IRVINE, Calif. -- Allergan has reached a friendly deal to be acquired by Actavis PLC in a deal valued at US$66 billion -- possibly blocking a hostile takeover by a Canadian company and its U.S. backer.

Shareholders of the California-based maker of Botox will receive about US$219 per share, comprised of a combination of cash and shares of Dublin-based Actavis.

The deal appears to trump a hostile offer by Quebec-based Valeant Pharmaceuticals, although it has indicated a willingness to raise its bid above US$200 per share.

Allergan has been fighting off a takeover by Valeant, which is working with Pershing Square -- a New York-based private equity firm headed by Bill Ackman that is a major shareholder of Allergan.

Allergan says the white knight offer from Actavis has been unanimously supported by the directors of both companies.