Most of the news reports about yesterday's oral argument in Comcast Corp. v. Behrend pointed out that a second case involving class action issues was also argued yesterday. The case is Amgen Inc. v. Connecticut Retirement Plans and Trust Funds, no.11-1085, and the argument transcript is available at this link.
Amgen is a securities class action and the questions presented have to do with materiality and the "fraud on the market" theory.
The news reports I've seen so far contain little substantive analysis of the two arguments. Reports are available from The New York Times, The Washington Post, Bloomberg News, Business Week, and Reuters.