Allergan to buy Kythera Biopharmaceuticals for $2.1 billion

Botox-maker Allergan Plc (AGN.N) said it would buy Kythera Biopharmaceuticals Inc (KYTH.O) in a cash-and-stock deal valued at about $2.1 billion, to expand its line of cosmetic treatments.

The offer price of $75 per share represents a premium of 23.5 percent to Kythera's Tuesday close.

Kythera's shares rose 22.7 percent to $74.50 in premarket trade on Wednesday, just shy of Allergan's offer price.

Buying Kythera will give Allergan access to Kybella, the first and only approved non-surgical treatment to reduce fat under the chin, the companies said.

The equity value of the deal is about $1.94 billion, based on 25.8 million Kythera shares outstanding as of April 6, according to Thomson Reuters calculations.

The deal is Allergan's first multi-billion acquisition since it was bought by Actavis Plc for $66 billion. Ireland-based Actavis, which announced the Allergan deal in November, adopted the Botox-maker's name on June 15.