New Breast Cancer Treatment Launches in Sweden, Denmark and Finland

Halaven(TM) Offers Statistically Significant Survival Benefit for Women With Heavily Pre-treated Locally Advanced or Metastatic Breast Cancer

HATFIELD, England, April 20, 2011 - Halaven(TM) (eribulin), a novel treatment for patients with
locally advanced or metastatic breast cancer who have progressed after at
least two chemotherapeutic regimens for advanced disease is launched today in
Sweden, Denmark and Finland after approval by the European Drug Agency (EU)
for the whole EU area by March 24, 2011. Prior therapy should have included
two common types of chemotherapy, an anthracycline and a taxane, unless
patients were not suitable for these treatments.[1]

Discovered and developed by Eisai, Halaven is a non-taxane
microtubule dynamics inhibitor and a synthetic analog of halichondrin B, a
natural product isolated from the marine sponge Halichondria okadai.[2] It is
a new class of agent and the first, single-agent chemotherapy to demonstrate
a statistically significant overall survival benefit in patients with heavily
pre-treated advanced breast cancer compared to currently used treatments.[1],
[3]

Breast cancer is the most common cancer in women in Nordic
countries representing 27 percent of cancer cases in 2008 corresponding to an
annual incidence of approximately 17,300 women getting a breast cancer
diagnosis per year.[4] It accounts for around 15 percent of female deaths
from cancer.[4] The prognosis for primary breast cancer has improved markedly
over the years, while the outcome for metastatic breast cancer is still
bleak, the approved indication for Halaven. Around five percent of breast
cancer patients present with advanced disease with distant metastases at
first diagnosis,[5] and 20 - 30 percent of women diagnosed with early or
localised breast cancer will eventually relapse and develop metastatic or
advanced disease.[6]

"The launch of Halaven in Sweden, Denmark and Finland will be an
interesting and potentially important amendment to the present therapy
armamentarium for the management of patients failing on conventional
therapies," commented Professor Jonas Bergh, Karolinska Institutet and
University Hospital, Sweden. "Compared to current treatment options, Halaven
is the first single chemotherapy agent to have demonstrated a statistically
significant improvement in median overall survival for many patients who have
already received several lines of therapy for advanced breast cancer."

Halaven received European Commission approval based on the
results of the global Phase III EMBRACE study (Eisai Metastatic Breast Cancer
Study Assessing Treatment of Physician's Choice (TPC) Versus Eribulin E7389)
which showed that patients treated with Halaven survived a median of 2.5
months longer than patients who received treatment of physician's choice
(overall survival of 13.1 months versus 10.6 months, respectively,
p=0.041).[1],[3]

The most common reported adverse reactions among patients treated
with Halaven were asthenia (fatigue), neutropenia, alopecia (hair loss),
peripheral neuropathy (numbness and tingling in arms and legs), nausea and
constipation.[3]

Eisai's commitment to meaningful progress in oncology research,
built on scientific expertise, is supported by a global capability to conduct
discovery and preclinical research, and develop low molecular weight organic
compounds, therapeutic vaccines, monoclonal antibody-based therapies,
biologics, and supportive care agents for cancer across multiple indications.
Through these efforts, Eisai will make further contributions to addressing
the diversified needs of and increasing the benefits provided to patients and
their families as well as healthcare professionals as it seeks to fulfill its
human health care (hhc) mission.

Notes to Editors

Halaven is the EU trade name for eribulin.

Global Phase III Clinical Study (EMBRACE)

EMBRACE was an open-label, randomised, global, multi-centre, parallel
two-arm study designed to compare overall survival in patients treated with
Halaven versus a Treatment of Physician's Choice (TPC arm). TPC was defined
as any single-agent chemotherapy, hormonal treatment or biologic therapy
approved for the treatment of cancer; or palliative treatment or radiotherapy
administered according to local practice. The study included 762 patients
with metastatic breast cancer who previously had been treated with at least
two and a maximum of five prior chemotherapies, including an anthracycline
and a taxane. The vast majority (97%) of patients in the TPC arm received
chemotherapy.[3]

The most common adverse reactions (incidence greater than or equal to
19%) among patients treated with Halaven were asthenia (fatigue),
neutropenia, alopecia (hair loss), peripheral neuropathy (numbness and
tingling in arms and legs), nausea and constipation. The most common serious
side effect reported in patients receiving Halaven was neutropenia, with or
without fever (occurring in 45% and 5% of patients respectively).[3] The most
common adverse reaction resulting in discontinuation of treatment with
Halaven(TM) was peripheral neuropathy (five percent).[3]

Metastatic Breast Cancer

In 2008, approximately 17,300 women were diagnosed with breast cancer in
the Nordic region, and approximately 4,250 women died from breast cancer.[4]

Yearly incidence of breast cancer per country:[4]

- Sweden: 6,315 women

- Denmark: 4,149 women

- Finland: 3,922 women

Metastatic breast cancer is an advanced stage of the disease that occurs
when cancer spreads beyond the breast to other parts of the body.
Approximately five percent of women with breast cancer will have metastatic
disease at the time of diagnosis[5] and others with local and regional disease
may eventually develop metastatic disease.[6] An estimated 13 percent of women
presenting with metastatic breast cancer will survive beyond five years.[5]

Halaven(TM) (eribulin)

Halaven is a non-taxane, microtubule dynamics inhibitor indicated for the
treatment of patients with breast cancer who have previously received at
least two chemotherapeutic regimens for metastatic disease and whose prior
therapy should have included an anthracycline and a taxane.[1] Halaven
belongs to a class of antineoplastic agents, the halichondrins, which are
natural products, isolated from the marine sponge Halichondria okadai. It is
believed to work by inhibiting the growth phase of microtubule dynamics
without affecting the shortening phase and sequesters tubulin into
non-productive aggregates.

About Eisai

Eisai is one of the world's leading R&D-based pharmaceutical
companies that 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: Alzheimer's disease, multiple sclerosis,
neuropathic pain, epilepsy, depression, etc

- Integrative Oncology: Anticancer therapies; tumour regression, tumour
suppression, antibodies, etc and Supportive cancer therapies; pain relief,
nausea, etc

- Vascular/Immunological Reaction: Acute coronary syndrome,
atherothrombotic disease, sepsis, rheumatoid arthritis, psoriasis, Crohn's
disease, etc

With operations in the U.S., Asia, Europe and its domestic
home market of Japan, we employ more than 10,000 people worldwide, and
reported consolidated sales of over GBP3.53 billion in FY2007, an increase of
8.9% year on year. 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, Slovakia and the Netherlands.

For further information please visit our web site www.eisai.com

References

[1] Summary of Product Characteristics Halaven (updated March
2011)

[2] Jordan MA et al. The primary antimitotic mechanism of action
of the synthetic halichondrin E7389 is suppression of microtubule growth. Mol
Cancer Ther 2005;4:1086-95

[3] Cortes J, O'Shaughnessy J, Loesch D, et al. Eribulin
monotherapy versus treatment of physician's choice in patients with
metastatic breast cancer (EMBRACE): a phase 3 open-label randomised study.The
Lancet. 2011; 377: 914 -923

[4] NORDCAN 2009. Available from URL
www-dep.iarc.fr/NORDCAN/english/frame.asp (Accessed 4 April 2011)

[5] Cancer Research UK. Statistics and outlook for breast cancer.
Available from URL
www.cancerhelp.org.uk/type/breast-cancer/treatment/statistics-and-outlook-for-breast-cancer
(Accessed 1 April 2011)

[6] O'Shaughnessy, J. Extending Survival with Chemotherapy in Metastatic
Breast Cancer. The Oncologist. 2005;10;20-29

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Eisai Europe Ltd, Cressida Robson, +44-7908-314-155, Cressida_Robson at eisai.net Tonic Life Communications, Benjamyn Tan / Helen Swift, +44(0)207-798-9262 / +44(0)7792-034-191, benjamyn.tan at toniclc.com helen.swift at toniclc.com