Amgen ($AMGN) wants to do everything that it can to protect its top-selling anti-inflammatory drug Enbrel from the advent of biosimilars, and now, it's shoring up its defenses. The company slapped Novartis' ($NVS) Sandoz unit with a patent infringement suit, claiming that Sandoz's Enbrel biosimilar violates a few of its patents for the med. The suit could help Amgen hold on to sales of Enbrel, which brought in $5 billion last year for the company. Read more at FiercePharma