MI risk for rosiglitazone disputed
CNRI/Science Photo Library
Gamma scan of a human heart (in inferior sagittal section) post
MI |
An increased risk of myocardial infarction for people with diabetes
taking rosiglitazone has been identified by the authors of a meta-analysis published
online in The New England Journal of Medicine (21
May 2007). But the drug’s manufacturer GlaxoSmithKline — which
experienced a fall in share price of up to eight per cent on the New
York Stock
Exchange on the day of the article’s publication — has
rejected the study’s findings.
The authors of the disputed analysis looked at data from 42 studies and
found that people treated with rosiglitazone were more likely to experience
an MI than those in control groups (odds ratio 1.43, 95 per cent confidence
interval 1.03–1.98; P=0.03). An increase in the likelihood of death
from cardiovascular events was not statistically significant (1.64, CI
0.98–2.74; P=0.06).
The authors concede that the findings are based on publicly available
trial results rather than patient-level source data, which are more complete
but to which there is limited access. “Furthermore,” they
say, “results are based on a relatively small number of events,
resulting in odds ratios that could be affected by small changes in the
classification of events. Nonetheless, our findings are worrisome because
of the high incidence of cardiovascular events in patients with diabetes.”
In a statement, GSK criticised the findings for being based on a meta-analysis. “The
data compiled from these varied studies [are] complex and can be conflicting,” the
manufacturer said. GSK added that in an analysis of patients in a US
managed-care database of more than 33,000 people with diabetes there
was no difference in ischaemic cardiovascular events, including MI, among
patients taking rosiglitazone-containing regimens compared with other
oral anti-diabetic drugs.
The authors of an editorial (ibid) published alongside the meta-analysis
say that the study’s weaknesses, largely related to the quality
of available data, are substantial. “The possibility that the findings
were due to chance cannot be excluded.”
However, they argue that based on the meta-analysis the possibility of
cardiovascular benefit associated with the use of rosiglitazone seems
remote. They claim: “We are not aware of data showing that rosiglitazone
prevents microvascular disease. In view of the potential cardiovascular
risks and in the absence of evidence of other health advantages, except
for laboratory measures of glycaemic control, the rationale for prescribing
rosiglitazone at this time is unclear.”
Statements issued by UK and European regulators, in response to the study,
point out that information related to the potential for increased risk
of MI with rosiglitazone is already contained within product information.
They advise patients not to stop treatment with rosiglitazone and to
discuss the medicine with their doctor at their next routine appointment.
|
The
Pharmaceutical Journal
Acrobat
Reader