Galenica to buy biotech firm Relypsa for $1.5 bln, ahead of split

* Deal brings worldwide rights to potassium medicine

* Builds up Vifor Pharma unit ahead of 2017 split

* Galenica (LSE: 0QKM.L - news) shares down 7 percent (Adds analyst reaction, latest shares, advisers)

By Sylwia Lasek and Ben Hirschler

July 21 (Reuters) - Galenica has agreed to buy Relypsa (Xetra: 0RY.DE - news) for $1.53 billion, paying a big premium for the Californian biotech company to strengthen its Vifor Pharma unit ahead of splitting up the Swiss healthcare group.

Galenica, which owns Switzerland's largest pharmacy network and the Vifor specialty pharmaceuticals business, said on Thursday that Relypsa's board had recommended acceptance of its $32 per share cash offer.

The offer represents a 59 percent premium to Wednesday's closing share price for Relypsa, which makes Veltassa, the first new medicine in 50 years for treating hyperkalemia, or excessive levels of potassium in the blood.

Veltassa could soon face competition from AstraZeneca (NYSE: AZN - news) 's ZS-9, which is currently awaiting U.S (Other OTC: UBGXF - news) . approval, following a delay.

Galenica's Vifor unit already has rights to Relypsa's drug outside the United States and Japan, so the deal will mean the company now has worldwide control of the product. It also boosts its commercial network in the key U.S. marketplace.

However, while the deal bolsters Vifor's profile as a stand-alone business, it leaves little room for it to diversify further and analysts at Jefferies said they were surprised by the move, especially as Veltassa's U.S. launch has been sluggish.

Shares (Berlin: DI6.BE - news) in Galenica were down 7.5 percent at 1264 Swiss francs by 0825 GMT on Thursday.

The transaction comes amid a wave of deal-making in the drugs sector in recent years as larger companies go shopping for promising new medicines from biotech firms to help drive future sales.

The acquisition will be financed with Galenica's own funds and a bridge loan, expected to be partially refinanced through equity proceeds from the group's division, planned for 2017.

Following the closing of the transaction, which is expected during the third quarter of 2016, Relypsa will be delisted and integrated into Vifor. Vifor intends to retain the Relypsa (Xetra: 22479307.DE - news) leadership team in order to support the integration process.

In December Galenica announced plans to separate its Vifor Pharma and Galenica Sante business units into independently listed companies. The company initially expected to complete the division in the fourth quarter of 2016 but had to delay its plans to 2017 due the appointment of Vifor Pharma's new CEO.

Galenica has also raised the like-for-like forecast for the full year for Vifor Pharma due to "excellent momentum", and now expects the unit to achieve an increase of about 10 percent in 2016 earnings before interest and taxes (EBIT).

It said the anticipated investment related to the acquisition of Relypsa might lead to a decrease of 80 million Swiss francs ($81 million) in the company's combined EBIT in 2016 but expects the newly purchased business to generate positive EBIT from 2019 onwards.

Credit Suisse (LSE: 0QP5.L - news) acted as financial adviser to Galenica, while Centerview and BofA Merrill Lynch worked for Relypsa. ($1 = 0.9876 Swiss francs) (Reporting by Sylwia Lasek and Ben Hirschler; Editing by Ryan Woo, Greg Mahlich)