Sept 17 (Reuters) - Auxilium Pharmaceuticals Inc adopted a poison pill with a 15 percent trigger, a day after an unsolicited $2.2 billion buyout offer from Endo International Plc .
Poison pills, or shareholder rights plans, are designed to stop hostile takeover attempts by triggering the issuance of new shares, which dilutes the holdings of all investors if any one exceeds a set threshold.
Auxilium said on Wednesday its board will review Endo's proposal, but it would not modify or withdraw its bid for Canadian eye drug maker QLT Inc .
Endo's offer could complicate Auxilium's buyout of QLT, analysts said on Tuesday. (Reporting by Natalie Grover in Bangalore; Editing by Savio D'Souza)