Helsinn Healthcare S.A. and Eisai Inc. Extend Relationship

Enter U.S. Licence and Co-promotion Agreement for Potential New Therapy in the Prevention of Chemotherapy-induced Nausea and Vomiting (CINV)

LUGANO, Switzerland and WOODCLIFF LAKE, New Jersey, June 9, 2010 - Helsinn Healthcare S.A. and Eisai Inc. today announce the
signing of a licensing agreement granting Eisai Inc. commercialization rights
for a new product for potential use in the prevention of chemotherapy-induced
nausea and vomiting (CINV) in the United States. The arrangement covers the
development of a fixed-dose combination product (in both oral and IV forms)
containing netupitant, a neurokinin-1 (NK1) receptor antagonist, and
palonosetron, a serotonin-3 (5-HT3) receptor antagonist.

Under the terms of the agreement, Helsinn Healthcare S.A. will
be responsible for conducting all development activities (CMC, preclinical
and clinical), obtaining regulatory approvals, and holding the New Drug
Application. If approved by the Food and Drug Administration, the fixed dose
combination oral and IV products will be co-promoted in the United States by
Eisai Inc. and Helsinn Therapeutics (U.S.) Inc. Helsinn's manufacturing
affiliate in Ireland, Helsinn Birex Pharmaceuticals Ltd., will be responsible
for the manufacture and supply of finished product for clinical and
commercial use in the United States.

In addition, Helsinn Therapeutics (U.S.) Inc. has signed a
Detail Service Agreement with Eisai Inc. to co-promote the existing brand
Aloxi(R) (palonosetron hydrochloride) in the U.S. market. As a result,
Helsinn Therapeutics (U.S.) Inc. will recruit and hire a dedicated sales
force to visit primarily clinical oncologists in the United States.

Riccardo Braglia, CEO of Helsinn group, said: "We are very
proud that the existing successful collaboration with Eisai Inc. in the U.S.
for Aloxi(R) is now extending to a co-promotion of Aloxi(R) and, if approved,
to Netupitant-Palonosetron FDC, and the strengths of our two companies will
enable patients to have additional treatments for CINV now and in the
future."

"Eisai is committed to satisfying unmet medical needs and
contributing to the health and well-being of people worldwide," said Lonnel
Coats, President and COO of Eisai Inc. "Our expanded relationship with
Helsinn further demonstrates our focus on oncology and supportive care and
will help to strengthen our presence in the area of anti-emesis therapy."

About Netupitant

Netupitant is a highly selective NK1 receptor antagonist, an
antiemetic that works by blocking the action of Substance P, an endogenous
neurotransmitter contained in high concentrations in the vomiting center of
the brainstem that can stimulate the vomiting reflex. The fixed-dose
combination of netupitant and palonosetron is entering Phase III for the
prevention of acute and delayed nausea and vomiting following both highly and
moderately emetogenic chemotherapy.

About Aloxi(R)

About Palonosetron (Aloxi(R), Onicit(R), Paloxi(R))

Palonosetron hydrochloride is a selective 5-HT3 receptor
antagonist, developed for the prevention of chemotherapy-induced nausea and
vomiting (CINV) in patients with cancer, with a long half-life of 40 hours
and at least 30 times higher receptor binding affinity than currently
available compounds. Palonosetron demonstrates, in clinical trials and
clinical practice, a unique long-lasting action in the prevention of CINV.
The product has shown to be effective in preventing both Day 1 and Days 2-5
CINV in patients receiving moderately emetogenic chemotherapies (MEC). A
single intravenous dose of palonosetron (0.25 mg) provides better protection
from CINV than first-generation 5-HT3 receptor antagonists throughout a 5-day
post-chemotherapy period in MEC setting. This means that a single
administration of palonosetron also grants protection during the Days 2-5
phase of CINV.

Palonosetron is contraindicated in patients known to have
hypersensitivity to the drug or any of its components. The most commonly
reported adverse reactions (incidence greater than or equal to percent) in
CINV trials with palonosetron were headache (9 percent) and constipation (5
percent), and they were similar to the comparators.

For indications and dosages in your country, please refer to
the Summary of Product Characteristics approved by your local authorities.

Palonosetron has been developed by Helsinn Group of
Switzerland and today it is marketed as Aloxi(R), Onicit(R), and Paloxi(R) in
more than 50 countries world-wide.

In the EU, palonosetron is marketed as Aloxi(R) through a
distribution license granted by Helsinn to several pharmaceutical companies.

For more information about palonosetron please visit the
website www.aloxi.com

About the Helsinn Group

Helsinn is a privately owned pharmaceutical group with
headquarters in Lugano, Switzerland, and operating subsidiaries in Ireland
and USA. Helsinn's

business model is focused on the licensing of pharmaceuticals
and medical devices in therapeutic niche areas. The Group in-licenses early
to late stage new chemical entities, completes their development from the
performance of

pre-clinical/clinical studies and Chemistry, Manufacturing and
Control (CMC), development to the filing for and attainment of their market
approval worldwide. Helsinn's products are sold directly through the Group's
subsidiaries or out-licensed to its network of local marketing and commercial
partners, selected for their deep in-market knowledge and know-how, and
assisted and supported with a full range of product and scientific management
services, including commercial, regulatory, financial, legal and medical
marketing advice. The active pharmaceutical ingredients and the finished
dosage forms are manufactured at Helsinn's cGMP facilities in Switzerland and
Ireland, and supplied worldwide to its customers. For more information about
Helsinn Group, please visit the website: www.helsinn.com

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 with
fiscal year 2009 (year ended March 31, 2010) sales of approximately $3.9
billion. 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.

Eisai has a global product creation organization that includes
U.S.-based R&D facilities in Maryland, 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.

    Paola Bonvicini
    Head of Communication & Press Office
    Helsinn Healthcare SA
    Ph: +41-91-985-21-21
    info-hhc@helsinn.com

    Lynn Kenney
    Corporate Communications
    Eisai Inc.
    Ph: +1-201-746-2294
    lynn_kenney@eisai.com

Paola Bonvicini, Head of Communication & Press Office, Helsinn Healthcare SA, Ph: +41-91-985-21-21, info-hhc at helsinn.com; Lynn Kenney, Corporate Communications, Eisai Inc., Ph: +1-201-746-2294, lynn_kenney at eisai.com