AstraZeneca senior director of public affairs Steve Lampert said the agencies will work across the firm's entire disease categories.
Edelman won the company's cardiovascular and central nervous system business.
The gastrointestinal category, which includes the Nexium brand, was retained by F-H, which had handled the business for the past eight years.
B-M held onto oncology, which it has had for over a decade, and also picked up the respiratory business.
Signova was selected to work on managed care and drug assistance programmes.
'We're consolidating business to put ourselves in a better position to negotiate contracts with agencies,' Lampert explained.
As part of a company-wide procurement initiative, AstraZeneca put its entire product PR business up for bid at the end of last year.
Lampert said more than ten agencies responded to the RFPs. Of the four, Edelman picked up the biggest share of new business.
It will handle US comms for four brands: Seroquel for schizophrenia, Toprol-XL and Atacand for hypertension, and its investigational oral anticoagulant, Exanta.
Edelman has created a post overseeing its entire European consumer PR operation, promoting Cornelia Kunze to the role. Kunze, who remains in her current role as head of the agency's Hamburg office, takes on responsibility for consumer teams in the UK, France, Germany, Spain, Ireland, Belgium, Sweden, the Netherlands and Luxembourg.