Novartis and Novo Nordisk are ganging up on Bayer, alleging that the German company's hemophilia treatment Kogenate infringes on one of their joint patents. In a statement, Bayer said it would "vigorously defend itself" against the complaint, and that it doesn't believe it has overstepped the bounds of any patents. The company's stock fell on the news. Meanwhile, other news reports said the suit, filed in federal court in Texas, names Wyeth as well. The New Jersey-based firm has not yet commented.