Sanofi-Aventis earnings

What is preventing the French pharmaceutical group and U.S. biotech from reaching a merger agreement?

Big Pharma didn't rest Thursday, with Celgene, Sanofi-Aventis and AstraZeneca among the big names reporting earnings. A deal between Stryker and Boston Scientific and Sanofi and BMP Sunstone also made the headlines, as did some hiring from Teva. Bristol-Myers Squibb received the anticipated new approval for one of its cancer drugs. But it was Celgene that led drug stocks higher.

On Thursday, Sanofi-Aventis reported its second-quarter net profit rose 7.6% to 2.48 billion euros, beating expectations. But the French drugmaker warned that earnings may fall for the full year, and it remained silent about its rumored plan to make a friendly bid for Genzyme.