Treating high cholesterol can be as easy as taking medication to lower LDL and raise HDL levels.
But it's not that easy for many people. Drs. Ahmed F. Aslam and Stephen Devine prescribe similar drugs for La Crosse area patients to treat high cholesterol, one of the leading risk factors for heart disease, and one patient will end up with improved levels and the other doesn't.
"HDL, the good cholesterol, complicates things," said Devine, a Gundersen Lutheran cardiologist. "We don't know enough about the characteristics of HDL cholesterol. It is a very complex lipid particle that is not well understood."
Aslam, a Mayo Clinic cardiologist at Franciscan Skemp, said HDL, which carries the LDL or "bad" cholesterol away from heart artery walls, has frustrated doctors. "We see patients with no other issues than a striking low HDL range, and we don't know exactly what to do about it," Aslam said.
Losing weight, increasing physical activity and quitting smoking can help lower LDL and raise HDL, but it doesn't work adequately for many patients, Devine said.
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"With drug treatment we're very good at lowering LDL, but not so good with HDL," Devine said. "But there is some hope down the road."
Doctors have long agreed that large LDL levels can cause blockages in arteries, or blood clots, which can trigger a heart attack or stroke. LDL cholesterol can build up in your arteries and prevent the blood from getting to your heart.
But researchers now are finding that greater levels of HDL may be less important than how well your particular HDL removes the bad cholesterol from arteries and carries it back to the liver to ultimately pass out of your body.
Dr. Christopher Cannon, a cardiologist at Brigham and Women's Hospital in Boston, just completed a clinical trial last fall, which found that an experimental drug called anacetrapib upped HDL levels by 138 percent in six months and maintained that rise over
18 months without the negative side effects shown by other medicines in the same class.
The oral medication being developed by Merck also reduced LDL levels by 40 percent among patients also taking a statin drug, the most popular medication class for lowering bad cholesterol.
Anacetrapib will now proceed to a four-year global clinical trial involving 30,000 patients.
"It's our first hint that the good cholesterol story is more complicated, that you can't just increase the level and expect it to work properly," Cannon said.
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Devine said it's possible that a patient with high levels of good cholesterol may not be receiving as much protection as hoped for, but also a person with low levels that are very efficient may be better off than previously thought.
Whether HDL is biologically active and how it works to transport the bad cholesterol and dump it off in the liver is a critical issue in treatment, Devine said.
"The excitement is tremendous here," Devine said. "If we found this drug to be so helpful by itself, then we may have a drug with dramatic benefit dealing with No. 1 killer in this country."
Some other FDA-approved drugs are thought to raise good cholesterol, but niacin is the only one to do so by any significant level (25 percent). A separate study found signs that HDL ability to remove bad cholesterol may be better in patients treated with anacetrapib than those who received niacin or no HDL-promoting medication.
"With HDL we hit a roadblock, Aslam said. "We hope to increase levels with diet, exercise and medications, but we never had a good drug without the side effects."
Anacetrapib doesn't have the side effect profile of other medications, he said.
"Its impact on HDL is staggering and decreases LDL as well, Aslam said. "It is quite amazing.
"This drug may open to the gateway for further investigation to a new class of drugs," he said. "But we're far from saying it will be the gold standard. We need a clinical trial on a larger basis to show it is safe."
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If anacetrapib is found to be effective and safe in future studies, it wouldn't become available on the market for at least three to five years, Aslam said.
Copyright (c) 2011, La Crosse Tribune, Wis./Distributed by McClatchy-Tribune Information Services.
