Valeant Chairman and CEO J. Michael Pearson said in a statement that his firm "cannot justify to its own shareholders paying a price of $219 or more per share for Allergan."
"This combination will greatly enhance our U.S. and international commercial opportunities," said Paul Bisaro, executive chairman of Actavis.
The combined company of Activis and Allergan will have an expected $23 billion in revenue and will be led by Brent Saunders, CEO and president of Actavis. Bisaro will remain executive chairman, the company said.
"Today's transaction provides Allergan stockholders with substantial and immediate value, as well as the opportunity to participate in the significant upside potential of the combined company," David E. I. Pyott, chairman and CEO of Allergan, said in a statement.