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What: Relypsa (RLYP), a biopharmaceutical company developing gastrointestinal medicines, saw its shares surge 58% higher at the opening bell today on the news that the Swiss-based Galenica Group bought the drugmaker in an all-cash deal for $32 per share, or about $1.53 billion. 

So what: Once this deal closes in the third quarter of this year, Galenica will gain access to Relypsa's FDA-approved treatment for hyperkalemia known as Veltassa (patiromer). Now that AstraZeneca's (AZN 0.46%) competing hyperkalemia therapy, ZS-9, has been rejected by the agency for manufacturing problems, Veltassa appears to be in prime position to take control of this nearly $6 billion market moving forward..

Perhaps the bigger issue is that some analysts initially pegged Veltassa's peak sales at a mere $200 million due to the presumed near-term entrance of Astra's rival drug. But with ZS-9 out of the picture for the time being, the Street now thinks Veltassa should have enough time as the go-to treatment to achieve blockbuster status.

Now what: Galenica plans to use the acquisition of Relypsa as a springboard to break the company up into two separate companies in 2017. Specifically, Relypsa will be rolled into Galenica's business unit Vifor Pharma, which is expected to be spun off into a publicly listed specialty pharmaceutical company focused on nephrology, cardiology, and gastroenterology medicines. So investors will presumably have yet another chance to invest in Relypsa's novel hyperkalemia drug by purchasing shares of the forthcoming spin-off next year. Stay tuned.