What happened

Shares of Amarin (NASDAQ:AMRN) jumped by as much as 11.7% in pre-market trading Monday morning. What's driving this sizable move higher ahead of the opening bell?

On Friday, Amarin announced that the Food and Drug Administration had approved Vascepa as an add-on to statin therapy in patients with elevated triglyceride levels who either have established cardiovascular disease or diabetes mellitus with two additional risk factors for cardiovascular disease. 

Wooden blocks that spell out the word "billion" arranged on a wooden table top.

Image Source: Getty Images.

So what

While the FDA didn't exactly grant Vascepa the broadest label expansion possible, the drug's new target market still encompasses tens of millions of patients. This sizable commercial opportunity, in fact, could make  Vascepa one of the best-selling drugs in the world by the middle of the next decade. 

Reflecting this news, Amarin also rolled out its 2020 sales forecast on Friday, guiding for net revenue of between $650 million and $700 million next year. Based on the forecast, Vascepa is on track to achieve blockbuster status (i.e., more than $1 billion in annual sales) as soon as 2021. 

Now what

The burning question now is whether Amarin will choose to promote Vascepa's new label by itself, bring in a big-time partner, or sell itself outright. Based on the information available at the moment, Amarin appears set to take a go-it-alone approach -- at least initially.

As proof, the company has been aggressively hiring new pharma reps over the last few months in anticipation of this landmark event. But that doesn't mean that a partnering deal or a buyout won't ultimately materialize. Put simply, shareholders may want to think twice about taking profits on this promising mid-cap biotech stock right now. Another big leg up could be right around the corner.  

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.