Roche, for its part, is facing generic competition on Accutane, one of its best-selling acne drugs.

FORBES: Roche And Schering's Desperate Duel

Many are coming off patent and being distributed and produced, in large part, by the generic drug makers.

FORBES: What Amgen Faces in Brazil

Pharmacy same-store sales were negatively impacted by the decrease in Medicare Part D patients, recent generic introductions and the loss of certain contracts with large clients.

FORBES: Magazine Article