Recent Studies Of Vytorin, Avandia Prompt Debate About FDA Approval Process For New Medications

Recent studies that raised questions about the benefits of the cholesterol medication Vytorin, manufactured by Merck and Schering-Plough, and the safety of the type 2 diabetes treatment Avandia, manufactured by GlaxoSmithKline, are "reigniting debate" about the FDA approval process for new medications, the Wall Street Journal reports. House Energy and Commerce Committee members John Dingell (D-Mich.) and Bart Stupak (D-Mich.) on Thursday sent letters to the American Heart Association, the American College of Cardiology, Merck and Schering-Plough to request information about Vytorin, and Sen. Chuck Grassley (R-Iowa) on Thursday began a separate investigation into the medication.

According to the Journal, the "lawmakers' interest is the latest sign that the flap over" Vytorin, as well as the safety concerns about Avandia, "is adding new fuel to a long-running debate" about the use of "surrogate markers" in the FDA approval process. FDA approved Vytorin and Avandia in large part based on evidence that they helped control cholesterol and blood sugar levels, respectively, with those measures "believed to reflect important clinical benefits" that "serve as proxy markers, or surrogates, for the drug's broader and more important effect on the body," the Journal reports. The use of surrogate markers helps reduce approval times for new medications because "studies can generally be shorter, smaller and cheaper," but the markers "can be misleading," according to the Journal.

Grassley said that, "in light of what's happened with Avandia and Vytorin, maybe the FDA needs to re-examine when it's appropriate to use surrogate endpoints." He added, "These two cases also highlight the importance of vigilant postmarketing surveillance and the need for more postmarketing studies to address important safety questions." Stupak said that "people taking Vytorin are doing so because they believe it will reduce their risk of heart attack." In addition, he said, "It would make sense for FDA to require manufacturers to conduct an endpoint study to determine whether Vytorin just reduces cholesterol or if it also reduces heart attacks."

FDA officials said that they would examine the use of surrogate markers in the agency approval process. A "shift by the FDA toward tougher scrutiny of new drugs could add hundreds of millions of dollars to the cost of developing a drug at a time when some big drug makers are struggling to replenish product pipelines," the Journal reports (Wilde Mathews/Winslow, Wall Street Journal, 1/25).