1．The failure of a high-profile cholesterol drug has thrown a spotlight on the complicated machinery that regulates cholesterol levels．But many researchers remain confident that drugs to boost levels of 'good' cholesterol are still one of the most promising means to combat spiralling heart disease.
　　2．Drug company Pfizer announced on 2 December that it was cancelling all clinical trials of torcetrapib，a drug designed to raise heart-protective high-density lipoproteins (HDLs)．In a trial of 15000 patients，a safety board found that more people died or suffered cardiovascular problems after taking the drug plus a cholesterol-lowering statin than those in a control group who took the statin alone.
　　3．The news came as a kick in the teeth to many cardiologists because earlier tests in animals and people suggested it would lower rates of cardiovascular disease．"There have been no red flags to my knowledge," says John Chapman，a specialist in lipoproteins and atherosclerosis at the National Institute for Health and Medical Research (INSERM) in Paris who has also studied torcetrapib．"This cancellation came as a complete shock."
　　4．Torcetrapib is one of the most advanced of a new breed of drugs designed to raise levels of HDLs，which ferry cholesterol out of artery-clogging plaques to the liver for removal from the body．Specifically，torcetrapib blocks a protein called cholesterol ester transfer protein (CETP)，which normally transfers the cholesterol from high-density lipoproteins to low density，plaque-promoting ones．Statins，in contrast，mainly work by lowering the 'bad' low-density lipoproteins.