U.S. drugmaker Allergan has rejected the $47 billion takeover bid of Canada-based Valeant Pharmaceuticals International, saying the suitor's proposed cost cuts of at least $2.7 billion annually were too steep.

Allergan, which makes popular anti-wrinkle treatment Botox, said it believed Valeant's business model was not sustainable and that the offer was too risky because of this uncertainty about the company's long-term growth.

"Valeant's model of cutting and slashing really doesn't work for more than a very short period of time," said Allergan CEO David Pyott.

Pyott said Valeant's billions of dollars in cost cuts would prevent Allergan from delivering growth that it could produce on its own. The company's management has set a target of a 20-25% increase in earnings per share in 2015, he revealed.

Valeant and activist investor Bill Ackman, who has a stake of almost 10% in Allergan, made an unsolicited cash and stock offer for the company in April.

News agencies said Allergan could be seeking other buyers, such as Dublin-based Shire.

The Irish company meanwhile has announced plans to pay $260 million for San Diego, California-based biopharmaceuticals producer Lumena Pharmaceuticals, which has expertise in rare diseases including liver conditions.

Shire said it will also make milestone payments related to ongoing clinical trials.