The stock was up 25.05 percent before being halted for news pending.
Concordia later said in a release it had formed a "special committee to review strategic alternatives." Such special committees are often, but not always, seen as a sign that a company is up for sale.
Bloomberg said, citing people close to the matter, that talks between the two companies were at an early stage, adding that a deal may not happen.
Concordia's stock has fallen nearly 60 percent in the past year, and more than 25 percent in 2016.
CXRX in the last year