George Osborne added that it would be “extraordinary” not to engage with US pharmaceutical giant.
Pfizer’s chairman Ian Read says the proposal is a “win-win for society”.
Labour said the firm’s promises regarding the proposed deal were “not worth the paper they are written on”.
Some fear the currently-rejected deal could jeopardise Britain’s science and medical industries.
Meanwhile, the Society of Biology, Biochemical Society, British Pharmacological Society and Royal Society of Chemistry have warned that recent mergers and acquisitions have led to lab closures, threatening the research base.
AstraZeneca has eight sites in the UK and about 6,700 employees.