Trial Cholesterol Drug Strikes Out
Torcetrapib Fails to Slow Plaque Buildup in Arteries
March 27, 2007 (New Orleans) -- Three new studies show that the novel cholesterol drug torcetrapib fails to slow plaque buildup in the arteries.
Torcetrapib was also recently linked to an increased risk of heart attacks and death. Additionally, the new drug may raise blood pressure, the research suggests.
Despite the setbacks, experts say there may still be a role for drugs similar to torcetrapib aimed at preventing heart disease by raising "good" HDL cholesterol.
In December, Pfizer Inc. announced it was stopping clinical trials of torcetrapib because of the increased heart risks associated with its use.
But researchers are continuing to analyze previously accumulated data in hopes of finding out why the drug failed.
Approach Still Promising
“A lot of people think it's the next big thing, so we need to understand what went wrong with torcetrapib to move forward,” says Steven Nissen, MD, head of cardiovascular medicine at The Cleveland Clinic and president of the American College of Cardiology (ACC).
“We believe the failure doesn't necessarily rule out the possibility that another drug in the class, one that is completely clean, with no blood pressure effects and no other evidence of toxicity, could possibly work," he tells WebMD.
Nissen notes that if Baycol had been the first statin tested and research had stopped after safety problems emerged, statins would never have been developed. Baycol, sold by Bayer AG, was withdrawn from the market in 2001 after reports of a severe and sometimes fatal muscle disorder.
“We don’t want to abandon a potentially lifesaving drug, but the bar has been raised. We have to move forward carefully,” he says.
A Strategy of Boosting HDL
Doctors say there is an urgent need for drugs that fight heart disease in novel ways. While credited with making a substantial dent in heart disease, statin drugs that lower "bad" LDL cholesterol don’t help everyone: Some statin users suffer heart attacks anyway.
“You could put statins in the blood supply, and cardiovascular disease would still be the leading cause of death. We need something else,” Nissen says.
That’s why doctors have been trying to boost levels of HDL cholesterol, which ferries cholesterol from the bloodstream to the liver where it can be disposed of.
Torcetrapib works by inhibiting an enzyme responsible for transforming good cholesterol into bad cholesterol. “If you block this enzyme, HDL goes up and LDL goes down,” Nissen says.