WASHINGTON -- The U.S. Food and Drug Administration has ordered GlaxoSmithKline, the maker of Avandia (rosiglitazone) to stop enrolling patients in its ongoing head-to-head trial comparing the drug with rival Actos (pioglitazone).
The decision comes after a 19-11 vote last week by the agency's expert advisory panel to keep the trial open. That vote came after the panel voted 20-12 to recommend the FDA allow Avandia to remain an option for patients with type 2 diabetes, despite an increased risk of heart problems associated with the drug. Most panelists want to see the controversial diabetes drug carry tougher warnings on its label.
The FDA required GlaxoSmithKline to conduct the TIDE trial following the agency's advisory committee in 2007 voting to keep Avandia on the market but beef up safety warnings. Practically since the beginning, the trial has been hampered by sluggish enrollment, possibly because of safety concerns.
In briefing documents released in advance of last week's advisory committee meeting, FDA reviewer Dr. David Graham called the trial "unethical and exploitative," as its main purpose is to look for safety issues with Avandia. He also said the informed consent form for the trial obscures the risks of Avandia while focusing too heavily on a more innocuous portion of the study -- a piece designed to detect vitamin D's affect on cancer.
Graham argued that the trial should be shut down.
"Is it ethical to enroll patients in a clinical trial where the goal is to prove harm?" he asked during last week's joint meeting of the Endocrinology and Metabolic Drugs Advisory Committee and the Drug Safety and Risk Management Advisory Committee.
"Going into a trial as a human, you expect to get something good out of it," Graham said. "It's a bad deal trial. The best they can hope for is to not get a drug that causes a problem."
Congressional leaders also have voiced concerns over the TIDE trial. Sen. Max Baucus (D-Mont.) and Sen. Charles Grassley (R-Iowa) -- the chairman and ranking Republican of the Senate Finance Committee -- released a report in February that urged FDA to pull Avandia from the market. Graham, along with another FDA reviewer, contributed heavily to the Finance Committee report.
In addition to the report, Baucus and Grassley wrote a letter to FDA Commissioner Margaret Hamburg questioning the TIDE trial.
"After reading these documents, we would like to know what steps the FDA has taken to protect patients in the TIDE trial, and why this trial is allowed to continue," Baucus and Grassley wrote.
Despite concerns over the trial, the joint advisory committee voted last week keep the trial open, arguing that if Avandia stays on the market, then a head-to-head trial is necessary in order to keep an eye on potential signals that the drug may be unsafe. Several members favored retooling the trial's consent form.
The committee did not vote on whether to halt enrollment.
GlaxoSmithKline has argued at the advisory committee hearing that TIDE is ethical, the trial standards passed dozens of government review boards, and the consent form passed muster with hundreds of ethicists. Still, on Wednesday afternoon, the company confirmed it had halted enrollment in TIDE.