A New Fish Oil for Elevated Triglycerides

The next (April 29th) issue of The Medical Letter includes an article on Vascepa, an omega-3 polyunsaturated fatty acid newly approved by the FDA for treatment of severe hypertriglyceridemia. In our reviews of new drugs, there is always something we don’t know. We often have to say that the answer to a critical question remains to be determined. But the treatment of hypertriglyceridemia presents such a tangled web of ambiguities that the unknowns deserve some extra attention.

First, what is severe hypertriglyceridemia? Some (including the FDA in this instance) say it is a serum concentration of >500 mg/dL. Others say it is >1000 mg/dL. We are concerned about severe hypertriglyceridemia because it poses a risk of pancreatitis, but pancreatitis is very rare at levels <1000 mg/dL and rare even at 2000 mg/dL. So why start treating it at 500 mg/dL? To make sure no one ever gets pancreatitis from high triglyceride levels? Or because there are so many more patients with levels >500 than >1000, let alone 2000?

It gets worse. Do we know that lowering very high triglyceride levels prevents pancreatitis? We do not, and rare, life-threatening diseases like pancreatitis do not lend themselves readily to placebo-controlled trials. There is no compelling reason not to treat very high triglyceride levels, especially with something with as little toxicity as fish oil, but will it help? We don’t know.

If pancreatitis is so rare, why go to so much trouble and expense to bring out a new fish oil to prevent it? Could there be some other, more common, off-label use some people might encourage for Vascepa? We all know the answer to that question. The reason most patients take drugs to lower triglyceride levels is for prevention of coronary artery disease. Do high triglyceride levels cause coronary artery disease? We don’t know. Does lowering triglyceride levels decrease the risk of coronary disease? We don’t know. Does taking fish oil reduce coronary risk? Actually, one large study found that it did, but others found otherwise. So as much as we hate to repeat ourselves, we really don’t know.

Nevertheless, Vascepa is an interesting drug with some promising properties. So read all about it in the next issue of The Medical Letter. And in case you missed it, go back and read our March 4th article on Drugs for Hypertriglyceridemia. There, at last, you will find some answers to your questions. But not all of them.

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Comments

  1. Your honest analysis in this post is impressive and much appreciated, Mark. The dangers of incompletely validated biomarkers.
    Do you think it’s also worthwhile to keep in mind that for some patients, such as those on blood thinners, there could be significant risks to high-dose fish oil, and it should be avoided?

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