U.S., Canada reviewing Nexium, see no heart risk

The FDA's primary focus is on Nexium and Prilosec, but officials are interested in data from other drugs in the class, said Dr. Paul Seligman, associate director of the safety policy and communication in the FDA drugs center.

Nexium sales already fell short of some expectations in the most recent quarter at $1.31 billion.

AstraZeneca has endured a series of late-stage product setbacks and made acquisitions to rebuild its pipeline. Last month, the company said it would eliminate 7,600 jobs as part of an expanded cost-cutting drive. (Additional reporting by Kim Dixon and Jessica Wohl in Chicago, Lewis Krauskopf in New York and Michael Kahn in London)