CHICAGO, April 5 (UPI) -- A drug that lowers bad cholesterol and significantly increases good cholesterol, which doctors expected would increase cardiovascular health, failed to reduce rates of adverse health events in a large clinical trial, according to researchers.
Drug maker Eli Lilly halted a trial of evacetrapib in 2015 based on a lack of reduction in heart attack, stroke, the need for surgery or hospitalization, or the amount of time high-risk patients survived to cardiovascular death, researchers said in a presentation at the American College of Cardiology's 65th Annual Scientific Session.
While evacetrapib posed no safety concerns and caused no major side effects, researchers said the trial suggests the benefits of HDL cholesterol, referred to as "good" cholesterol, have been overestimated by doctors and scientists.
The theory may be sound, based on a recent study conducted at the University of Pennsylvania showing the way the body processes cholesterol is as important as levels of good or bad cholesterol in predicting heart attack or other cardiovascular health risks.
Evacetrapib is the third drug in a group called cholesteryl ester transfer protein inhibitors meant to disrupt the process turning HDL cholesterol into LDL, or "bad," cholesterol. Of the other two drugs, dalcetrapib was as ineffective as evacetrapib at preventing cardiovascular events, while torcetrapib increased risk.
"There has been, and continues to be, a lot of confusion about what's going on with this class of drugs, since we don't yet have one that can be brought to the clinic to prevent heart attack and stroke in our patients," Dr. Stephen Nicholls, a professor at the University of Adelaide, said in a press release. "As we close out the trial, we're trying to understand how a drug that seems to do all the right things in terms of blood cholesterol levels doesn't then translate into reducing clinical events."
The phase 3 randomized trial for evacetrapib enrolled 12,000 patients around the world at high risk for cardiovascular events, treating them with 130 milligrams of the drug or a placebo daily for 18 months. All patients already being treated for other conditions, including with statins or other drugs to lower cholesterol, continued with their regular drug regimens.
Overall, patients treated with the drug had 37 percent lower levels of bad cholesterol and 130 percent higher levels of good cholesterol, but researchers report there was no difference in cardiovascular endpoints between the treatment and placebo groups.
"As we gain further evidence with this class of medications, there is further skepticism as to whether or not these drugs are actually going to be effective in the treatment of cardiovascular disease," Dr. Jeffrey Kuvin, a cardiologist at Tuft's University Medical Center and co-chair of the conference, told CBS News.
While the researchers said they were surprised and disappointed by the trial's results, future studies focusing on other groups of patients need to be conducted, perhaps with those at lower risk for cardiovascular events or who are not already being treated with other cholesterol drugs.
"We tested the drug in high-risk patients because they are the patients with the greatest need for new drugs above and beyond what we already use in our clinics," Nicholls said. "Low risk patients could be another group of patients that could potentially benefit from this drug, but we didn't test that and to do so would require an extraordinarily large study that asks a different question from the one our study was designed to address."