AstraZeneca's board will be reviewing a sweetened takeover offer from Pfizer but the company has no further comment at this stage, a spokeswoman for the British drugmaker said on Friday.
The US drugmaker Pfizer revealed it had raised its offer for the British group to £63 billion pounds.
The deal could create the world's biggest drugs company, as well as the biggest takeover of a UK company in history.
Shares in Astrazeneca have rose to £48.31 in early trading on Friday after Pfizer raised its offer for the British company to £50.00 per share.
Pfizer has until Monday until it admits defeat in bidding for AstraZeneca. But after the shenanigans of the past few days we cannot be sure.
AstraZeneca's share price is tumbling back down to earth after the board rejected a "final" Pfizer bid. So is the takeover really over?
Sweden's Finance Minister says the Government should be "very, very sceptical" about any promises the US pharmaceutical giant makes.