 43%.

GSK responded to the data by saying that they “appear to raise questions about how aggressively blood sugar should be reduced in managing diabetes”. The UK drugs major noted that “the same drugs are used in both groups of patients who are either managed aggressively or to standard blood sugar control, yet the small increase of events is seen in the group who are aggressively managed.”