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FDA Panel Calls for More Testing of Diabetes Drugs

Wants long-term studies to assure medications don't raise cardiovascular risks

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HealthDay Reporter

WEDNESDAY, July 2, 2008 (HealthDay News) -- Drugs designed to control type 2 diabetes should be subjected to more thorough safety reviews to ensure they don't raise the risk of heart problems, U.S. Food and Drug Administration advisers said Wednesday.

The panel of outside experts voted 14-to-2, at the end of a two-day meeting, to recommend that all makers of these drugs conduct long-term cardiovascular trials, even if the drugs show no signs of heart problems in initial trials.

Most of the panel members also said that trials assessing cardiovascular risk should be done before a drug is approved; these could be a part of a phase III trial to rule out any significant heart risk. Long-term trials could follow once the drug was on the market, the advisers said.

Currently, the FDA only requires that drugs for type 2 diabetes lower blood sugar, which is thought to protect diabetics from the debilitating side effects of the disease.

Although the FDA is not required to follow its advisory panels' recommendations, it usually does.

The panel's vote comes less than a year after the FDA was harshly criticized for its handling of the type 2 diabetes drug Avandia (rosiglitazone), made by GlaxoSmithKline. The drug was approved in 1999, but the FDA added a "black box" warning about an increased risk of heart attack last November. And the agency decided to keep Avandia on the market because it concluded that the risk of heart attack wasn't any higher than that associated with similar medications.

Dr. Steven Nissen, chairman of the Cleveland Clinic's department of cardiovascular medicine, first raised concerns about Avandia and heart attack risk in a study published last year. He said in November that he welcomed "the addition of a black box warning for the risk of heart attack from Avandia," but would have preferred a warning "written with greater clarity," like the one used by Health Canada, the FDA's counterpart in Canada.

The Canadian label says Avandia is not to be used as the sole medication for type 2 diabetes except for patients who can't take metformin, another drug that also lowers blood sugar. The label also states that Avandia is not to be used by any patient with heart failure.

The controversy over Avandia started in May 2007, when a study by Nissen and colleague Kathy Wolski, published in the New England Journal of Medicine, found a 43 percent increased risk of heart attack among patients taking the drug. Nissen said he uncovered the risk after poring over data from 42 studies of Avandia.

On Tuesday, Nissen told the FDA advisers that the agency should make companies demonstrate that their type 2 drugs do not increase risks of cardiovascular disease before being approved, the Wall Street Journal reported.

"Merely lowering blood-glucose levels in diabetes is too simplistic," Nissen told the panel. "We must reduce the complications of diabetes, including cardiovascular disease."

Should the agency adopt the panel's recommendation, the additional clinical trials could add years and millions of dollars to the development of any new type 2 diabetes drug. Companies such as Bristol-Myers Squibb and AstraZeneca are currently working on such drugs, the Journal reported.

An estimated 20.4 million Americans have type 2 diabetes, which can lead to kidney failure, blindness and heart disease. About 75 percent of diabetics die from cardiovascular disease.

Sen. Charles Grassley, R-Iowa, is investigating the FDA's approval of Avandia and the cholesterol-lowering drug Vytorin, which did not reduce the build-up of plaque in the arteries.

Recently, the FDA denied approval of another cholesterol-lowering drug from Merck & Co. The denial sparked speculation that the agency has tightened its approval standards for these medications. However, the FDA hasn't said whether changes in its approval process are being considered, the Associated Press reported.

More information

For more on diabetes drugs, visit the FDA.

SOURCES: July 2, 2008, teleconference, U.S. Food and Drug Administration; The Wall Street Journal; Associated Press

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