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Diabetes mellitus: safety information on Avandia

The FDA ( Food and Drug Administration ) is aware of a potential safety issue related to Rosiglitazone ( Avandia ). Safety data from a pooled analysis of controlled clinical trials have shown a significant increase in the risk of myocardial infarction and heart-related deaths in patients taking Rosiglitazone.
However, other published and unpublished data from long-term clinical trials of Rosiglitazone provide contradictory evidence about the risk of ischemic cardiovascular events in patients taking Rosiglitazone.

FDA’s review of all available data is ongoing.

FDA has not confirmed the clinical significance of the reported increased risk of ischemic cardiovascular events in the context of other studies.

Myocardial ischemic events are currently described in the Warnings section of the Rosiglitazone label.

FDA has received additional safety information, a pooled analysis of 42 clinical studies for the treatment of type 2 diabetes mellitus, from the manufacturer of Rosiglitazone, GlaxoSmithKline. There are three products, all manufactured by GlaxoSmithKline, that contain Rosiglitazone: Avandia, Avanadamet ( Rosiglitazone with Metformin ), and Avandaryl ( Rosiglitazone with Glimepiride ). The data from these 42 studies and the associated analyses are complex and are currently being reviewed by the FDA. In the meantime, FDA is providing information on the initial results of these analyses. The degree of risk of Rosiglitazone related to ischemic cardiovascular events is not yet certain.

Recommendations and Considerations

The current prescribing information for Rosiglitazone includes data in the Warnings section about cardiac adverse events ( congestive heart failure and ischemic events ).
Healthcare professionals should consider this and other available data when making individual treatment decisions for their patients with type 2 diabetes.

Background Information and Data

FDA has received data from several different clinical studies of Rosiglitazone for treatment of type 2 diabetes. These studies vary with respect to the study design ( e.g., pooled analysis, individual randomized controlled clinical trial, observational epidemiological study ), patient populations enrolled, treatment groups, and length of patient follow-up. The studies analyzed to date have shown different rates of ischemic cardiovascular events. Based on these data, the risk of ischemic cardiovascular events remains unclear.

Following are summaries of the studies and data.

Clinical Trial Data - Pooled Analysis of 42 Studies

FDA has received the pooled data from 42 separate double-blinded, randomized controlled clinical trials to assess the efficacy of Rosiglitazone for treatment of type 2 diabetes compared to a variety of alternative therapies. The combined studies included 8,604 patients on Rosiglitazone and 5,633 patients randomized to a variety of alternative therapeutic regimens, including placebo.
In general, these studies had differing primary efficacy endpoints; they were not designed to thoroughly investigate cardiovascular safety.
Treatment groups varied and included Rosiglitazone alone or in combination with Insulin, sulfonylureas, and/or Metformin. The comparator arms were varied and included placebo alone or as an add-on treatment to other anti-diabetic agents, and other active anti-diabetic treatment regimens.
The combined patient population was diverse, including patients with average duration of diabetes ranging from 5 to 13 years as well as patients with significant risk factors for cardiovascular disease ( e.g., history of myocardial infarction, bypass surgery, stroke, peripheral vascular disease, and NYHA Class 1 and 2 heart failure ).
All but four studies were of six months in duration.
In this pooled analysis as submitted by GlaxoSmithKline, the overall incidence of myocardial ischemia in Rosiglitazone-treated subjects relative to the comparators was 1.99% vs. 1.51% with a hazard ratio of 1.31. This risk equates to a more than 30% excess risk of myocardial ischemic events in Rosiglitazone-treated patients.

Balanced Cohort Study of Coronary Heart Disease Outcomes in Patients Receiving Anti-diabetic Agents

The Balanced Cohort Study is an observational study of 33,363 patients using a managed care database. Propensity matching was used to match risk factors for cardiovascular disease and other considerations for patients initiating therapy. About 90% of the patients had no history of cardiovascular disease.
The composite cardiovascular endpoint was hospitalizations for myocardial infarction and coronary revascularization.
Patients included in this study began treatment with Rosiglitazone between 2000 and 2004.
The treatment groups were monotherapy with Rosiglitazone, Metformin, or sulfonylurea; oral dual therapy combinations, and Insulin combinations.
Follow-up was 1.2 years.
The incidence of the composite cardiovascular endpoint was 1.75 events per 100 patient-years for the Rosiglitazone-containing regimens and 1.76 events per 100 patient-years for other treatments ( hazard ratio 0.93 ).

A Diabetes Outcomes Progression Trial ( ADOPT )

ADOPT is a randomized, double-blind study of 4,351 patients that compared Rosiglitazone, Metformin, or Glyburide monotherapy on the improvement of and maintenance of glycemic control in patients newly diagnosed with type 2 diabetes.
Patients with underlying cardiovascular disease were excluded.
Median follow-up was 4 years.
The myocardial ischemic event hazard ratios for Rosiglitazone versus Metformin; Rosiglitazone versus Glyburide; and Metformin versus Glyburide were 0.96, 1.16 and 1.22, respectively.
These data do not support an ischemic risk of Rosiglitazone relative to Metformin ( the first line therapy for type 2 diabetes and a drug that has been shown to lower long term cardiovascular risk ).

The Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication ( DREAM ) Study

The DREAM study is a placebo-controlled, randomized, double-blind clinical trial in pre-diabetic patients designed to determine if the use of early treatment with medication could forestall the development of overt type 2 diabetes.
The study was conducted in nearly 5,300 patients who were randomized to either Rosiglitazone or placebo and were followed-up for a mean duration of 3 years.
The study also was intended to examine whether Rosiglitazone and/or Ramipril delayed onset of overt type 2 diabetes.
This study showed an effect of Rosiglitazone in delaying the development of type 2 diabetes ( not found with Ramipril ) in these prediabetic patients.
GlaxoSmithKline has shared with FDA an analysis of the data for Rosiglitazone alone versus placebo which showed no increased risk of myocardial infarction, stroke or cardiovascular death with Rosiglitazone.
FDA has not received the DREAM study data so cannot independently evaluate these data at this time. However, GlaxoSmithKline recently received the data from McMaster University and will be submitting it soon to FDA for review.

Source: FDA, 2007