More On Torcetrapib

The world headquarters of Pfizer Inc. is seen in New York in this April 12, 2005 file photo. Pfizer has cut off all clinical trials and development for a cholesterol drug that was supposed to be the star of its pipeline because of an unexpected number of deaths and cardiovascular problems in patients who used it, the company said Saturday, Dec. 2, 2006. (AP Photo/Mark Lennihan)
AP Photo

Pfizer, the world's largest drug maker, told more than 100 trial investigators to stop giving patients the drug, called torcetrapib. The drug was intended to treat heart disease, but it actually caused an increase in deaths and heart problems.

What is torcetrapib?

The drug, which has been in development since the early 1990s, raises so-called good cholesterol, and cardiologists had hoped it would reduce the buildup of plaques in blood vessels that can cause heart attacks. Good cholesterol reduces the risk of heart disease; bad cholesterol raises it.

Why was the trial stopped?

The world's largest drugmaker said it was told Saturday that an independent board monitoring a study for torcetrapib, a drug that raises levels of HDL, or what's commonly known as good cholesterol, recommended that the work end because of "an imbalance of mortality and cardiovascular events." The drug actually caused an increase in deaths and heart problems. Eighty-two people had died so far in a clinical trial, versus 51 people in the same trial who had not taken it.

What are some of the study's fndings?

Not only were there 31 more deaths among the people taking torcetrapib, but similar discrepancies were seen in the number of patients suffering heart failure and other problems, giving the company no choice but to stop development.

What's the difference between good and bad cholesterol?

LDL particles — clusters of cholesterol molecules surrounded by proteins — act like big boats, transporting cholesterol from the liver and depositing it in blood vessels, where it can cause deadly clogs. In contrast, HDL particles (good cholesterol) pick up cholesterol in the blood vessels and shuttle it back to the liver for excretion.

How many people suffer from heart disease?

Medicines to lower blood pressure and bad cholesterol are already effective and widely used, yet heart disease remains the biggest cause of death in the United States, killing 911,000 people in 2003, according to the American Heart Association.

Does the affect other CETP inhibitors?

Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic, said it is too soon to say whether the entire class of drugs known as CETP inhibitors is dangerous or if there was something specific to torcetrapib that caused the deaths.

To learn more about heart disease:

• Read more about torcetrapib on the Food and Drug Administration.

• Read more about the trial from Pfizer.

• Click here to read more from the American Heart Association.