Dutch-based US pharmaceutical giant Mylan's independent foundation said Thursday it will excercise a call option allowing it buy shares to control half the company in fending off a hostile takeover bid by Israeli rival Teva.

The foundation "formed its independent judgement that Mylan's best interests are at risk as a consequence of the uncertainty and threats associated by a possible takeover by Teva," Mylan said in a statement.

Mylan, a US company that moved to the Netherlands a year ago for fiscal reasons, had dismissed Teva's earlier bid in April.