LONDON and SAN DIEGO — AstraZeneca plans to buy Ardea Biosciences Inc. in a cash deal valued at $1.26 billion.

The companies said Monday that they expect the transaction to close in the second or third quarter of this year.

The clinically most advanced product candidate of Ardea, a San Diego-based biotech firm focused on the development of small-molecule therapeutics, is lesinurad, a potential treatment for the chronic management of hyperuricaemia in patients with gout. The treatment currently is in Phase III development.

Lesinurad is a selective inhibitor of URAT1, a transporter in the proximal tubule cells of the kidney that regulates uric acid excretion from the body, which is being developed as an oral, once-daily gout treatment.

Filings for a New Drug Application (NDA) in the United States and a Marketing Authorisation Application (MAA) in the European Union for lesinurad are planned for the first half of 2014, according to AstraZeneca, which said it also plans to develop and commercialise lesinurad in China and Japan.

Also with the acquisition, AstraZeneca would also add to its pipeline RDEA3170, a next-generation selective URAT1 inhibitor now in Phase I development.

"This attractive Phase III program [for lesinurad] is an excellent opportunity to leverage AstraZeneca’s global specialty and primary care sales and marketing capabilities," stated David Brennan, chief executive officer of AstraZeneca. "The Ardea team has done a great job developing lesinurad, along with a promising next-generation gout program. These compounds have real potential to benefit patients."

According to the companies, the estimated 14.7 million diagnosed prevalent cases of chronic gout in major markets in 2009 are forecast to climb to 16.6 million in 2019.

"We are delighted to be joining AstraZeneca," commented Barry Quart, president and CEO of Ardea. "From our earliest interactions, we were impressed with the quality of AstraZeneca’s people, and we are confident their commercial strength and global reach will help realize the full potential of our programs. The Ardea team and I are committed to helping complete development and working to secure registration for lesinurad."