Actavis said Monday that it will spend $219 in cash and stock for each share of Allergan.
That tops a bid for Allergan valued at about $53 billion and made last spring by Valeant Pharmaceuticals International Inc. and the hedge fund Pershing Square Capital Management. That offer totaled about $179 in cash and stock.
Allergan resisted the Valeant deal for months, but its board has unanimously approved the Actavis offer.
Last week, merger talks between Allergan Inc and white knight Actavis Plc were focused on narrowing a gap of about $3 billion between what had been offered and what is wanted, Bloomberg reported.
Actavis was willing to pay around $200 per share, or $60 billion, while Allergan wanted more than $210 per share, Bloomberg said.
Allergan was trying to fend off a hostile takeover by Canadian drugmaker Valeant Pharmaceuticals International Inc , which had offered about $54 billion in cash and stock for the company.
Allergan said two weeks before that it was in talks with a second bidder, and sources familiar with the situation said the company was Actavis.
Separately, Allergan onchanged its bylaws on calling a special shareholder meeting. The move came ahead of a special meeting at which shareholders will vote on a proposal by activist investor William Ackman, who wants a rule change allowing the investors who requested the gathering to set the date for it.
Changing the bylaws is just one of the proxy proposals made by Ackman, who also wants to remove board members and compel Allergan into takeover talks.
The amended laws now include a provision that requires Allergan's board to call for a meeting within 90 days of a valid request rather than exercise its discretion, Allergan said.
The company also reduced the amount of information required from someone calling for a special meeting, and eliminated a requirement to disclose who is acting in concert with the shareholder making the proposal.
Ackman and proxy advisory firms pressured Allergan to change these rules, saying they were too onerous.
Allergan (AGN) shares surged over 7 percent in early morning trading.