Though there are a lot of drugs used to lower bad cholesterol, the search for potent ones to increase good cholesterol levels is not easy. Drugmaker Eli Lilly developed evacetrapib to increase good cholesterol in the body, but was not able to prevent cardiovascular events like heart attack and stroke.

Low density lipoprotein (LDL) or bad cholesterol has been linked to major cardiovascular problems because it's the main culprit narrowing the vein's opening, thus, decreasing the flow of blood to vital organs in the body. It's also seen as a major predisposing factor to increased blood pressure.

In a presentation at the American College of Cardiology, researchers reported the latest findings on a study about evacetrapib. The drug, which has shown promise in increasing good cholesterol levels and reducing the bad ones, didn't seem to reduce heart disease events.

Once Promising

The study, which involved 12,000 patients across 540 global health centers, showed that patients taking the drug had lower levels of LDL by 37 percent and had increased HDL levels of 130 percent. This may sound promising, but the favorable effects on cholesterol levels did not translate into reduced risk of stroke and heart attack.

At present, this attempt was the third one in a class of drugs known as cholesteryl ester transfer protein (CETP) inhibitors. These drugs disrupt the natural process by which good cholesterol is transformed into bad cholesterol in the body. The first of the two other drugs that failed in this attempt increased the risk of heart problems and death, while the second one wasn't effective.

What Went Wrong

The study findings stunned the researchers. They have hypotheses, but no one is sure what really went wrong.

"This drug did all the right things to lipids but didn't do anything to morbidity and mortality from heart disease," said Dr. Steven Nissen, chair of cardiovascular medicine at the Cleveland Clinic.

He said it's still unclear how a drug designed to lower LDL and increase HDL does not reduce the risk of heart problems. It is possible that since LDL comes in many forms, with some more potent in inflicting harm to the heart than others, evacetrapib may be boosting the production of the more harmful type.

Moreover, even if the bad cholesterol levels are reduced, there may still be vessel blockages in the heart, leading to an increased risk of a heart attack.

Increasing HDL Is Not Enough To Prevent Cardiovascular Events

It has been widely known that increasing HDL levels may prevent heart attack risk. These good cholesterol molecules help remove bad cholesterol in the blood stream, leading to the prevention of fat deposits inside the blood vessels.

"As we learn more about this class of medications, perhaps it is not enough to raise HDL and lower LDL and see beneficial effects," Dr. Jeffrey Kuvin, a cardiologist at Tuft's Medical Center, said.

The researchers added that since treatments that lower bad cholesterol levels are now effective, it may be harder to further improve outcomes especially in high-risk patients. Evacetrapib's biological pathway or active ingredient may be designed to just affect cholesterol levels, but not reduce the risk of cardiovascular events.

Photo: Ed Uthman | Flickr

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