Sanofi Aventis

The FDA disappointed AstraZeneca and its investors by not approving its heart drug Brilinta, a blood-thinner that the company -- facing a severe patent cliff -- has high hopes for. If approved, it could be a multibillion-dollar blockbuster. But the FDA wants to see more analyses of results from a major study.

More than a year after AstraZeneca filed for approval, the FDA will make its decision on Thursday. A large study showed the blood thinner worked better than Plavix for treating acute coronary syndrome -- but approval isn't a sure thing, due in part to some oddities in the study's results.

Paris-based pharma Sanofi-Aventis has pushed back its offer deadline for Massachusetts-based biotech Genzyme by six weeks. All other terms, including the $69 per share bid, remain unchanged. So far, very few shareholders have responded.

By the time the world's smartest investors tell the SEC what stocks they hold, most of the gains they were after are already priced in. But a few of the companies Warren Buffett, George Soros, and their billionaire buddies have bought into still have a lot further to rise. Which ones? Read on ...

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.

Genzyme, which makes drugs to treat leukemia and multiple sclerosis, has rejected a hostile takeover bid from French drugmaker Sanofi-Aventis. The offer "dramatically undervalues" Genzyme, the company said Friday, putting its value about 30% higher.

French pharmaceutical giant Sanofi-Aventis says its multiple sclerosis drug teriflunomide significantly cut relapses in patients who took the once-daily oral treatment.