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What happened

Shares of Raptor Pharmaceuticals (NASDAQ: RPTP), a rare-disease drugmaker, gained as much as 20% in pre-market trading today. This hefty surge is the result of a reported $800 million all-cash buyout offer from Horizon Pharma (NASDAQ:HZNP). According to the press release, this deal should close sometime in the fourth quarter of 2016. 

So what

This deal further strengthens Horizon's growing orphan disease franchise, and supports the drugmaker's pivot away from the controversial specialty pharma space. By acquiring Raptor, Horizon will add to its portfolio of orphan drugs the nephropathic cystinosis (a rare metabolic disorder) treatment Procysbi and the cystic fibrosis medication Quinsair. 

Now what

Although this acquisition will reportedly add $675 million in debt to Horizon's already highly levered balance sheet, it is expected to be accretive to the company's adjusted EBITDA in 2017. But perhaps most importantly, this deal shows that Horizon is indeed serious about transforming into an orphan drug company in order to put the headwinds surrounding the specialty pharma drug pricing controversy behind it. That's really good news for shareholders in this politically charged environment.

After all, drugmakers could face some serious pushback from lawmakers and pharmacy benefit managers over drug pricing points once the U.S. presidential election wraps up. And Horizon would almost certainly be a prime target due to products like the arthritis drug Duexis, which has drawn tremendous heat over in the past as a result of its sky-high price tag.

All told, this deal seems like a particularly good fit for Horizon, especially since it should set the company up for sustainable, long-term growth going forward. That's why it might be worth grabbing some shares of this mid-cap growth stock today.

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.