Last week, reports said the pharma giant was in “advanced talks” to buy Acerta for around US$5bn.
Responding to the speculation, Astra said: “There can be no certainty that any transaction will ultimately be entered into, or as to the terms of any transaction.”
Acerta, based in California and the Netherlands, has an encouraging cancer compound that has shown promise in early clinical trials, while Astra is said to be looking to refresh its pipeline of drugs after it rejected a US$120bn bid from Pfizer last year.
Pascal Soriot, chief executive of Astra, said last year that the firm would look at smaller deals, and already agreed to buy California biotech firm ZS Pharma last month for US$2.7bn.
Acerta’s compound is similar to Pharmacyclics’ leukaemia drug Imbruvica and analysts expect it to be a multibillion-dollar seller.
Pharmacyclics was recently bought by AbbVie earlier this year for US$21bn and Imbruvia is expected to become one of the world’s top-selling cancer drugs, exceeding sales of US$5.5bn annually by 2020.
Shares in AstraZeneca lifted 13p to 4,343p.