AstraZeneca is buying the USA's Ardea Biosciences and its late-stage gout drug for $1.26 billion.

Under the terms of the agreement, the Anglo-Swedish drugmaker is paying  $32 per share, which represents a premium of 54% on Ardea's closing price on April 20. Excluding Ardea's cash, the purchase values the San Diego-based company at $1 billion.

Ardea’s clinically most advanced product candidate is lesinurad (formerly known as RDEA594). It is currently in Phase III for the chronic management of hyperuricaemia in patients with gout. The oral, once-daily treatment  is being evaluated as an add-on treatment to allopurinol and as monotherapy for those patients who are intolerant to allopurinol or Takeda's Uloric (febuxostat) and as an add-on to the latter drug in patients with tophaceous gout.

Filings in the USA and Europe are planned for the first half of 2014 and AstraZeneca also plans to develop and commercialise lesinurad in China and Japan. Through this acquisition, it is also getting hold of RDEA3170, a next-generation selective URAT1 inhibitor currently in Phase I.

Chief executive David Brennan said that "this attractive Phase III programme is an excellent opportunity to leverage AstraZeneca’s global specialty and primary care sales and marketing capabilities". He added that "these compounds have real potential to benefit patients".

Investors do not seem overly impressed about the Ardea buy and at 9.10am this morning (UK time), AstraZeneca shares had dipped 1% to £28.37.