Cephalon stock up 28% on buyout offer

Buyers drove Cephalon’s share price up 28.41 percent today to $75.44 after Valeant Pharmaceuticals, Canada’s largest drugmaker, offered $73 a share ($5.7 billion) to buy the company in a hostile takeover.

Ontario-based Valeant had approached Cephalon privately but said in a Tuesday statement that the company showed an “unwillingness to engage in discussions in a timely manner.”

Cephalon, based in Frazer, Pa., is best known for its $1 billion narcolepsy blockbuster Provigil. The drug accounted for 40 percent of Cephalon’s global sales last year, but faces generic competition next April.

Cephalon has been on its own acquisition tear recently. On Monday, Cephalon agreed to purchase Australia-based ChemGenex Pharmaceuticals for $230 million, a deal that would give it access to a potential treatment for leukemia. Just days earlier, Cephalon agreed to pay $225 million for Malvern, Pa.-based Gemin X and its pipeline of potential cancer treatments.

In December, Cephalon took a 20 percent stake in Mesoblast Ltd., an Australian-based stem cell company.