Valeant is raising its offer for Salix Pharmaceuticals to about $11.11 billion, heating up a bidding fight for the company.

The Canadian drug maker's new bid is for $173 per Salix share, a 2 percent premium over Friday closing price of $169.40.

The companies put the deal's enterprise value at about $15.8 billion.

The new bid comes after an offer last week from specialty drugmaker Endo International PLC, which said it would pay 11 percent more for the company than Valeant Pharmaceuticals.

Valeant's prior offer was about $10 billion, or $158 per share. With debt, that deal was valued at $14.5 billion.

Shares of from Valeant Pharmaceuticals International Inc. and Salix Pharmaceuticals Ltd., which is based in Raleigh, North Carolina, are up in premarket trading Monday.