French drugmaker Sanofi-Aventis has agreed to buy the stake it does not already own in the Merial animal healthcare business from its U.S. partner Merck & Co, Bloomberg News said on Wednesday.

No one at Sanofi was immediately available to comment.

The acquisition is set to be announced this week, two people familiar with the situation told the news agency. They did not disclose the price of the transaction.

At Sanofi's results news conference earlier on Wednesday Chief Executive Chris Viehbacher repeated that Sanofi was interested in expanding its animal health business but declined to comment specifically on Merial.

Viehbacher had already said in April he was open to buying Merck's part of Merial.

Since Merck's announced takeover of Schering Plough, Sanofi has been widely seen as in pole position to buy the stake as it looks to diversify its business to help offset a looming loss in drug sales due to patent expiries.

(Reporting by Caroline Jacobs; Editing by Greg Mahlich)

Merck & Co.