The Botox maker has rejected a $53 billion joint
offer from Ackman and Canadian drugmaker Valeant Pharmaceuticals
Allergan said in April that its board had adopted a one-year
shareholder rights plan to give it more time to consider
Allergan's shareholder rights plan will trigger if a person or
group acquires 10 percent or more of its shares.
The lawsuit filed in Delaware Court of Chancery followed a
request to Allergan from Pershing Square on June 6 seeking
confirmation that Allergan would not use its poison pill to
impede Ackman's request for a special meeting.
A response from Allerganís counsel on Thursday did not provide
that confirmation, Pershing Square said.
Allergan rejected a sweetened offer from Valeant and the
activist investor on Tuesday.
(Reporting by Natalie Grover and Sweta Singh; Editing by Ted
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