London - AstraZeneca has agreed to buy Actavis' branded respiratory drug business in the United States and Canada for an initial $600m as it seeks external deals to ensure growth.
AstraZeneca will also pay another $100m, after Actavis agreed to a number of changes to ongoing agreements between the two firms.
Thursday's announcement came as Britain's second-biggest drugmaker posted fourth-quarter results that fell short of expectations and said 2015 sales revenue would decline by a mid single-digit percent at constant exchange rates.
Core earnings per share, however, are forecast to increase by a low single-digit percent this year.
Shares in the company slid 2% in early trade.
The British group, which saw off a $118bn bid by Pfizer last year, said its sales in the fourth quarter fell 2% to $6.68bn, generating core earnings down 38% at 76 cents a share.
Industry analysts had on average forecast sales in the quarter of $6.79bn and earnings of 82 cents a share, according to Thomson Reuters.
Buying the Actavis respiratory drugs builds on AstraZeneca's acquisition of Almirall's lung drugs last July and gives it global rights to inhaled medicines containing aclidinium, which helps open airways. Actavis had owned North American rights under an earlier agreement with Almirall.
Respiratory is a key therapeutic area for AstraZeneca, whose chief executive Pascal Soriot is determined to show his company has a strong independent future.
AstraZeneca has won over many investors with its line-up of new cancer drugs but it faces near-term pressure on profits from cheap generic copies of older drugs, with the arrival of copies of its heartburn and ulcer medicine Nexium in the United States a big challenge in 2015.
Nexium lost US exclusivity at the end of May 2014 but a generic version is only now set to reach the market. The recent green light for Teva's generic follows manufacturing problems at India's Ranbaxy, which had been in line to market the first copycat version.
Although sales are set to slide again this year, shareholders may take some heart from AstraZeneca's forecasts that core earnings are set to increase from the $4.28 reported for 2014.
Soriot and his team have good reason to ensure earnings do not slip, since management incentives only vest fully if EPS remains at or above $4.20.