WASHINGTON, D.C. (TheStreet) -- Amgen's (AMGN) - Get Report investigational cholesterol-lowering compound evolocumab reduces low-density lipoprotein (LDL) cholesterol by 55-66% compared to placebo, according to data from phase III clinical trials presented over the weekend at the annual meeting of the American College of Cardiology (ACC.)

If approved, Amgen's new drug would represent a medical breakthrough because it lowers cholesterol by inhibiting the PCSK9 enzyme, putting it in a different category than conventional statins. Unlike statins, which are pills, the new PCSK9 inhibitors are injected through the skin.

Amgen estimates 5-15% of patients are statin intolerant due to muscle-related side effects. The company's executive medical director, Dr. Scott M. Wasserman, said evolucumab could also be used as a supplement to statins for patients whose LDL cholesterol level remains high.

Barclays equity research estimates the new class of PCSK9 inhibitors could generate $7-8 billion in revenues in 2020 and said first-mover advantage will be critical. A cooperative venture between Regeneron Pharmaceuticals (REGN) - Get Report and Sanofi (SNY) - Get Report is developing a competing PCSK9 inhibitor, also in phase III trials. Amgen executives said they believe the evolocumab data presented at this weekend's cardiology meeting puts their drug furthest along in the race to approval.

In all, Amgen presented results from five studies of evolocumab at the ACC meeting this weekend:

--  The 12-week MENDEL-2 study of 614 patients with LDL levels of 100 mg/dL or higher who were not receiving therapy found a 55-57% reduction in LDL levels from baseline compared with placebo and 38-40% reduction compared to those who received the statin supplement ezetimibe.

-- The 52-week DESCARTES study of 901 high-risk patients found a mean reduction in LDL levels of 57% compared to placebo and a 49% reduction in the highest-risk patients who received 80 mg of atorvastatin and 10 mg of ezetimibe.

-- The 12-week RUTHERFORD-2 trial of 329 patients with the rare heterozygous familial hypercholesterolemia disorder found a 59-66% reduction in LDL levels compared to placebo.

-- The 12-week GAUSS-2 study of 307 statin intolerant patients found a mean reduction of LDL levels of 37-39% compared to ezetimibe, and the 12-week LAPLACE-2 study of 1,896 patients who received evolocumab in combination with different daily doses of statin therapy found a 38-47% reduction from baseline compared to ezetimibe.

Common adverse events experienced in three trials included nasopharyngitis, headache, contusion, back pain and nausea. Nasopharyngitis was among the most prevalent adverse events, and was experienced by 10.5% of evolocumab patients in DESCARTES.

Of concern to FDA, as well as investors, was the potential for neurocognitive adverse events such as amnesia, but there were almost no such events observed in the trials. Amgen's Wasserman confirmed the company tracked neurocognitive adverse events at the request of FDA, but would not speculate what caused the request.

Amgen officials said the results showed that both bimonthly (140 mg evolocumab every two weeks) and monthly dosing strategies (420 mg every monthly) were effective because the reduction in LDL levels remained largely stable in the interim period between subcutaneous injections.

Amgen's hopes evolocumab's different dosing options will differentiate it from the competions, which in addition to the Regeneron/Sanofi drug includes a Pfizer compound further behind in clinical development.

Wasserman said Amgen intends to begin global regulatory fillings this year, and noted that approval dates would vary by country. Barclays expects Amgen and Sanofi/Regeneron to file with FDA in mid-2015 with a goal of approval in mid-2016.

--Written by Varun Saxena in Washington, D.C.