Watson Pharmaceuticals Inc. has become the fourth generics maker hit with a patent suit by Cephalon Inc. for planning to offer a generic version of narcolepsy drug Nuvigil®. Cephalon filed suit against Watson on January 5, alleging that Watson’s abbreviated new drug application for generic Nuvigil® infringes a Cephalon patent. Cephalon had previously filed similar suits over planned generic Nuvigil® against Mylan Pharmaceuticals Inc., Actavis Group and Teva Pharmaceuticals USA Inc. Nuvigil® is a prescription drug used to improve wakefulness in patients with excessive sleepiness associated with narcolepsy, sleep apnea, and shift work sleep disorder. Cephalon is represented in this matter by Finnegan.