LONDON - AstraZeneca PLC says the U.S. Food and Drug Administration has asked for more information about a new drug for ulcers and a proposed new use for its best-selling ulcer treatment Nexium.

Tuesday's revelation that the FDA has sought more information in so-called complete response letters is a setback to the British company's attempts to expand its drugs cabinet.

AstraZeneca had sought approval for Axanum, a new medicine combining aspirin and esomeprazole, the main ingredient in Nexium, to prevent ulcers of the stomach and duodenum.

It had also asked to market Nexium to reduce the risk of low-dose aspirin associated peptic ulcers.

AstraZeneca says it will discuss its next steps with the FDA and will respond to the requests for additional information.

The company, which is based outside London, has U.S. headquarters near Wilmington and a division in the Philadelphia area.

Company shares were priced at $42.80, up 55 cents, late this morning on the New York Stock Exchange.