For people whose cholesterol is resistant to medication or for those who cannot tolerate statins, a new type of therapy may bring some relief. The treatment uses antibodies to help increase the number of LDL receptors in liver cells, so that more of the “bad” cholesterol molecules can be cleared from the bloodstream. The reason that LDL is known as the “bad” form is that it can aggregate in the blood vessels, forming the plaques that restrict blood flow and put one at greater risk for heart attack.
A while ago it was discovered that statin drugs increased the amount of a particular enzyme, PCSK9, which destroys LDL receptors. So researchers developed a monoclonal antibody known as SAR236553/REGN727, which binds to the enzyme PCSK9. This binding essentially allows more LDL receptors to stick around, which helps rid the body of more LDL cholesterol.
More research will be required to learn more about dosing and safety before they hit the market. Still, to get such a strong effect after giving statins is promising.
In this experiment, the research team randomly assigned people who had been treated with Lipitor for six weeks to one of six groups. The study was a phase 2 clinical trial, meaning that the researchers were trying to find the most effective dose and frequency for administering the drug. Therefore, three groups were injected with the new antibody in high, medium, or low doses (50, 100, or 150 mg) every two weeks. Two more groups had higher doses (200 or 300 mg, respectively) four weeks apart. The remaining group was given placebo.
Another study published this week found similar results for the treatment in people with genetic predispositions to having very high cholesterol and those without this family trait. But this study was a phase 1 trial, and was more interested in safety issues than nailing down the dosing and timing of the drug. Side effects were few, and no patients in the study discontinued the treatment because of adverse effects.
Further research will be required to learn more about dosing and safety before they hit the market. Still, to get such a strong effect after giving statins is promising. “Statins are good medicines and getting a 70 percent reduction on top of them is remarkable,” said lead author James McKenney in a news release. "This is a very hopeful step in the treatment of heart disease in this country.”
McKenney is CEO of National Clinical Research Inc. The study was presented at the American College of Cardiology’s annual meeting and published in the Journal of the American College of Cardiology.
