Wednesday, June 06, 2007

Interim Analysis of Rosiglitazone and Cardiac Safety "Inconclusive"

An interim analysis of the cardiovascular risks of rosiglitazone (Avandia) shows a significant increase in heart failure and inconclusive results regarding hospitalization or death from cardiovascular causes, according to a study released early by the New England Journal of Medicine.
The analysis of data from an ongoing open-label, manufacturer-sponsored trial was undertaken in response to a meta-analysis published last month. In the trial, researchers randomized some 4450 patients with inadequate control of type 2 diabetes on either metformin or sulfonylurea to receive both those drugs (controls) or add-on rosiglitazone.
Mean follow-up was 3.75 years. When all patients with potential primary endpoints — hospitalization or death from cardiovascular causes — were included, the hazard ratio was 1.11. The confidence interval of the hazard ratio was wide, leaving the possibility of anywhere from a 7% improvement to a 32% worsening of cardiac risk with rosiglitazone.
The study's authors call their interim results "inconclusive."
One editorial says that even when completed, the study's ability "to reach a definite conclusion about cardiovascular safety is uncertain." It argues more generally that "drugs cannot easily be parsed into 'safe' and 'unsafe' categories. Instead, there will be shades of safety that must be graded against shades of efficacy."
Another editorial says that these interim results "do not provide any assurance of the safety of treatment with rosiglitazone."

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