Eisai Announces Positive Phase III Trial Results for Perampanel in Partial Epilepsy

HATFIELD, England, August 24, 2010 - Eisai today announced the results of a Phase III study for the
investigational compound perampanel (E2007), a first-in-class, highly
selective non-competitive AMPA-type glutamate receptor antagonist, discovered
by Eisai and under development for adjunctive treatment of partial seizures
in patients with epilepsy.

The double-blind, placebo-controlled, parallel-group study (Study 306)
showed that perampanel was well-tolerated and effective in reducing median
seizure frequency and increasing responder rates versus placebo, the primary
outcome measures in the U.S. and the E.U., respectively. The findings were
statistically significant in 4 mg and 8 mg doses compared to placebo. A
linear trend for dose response was also statistically significant.

The global study consisted of 706 patients from 25 countries who were
randomized to placebo or one of three perampanel doses. Patients started on 2
mg doses of perampanel, then remained on 2 mg or increased dosage weekly in 2
mg increments to their randomized doses of 4 mg or 8 mg. The most common
adverse events reported were dizziness, somnolence and headache.

Study 306 is the first in a series of Phase III clinical trials as part
of Eisai's development program for perampanel and two more global Phase III
studies for adjunctive therapy in partial seizures are underway. Eisai plans
to submit the studies as part of global applications, and results are
expected to be available within one year.

As previously announced, Eisai intends to submit simultaneously in the
U.S. and E.U. in our Fiscal Year 2011.

About Eisai Europe in Epilepsy

Eisai is committed to making further contributions to addressing the
diversified needs and improving quality of life of patients with epilepsy.
Eisai has three currently marketed treatments in Europe, these are:

    - Zonegran(R) as adjunctive therapy in adult patients with partial-onset
      seizures, with or without secondary generalisation

    - Zebinix(R) (eslicarbazepine acetate) (under license from Bial - Portela
      & Ca, S.A in Europe) as adjunctive therapy in adult patients with
      partial-onset seizures, with or without secondary generalisation

    - Inovelon(R) for the treatment of seizures associated with
      Lennox-Gastaut Syndrome

About Eisai

Eisai is one of the worlds leading R&D-based pharmaceutical companies and
has defined its corporate mission as "giving first thought to patients and
their families and to increasing the benefits health care provides," which we
call human health care (hhc).

Eisai concentrates its R&D activities in three key areas:

    - Integrative Neuroscience, including: Alzheimer's disease, multiple
      sclerosis, neuropathic pain, epilepsy, depression

    - Integrative Oncology including: anticancer therapies; tumor regression,
      tumor suppression, antibodies, etc and supportive cancer therapies;
      pain relief, nausea

    - Vascular/Immunological reaction including: acute coronary syndrome,
      atherothrombotic disease, severe sepsis, rheumatoid arthritis,
      psoriasis, Crohn's disease

With operations in the U.S., Asia, Europe and its domestic home market of
Japan, we employ more than 11,000 people worldwide.

In Europe, Eisai undertakes sales and marketing operations in over 20
markets, including the United Kingdom, France, Germany, Italy, Spain,
Switzerland, Sweden, Ireland, Austria, Denmark, Finland, Norway, Portugal,
Iceland, Czech Republic, Hungary, and Slovakia.

For further information please visit our web site www.eisai.co.jp

Media Inquiries: Cressida Robson, Eisai Europe Ltd., cressida_robson at eisai.net , +44-7908-314-155.