Woodcliff Lake, NJ, August 30, 2011 - Results presented today of a Phase III pivotal study for the investigational compound perampanel for partial-onset seizures showed that perampanel, 8 mg and 12 mg, produced statistically significant reductions in median seizure frequency compared to placebo among patients having partial-onset seizures while receiving treatment with one to three other epilepsy drugs. The results were presented at the 2011 International Epilepsy Congress. Perampanel is a highly selective non-competitive AMPA-type glutamate receptor antagonist discovered and being developed by Eisai.

In Study 305, the response rates (defined as 50 percent or greater reduction in seizure frequency) were 14.7 percent for placebo, 33.3 percent for 8mg (p=0.002) and 33.9 percent for 12 mg (p=<0.001). Study results also showed that perampanel 8 mg once-daily reduced median seizure frequency by 30.5 percent (p=0.001) and perampanel 12 mg once-daily reduced median seizure frequency by 17.6 percent (p=0.0011) vs placebo (9.7 percent) among patients receiving treatment with one to three other epilepsy drugs. The most commonly reported treatment-emergent adverse events occurring in Study 305 in 10 percent or more of patients included dizziness, fatigue, headache and somnolence. Discontinuations due to treatment emergent adverse events were 4.4 percent for placebo, 9.3 percent for the 8mg dose of perampanel, and 19 percent for the 12mg dose of perampanel.

"This third Phase III study demonstrated the statistical and clinical efficacy of perampanel for reducing partial-onset seizures among epilepsy patients," said Lynn D. Kramer, MD, FAAN, President, Eisai Neuroscience Product Creation Unit. "Eisai is committed to developing new therapies that can offer seizure control and address unmet medical needs, as part of our hhc (human health care) corporate mission."

About Study 305
Study 305 is the final of three Phase III studies in the EXPLORE (EXamining Perampanel Observations from Research Experience) clinical trial program. The study design was consistent among all three studies: global randomized, double-blind, placebo-controlled, dose-escalation, parallel group studies in which 1,480 epilepsy patients participated. Study 305 involved 389 people (386 evaluated in the full intent to treat analysis) in the United States, European Union, Asia, Australia and South Africa who had uncontrolled epilepsy and were currently taking one to three other epilepsy drugs. Participants were assigned to receive either 8 mg or 12 mg of perampanel or placebo once daily for 19 weeks (6 weeks of titration, 13 weeks of maintenance therapy) in addition to their regular treatment. The primary and secondary endpoints were: standard median percent seizure reduction, 50 percent responder rate, percentage reduction of complex partial plus secondarily generalized seizures and evaluation for dose response. Median seizure frequency and change in responder rate were the primary outcome measures in the U.S. and EU, respectively. The most commonly reported treatment-emergent adverse events occurring in Study 305 in 10 percent or more of patients included dizziness, fatigue, headache and somnolence.

About Perampanel
Perampanel is an orally administered, highly selective non-competitive AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid)-type glutamate receptor antagonist discovered and being developed by Eisai. The AMPA receptor is widely present in almost all excitatory neurons.

About Eisai Inc.
Eisai Inc. was established in 1995 and is ranked among the top-20 U.S. pharmaceutical companies (based on retail sales). The company began marketing its first product in the United States in 1997 and has rapidly grown to become a fully integrated pharmaceutical business. Eisai's areas of commercial focus include neurology, gastrointestinal disorders and oncology/critical care. The company serves as the U.S. pharmaceutical operation of Eisai Co., Ltd., a research-based human health care (hhc) company that discovers, develops and markets products throughout the world.

Eisai has a global product creation organization that includes U.S.-based R&D facilities in Massachusetts, New Jersey, North Carolina and Pennsylvania as well as manufacturing facilities in Maryland and North Carolina. The company's areas of R&D focus include neuroscience; oncology; vascular, inflammatory and immunological reaction; and antibody-based programs. For more information about Eisai, please visit www.eisai.com/US.

About Eisai Co., Ltd.
Eisai Co., Ltd. is a research-based human health care (hhc) company that discovers, develops and markets products throughout the world. Through a global network of research facilities, manufacturing sites and marketing subsidiaries, Eisai actively participates in all aspects of the worldwide healthcare system. Eisai employs approximately 11,000 employees worldwide.