Amarin Corp. PLC's fish oil-derived drug Vascepa for risk of cardiovascular disease has been approved by the U.S. Food and Drug Administration.

The FDA approved Vascepa for a certain at-risk patient group that is narrower than the group suggested by the company. The label change resulted from an advisory committee's discussion regarding the appropriate label based on Amarin's clinical trial population.

Vascepa is now approved to be used to reduce risk of cardiovascular events in patients with triglyceride levels of 150 milligrams per deciliter or higher, who also have established cardiovascular disease or diabetes plus at least two other cardiovascular risk factors. Triglycerides, a form of fat found in the blood, are a marker for cardiovascular risk. Other risk factors include diabetes and high levels of "bad" cholesterol called LDL-C.

Amarin had sought expanded approval for Vascepa to treat a broader patient population: those with triglyceride levels of 130 milligrams per deciliter or higher and other cardiovascular risk factors. However, the FDA said in preapproval briefing documents that Amarin's clinical trials had not shown sufficient evidence in this lower-risk patient population.

Vascepa, already approved to treat patients with triglyceride levels of 500 milligrams per deciliter or higher, will be used in conjunction with cholesterol-lowering statin drugs.

The FDA said in its Dec. 13 release that despite the approval for Vascepa, the drug's mechanism of action is still not completely understood. Vascepa is the first nonstatin drug approved for cardiovascular risk, Amarin said in its press release.

According to Amarin, Vascepa will be "promptly" launched in the newly approved patient population.

Cardiovascular disease remains the leading cause of death in the U.S. and worldwide. Cardiovascular events include cardiovascular death, heart attack, stroke and blood clots reducing blood flow known as unstable angina.