Chinese police have questioned two more AstraZeneca PLC employees in Shanghai. Reuters

AstraZeneca (NYSE:AZN), the UK's second-largest drug company announced on Monday that it agreed to buy privately owned respiratory drug company Pearl Therapeutics for up to $1.15 billion.

London's AstraZeneca, in a statement, said it will acquire 100 percent of Pearl’s shares for an initial consideration of $560 million and a deferred consideration of up to $450 million, which becomes payable if specified development and regulatory milestones mentioned in the deal are achieved. In addition, the company could also make sales-related payments of up to $140 million.

The acquisition of Redwood City, Calif.'s Pearl will give AstraZeneca a foothold in the fast-growing market for a new class of inhaler-based lung treatments.

“This technology platform will allow AstraZeneca to explore combinations of existing and novel technologies, including a triple fixed dose combination (LABA/LAMA and inhaled corticosteroid), which could be accelerated into Phase II clinical development,” AstraZeneca said in the statement.

This purchase is AstraZeneca’s second acquisition in two weeks following its agreement to buy New Jersey's Omthera Pharmaceuticals (NASDAQ:OMTH) for about $443 million. AstraZeneca is looking ahead to boost its market presence in the U.S. through acquisitions as its best-selling drugs have lost exclusivity and are facing tough competition from generic drugs.

“Pearl’s novel formulation technology, together with its development products and specialist expertise, are a great complement to AstraZeneca’s long-established capabilities in respiratory disease, one of our core therapy areas,” Pascal Soriot, AstraZeneca's CEO, said in the statement.

AstraZeneca is banking on Pearl’s lead product, PT003, a long-acting muscarinic antagonist (LAMA), to fill in a gap in its respiratory portfolio. However, the drug is expected to enter the market only in 2016, well behind similar drugs from its rivals GlaxoSmithKline Plc. (NYSE:GSK) and Novartis AG (NYSE:NVS).

“This is a sensible deal to try to fix a recognized gap in the pipeline,” Alistair Campbell, an analyst with Berenberg Bank, said in a note to investors, according to Bloomberg News. “AstraZeneca will be late to market and with no obvious differentiation, but there were few options left to the company,” he added.

AstraZeneca said the Pearl Therapeutics purchase will have no impact on its 2013 earnings forecast.