What happened

Shares of Amarin (AMRN -3.54%), a pharmaceutical company that markets a fish oil supplement called Vascepa, are under pressure after the company's first-quarter earnings call. Results that missed expectations prompted the market to drag the stock 42.9% lower as of 10:25 a.m. ET on Wednesday.

So what 

Back in 2019, the Food and Drug Administration approved an expanded indication for Vascepa that was expected to produce windfall profits for the company. Unfortunately for Amarin, a federal court ruling opened Vascepa up to competition from generic versions in 2020.

The stock is sliding today because first-quarter earnings results suggest the company's commercialization strategy isn't working. First-quarter revenue fell 34% year over year to $94 million, which was $33 million less than Wall Street was expecting.

The company also missed expectations on the bottom line. The average analyst following Amarin was looking for a loss of $0.02 per share, but the company reported a much wider loss of $0.08 per share.

Investor looking at a stock chart on a cellphone.

Image source: Getty Images.

Now what

Amarin started selling its fish oil supplement in 2013 with limited success. The landmark Reduce-IT trial proved that treatment with Vascepa lowers the risk of cardiovascular events like a heart attack or stroke for patients who have elevated triglyceride levels despite treatment with cholesterol-reducing statins.

Without patent-protected exclusivity in the U.S., Amarin is relying on the E.U., where its fish oil is marketed as Vazkepa. But Sweden is still the only country in the E.U. that has granted Vazkepa a national coverage determination. This is probably why the company still hasn't provided any revenue guidance for 2022.

As long as there's a shroud over its international expansion effort, it's probably best to watch this pharmaceutical stock from a safe distance.