Avandia: Getting the Facts

In the findings of a study that will appear in the June 14 issue of the New England Journal of Medicine, Dr. Steven Nissen and his colleague Kathy Wolski, evaluated 42 studies that compared patients taking Avandia with patients not using the drug. The studies included nearly 28,000 patients, 15,560 of whom were taking Avandia.

The researchers found the risk of a heart attack was increased 43 percent among those taking Avandia. There is also a 64 percent increased risk of dying from cardiovascular causes while taking the drug.

The implications of these discoveries were considered enough of a public health matter to have caused the New England Journal of Medicine to release the findings several weeks before they appeared in print.

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Fox News Health breaks down some of the facts about Avandia and the Journal's study.

What is Avandia?
Avandia is the brand name for an anti-diabetic drug marketed by GlaxoSmithKline. It was approved by the FDA in 1999 and millions of Americans with diabetes take the drug to help control their blood sugar levels.

How does Avandia work?
It contains rosiglitazone, which is part of the class of prescription drugs called called thiazolidinediones (TZDs). It helps the body use the insulin that it already manufactures. Avandia makes it possible for the insulin the body produces to move glucose out of the bloodstream and into the cells where it's needed for energy.

How is Avandia administered?
Avandia is a prescription tablet available in 2 mg, 4 mg and 8 mg strength and comes in packets of 28s. It can be taken once or twice a day.

Why are these findings considered a public health matter?
Currently, 1 million Americans take Avandia for the treatment of Type 2 diabetes. In this form of the disease, the patient exhibits high levels of sugar in the blood because the body does not respond to insulin, a hormone released by the pancreas that helps glucose move into the cells where it can be used for energy.

How significant is Avandia's increased risk of heart attack? The overall risk appears to be small. There were 86 heart attacks and 39 deaths among the 15,560 Avandia patients, compared with 72 heart attacks and 22 deaths among the 12,283 patients not taking Avandia.

Nissen and Wolski concluded from this data that Avandia may be capable of provoking heart attacks or death from cardiovascular causes after relatively short-term exposure in patients who are already susceptible to these conditions.

What is the FDA's response to these findings? The Food and Drug Administration urged diabetics taking Avandia to talk to their doctors about whether they should remain on the treatment. However, the agency didn't issue a call for a sharper warning label on the drug.

Is there a generic equivalent of Avandia?
Currently, Avandia is what's known as a single source brand, meaning there is no generic equivalent. When a brand-name drug patent expires, the Food and Drug Administration (FDA) can approve generic versions of the drug, which must match the brand name in dosage, strength, performance, use, quality, and safety. Avandia's patent protection expires in 2009.

Are there any equivalent brand name drugs available?
Takeda Pharmaceutical Co. manufactures Actos, a similar product that doesn't have a heart risk. It's a tablet with the active ingredient pioglitazone, which is also in the thiazolidinedione class of drugs. There have been reports of hepatitis and elevated liver enzymes among patients who use this drug. It has not been determined whether these conditions are directly related to Actos.

Eli Lilly & Co.'s Byetta is an injectable medication in a class of drugs called incretin mimetics. They are so named because they mimic the effects of naturally occurring hormones in the intestines and can help the body make more of its own insulin. Possible side effects include an allergic reaction involving hives, difficulty breathing, and swelling of the face, lips, tongue, or throat.

Merck & Co.'s Janumet is an oral medicine combining sitagliptin phosphate with metformin hydrochloride. It is designed for patients who need more than one oral medication to help control their blood sugar. Metformin hydrochloride can cause a rare but serious side effect called lactic acidosis, which is a build-up of lactic acid in the blood that can cause death.

What is GlaxoSmithKline's reaction to these findings?
In a May 21st press release (link), the maker of Avandia points to the limited nature of the study as a reason to be skeptical about the findings. The pharmaceutical company added that, in contrast, GSK has initiated the most comprehensive and rigorous program of scientific analysis for any oral anti-diabetic medicine on the market today, with experience in over 52,000 patients. The company has initiated:

— Extensive clinical trials, including long-term clinical trials in diabetic patients

— A prospective, long-term, clinical trial specifically designed to address cardiovascular safety in diabetic patients

— A proactive, integrated clinical trial analysis of the company's own collected data

— Rigorous monitoring of spontaneously reported adverse events

This data shows that Avandia has a cardiovascular safety profile comparable to other oral anti-diabetic medicines. In addition, independent investigators performed a comprehensive analysis of patients in a U.S. managed care database of more than 33,000 people with diabetes, and showed there was no difference in cardiovascular events among patients taking Avandia- containing regimens versus other oral anti-diabetic medicines.