Halaven(TM) (Eribulin) Receives European Commission Approval for Advanced Breast Cancer

LONDON, March 22, 2011 - Eisai announced today that it has received approval from the European
Commission for Halaven(TM) (Eribulin) for the treatment of patients with
locally advanced or metastatic breast cancer who have progressed after at
least two chemotherapeutic regimens for advanced disease. Prior therapy
should have included an anthracycline and a taxane unless patients were not
suitable for these treatments. Halaven is a new class of agent which provides
statistically significant overall survival improvements compared with current
treatment options.[1],[2]

The European Commission approval of Halaven was granted through a
centralised procedure, which means that the treatment has now been granted
marketing authorisation in the 27 EU member states. Halaven will be launched
in the EU during April 2011.

The approval of European Commission is 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
demonstrated a statistically significant increase in overall survival (OS)
for patients treated with Halaven when compared with TPC[a]. The protocol
prespecified analysis at the point of 422 events demonstrated a median OS of
13.1 and 10.6 months, respectively (Hazard Ratio [HR] 0.81; p=0.041);[1]
the updated analysis requested by European and US regulatory authorities
including 589 events demonstrated a median OS of 13.2 and 10.5 months,
respectively (HR 0.81; nominal p=0.014).[2]

Halaven is the first single-agent therapy to demonstrate a significant
overall survival benefit in patients with advanced breast cancer. The
European Commission approval means that patients across the EU will soon be
able to benefit from this treatment, which offers them an average of more
than 2 months longer life.

Halaven was approved in the USA in November 2010 and Singapore in
February 2011, and has already been launched in USA.The approval by
European Commission is the third in the world, other applications are
currently under review in Japan, Switzerland and Canada.

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 small molecules, biologic 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.

[a] Treatment of Physician's Choice (TPC) is 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.

NOTES TO EDITORS

About Halaven(TM)

Halaven is a non-taxane, microtubule dynamics inhibitor, belonging to a
class of antineoplastic agents, the halichondrins, which are natural products
isolated from the marine sponge Halichondria okadai.[3,4] Halaven targets
microtubules, the major cytoskeletal component of cells which play a pivotal
role in cell replication. Alteration of microtubule dynamics can cause a cell
to stop dividing and self destruct.

Geographical exploratory subgroup analyses demonstrated that Halaven
significantly improved OS in region 1 (North America, Western Europe &
Australia) compared with TPC (median 13.1 and 10.1 months, respectively;
p=0.009; HR 0.72).[1]

About EMBRACE

EMBRACE was an open-label, randomised, multi-centre study of 762 women
with MBC who were previously treated with at least two and a maximum of five
prior chemotherapies (greater than or equal to 2 for advanced disease),
including an anthracycline and a taxane. Patients must have been refractory
to the most recent chemotherapy, documented by progression on or within six
months of therapy. The study was designed to compare OS in patients treated
with Halaven versus a TPC arm, reflecting a real-world clinical setting where
a variety of agents are used to treat patients. The primary endpoint was OS.
Secondary endpoints were objective response rate, progression-free survival,
safety and duration of response.[1]

About Metastatic Breast Cancer

Worldwide, more than one million women a year are diagnosed with breast
cancer, including 421,000 women in Europe.[5,6] Approximately 30 percent of
women initially diagnosed with earlier stages of breast cancer eventually
develop recurrent or metastatic disease,[7] and while around 9 out of 10 of
women diagnosed with early stage breast cancer survive beyond five years,
this drops to around 1 in 10 among women first diagnosed with MBC.[8] Most
MBC patients have a limited survival time of approximately 18-24 months.[9]

Eisai in Oncology

Eisai is dedicated to discovering, developing and producing innovative
oncology therapies that can make a difference and impact the lives of
patients and their families. This passion for people is part of Eisai's human
health care (hhc) mission, which strives for better understanding of the
needs of patients and their families to increase the benefits health care
provides. Our 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 small molecules, therapeutic
vaccines, biologic and supportive care agents for cancer across multiple
indications.

Eisai Europe Limited

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; vaccines, tumor
regression, tumor suppression, antibodies and supportive cancer therapies;
pain relief, nausea

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

In Europe, Eisai undertakes sales and marketing operations in over 20
markets.

Eisai

Eisai 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 health care system.
Eisai employs approximately 11,000 employees worldwide.

For further information, please visit www.eisai.co.jp.

———————————

1 Cortes J, O'Shaughnessy J, Loesch D, et al. A Phase III open-label
randomized study (EMBRACE) or eribulin monotherapy versus treatment of
physician's choice in patients with metastatic breast cancer. The Lancet.
2011; 377: 914 -923

2 Twelves C et al. Updated Survival Analysis of a Phase III Study
(EMBRACE) of Eribulin Mesylate Versus Treatment of Physician's Choice in
Subjects with Locally Recurrent or Metastatic Breast Cancer Previously
Treated with an Anthracycline and a Taxane. San Antonio Breast Cancer
Symposium (SABCS) 2010; Poster P6-14-18.

3 Kuznetsov G, Towle MJ, Cheng H, et al: Induction of morphological and
biochemical apoptosis following prolonged mitotic blockage by halichondrin B
macrocyclic ketone analog E7389. Cancer Res 2004; 64: 5760-5766

4 Towle MJ, et al. In Vitro and In Vivo Anticancer Activities of
Synthetic Macrocyclic Ketone Analogues of Halichondrin B. Cancer Res 2001;
61: 1013-1021

5 Coughlin, S. Breast cancer as a global health concern. Cancer
Epidemiology, October 2009; 33: 315-18.

6 Ferlay J, Parkin DM, Steliarova-Foucher E. Estimates of cancer
incidence and mortality in Europe in 2008. Eur J Cancer.2010: 46(4):765-781

7 O'Shaughnessy J. Extending survival with chemotherapy in metastatic
breast cancer. Oncologist. 2005;10 Suppl 3:20-29

8 Cancer Research UK, Breast Cancer Statistics - Key Facts [updated April
2010]. Available from:
info.cancerresearchuk.org/cancerstats/types/breast/index.htm?script=true
(accessed (04/08/10)

9 Fernandez Y, Cueva J, Palomo AG, et al. Novel therapeutic approaches to
the treatment of metastatic breast cancer. Cancer Treat Rev.2010:36(1):33-42

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Media Enquiries, Eisai Europe Ltd, Cressida Robson, +44-7908-314-155, Cressida_Robson at eisai.net; Ingenda Communications, Robyn Cabarrao, +44-7913-216-896, RCabarrao at ingendacommunications.com