Edoxaban Demonstrates Superior Efficacy Compared With Enoxaparin Sodium in Preventing VTE After Total Hip Replacement

TOKYO, December 8, 2010 - Daiichi Sankyo Company, Limited announced that its
investigational once-daily oral, direct factor Xa inhibitor, edoxaban, was
shown to be superior to enoxaparin sodium in preventing venous thromboembolic
(VTE) events in patients following total hip replacement (THR), a type of
major orthopedic surgery. Results from the Phase III STARS J-V (Studying
Thrombosis After Replacement Surgery) study[1] were presented at the 52nd
Annual Meeting of the American Society of Hematology in Orlando.[2]

This multicentre, double-blind, double dummy, centrally
randomised trial evaluated the efficacy and safety of edoxaban compared with
enoxaparin sodium in patients undergoing THR in Japan. A total of 610
patients received either 30 mg once-daily oral dose of edoxaban or
subcutaneous injection of enoxaparin sodium 2,000 international units
(equivalent to 20 mg) twice-daily for 11 to 14 days. The primary efficacy
endpoint of the trial was the incidence of symptomatic pulmonary embolism
(PE) and symptomatic and asymptomatic deep vein thrombosis (DVT). The primary
safety endpoint was the incidence of major bleeding and clinically relevant
non-major bleeding.

Asymptomatic DVT occurred in 2.4 percent of patients receiving
edoxaban once-daily compared with 6.9 percent of patients who received
enoxaparin sodium (relative risk reduction of 65.7 percent; p=0.016). There
were no PE events observed in either treatment group. There was no
statistically significant difference in major and clinically relevant
non-major bleeding (p=0.475). There were no cases of intracranial hemorrhage
or death in either treatment group.

Indicators for potential liver damage in both treatment groups
were carefully monitored during this trial by measuring bilirubin[3] and
serum aminotransferase levels.[4] Elevations greater than three times the
upper limit of the normal range of serum aminotransferase levels occurred in
2.6 percent of patients taking edoxaban compared with 10 percent of those
taking enoxaparin sodium.

In March 2010, Daiichi Sankyo submitted a New Drug Application
to the Ministry of Health, Labor and Welfare in Japan seeking approval of
edoxaban for the prevention of VTE after major orthopedic surgery.

About Edoxaban

Edoxaban is a once-daily oral anticoagulant that directly
inhibits factor Xa, an important factor in the coagulation process. Edoxaban
was discovered by Daiichi Sankyo and is currently in phase III of clinical
development. Daiichi Sankyo is developing edoxaban as a potential new
treatment for the prevention of both arterial and venous thromboembolism.
Notably, Daiichi Sankyo has more than 25 years experience conducting research
in the area of factor Xa inhibition, and was the first company to study these
compounds in humans. Edoxaban is being developed solely by Daiichi Sankyo.

About Daiichi Sankyo

The Daiichi Sankyo Group is dedicated to the creation and
supply of innovative pharmaceutical products to address the diversified,
unmet medical needs of patients in both mature and emerging markets. While
maintaining its portfolio of marketed pharmaceuticals for hypertension,
hyperlipidemia, and bacterial infections, the Group is engaged in the
development of treatments for thrombotic disorders and focused on the
discovery of novel oncology and cardiovascular-metabolic therapies.
Furthermore, the Daiichi Sankyo Group has created a "Hybrid Business Model,"
which will respond to market and customer diversity and optimise growth
opportunities across the value chain. For more information, please visit
www.daiichisankyo.com

Forward-looking statements

This press release contains forward-looking statements and
information about future developments in the sector, and the legal and
business conditions of DAIICHI SANKYO, Co. Ltd, DAIICHI SANKYO, Inc., and
DAIICHI SANKYO EUROPE GmbH. Such forward-looking statements are uncertain and
are subject at all times to the risks of change, particularly to the usual
risks faced by a global pharmaceutical company, including the impact of the
prices for products and raw materials, medication safety, changes in exchange
rates, government regulations, employee relations, taxes, political
instability and terrorism as well as the results of independent demands and
governmental inquiries that affect the affairs of the company. All
forward-looking statements contained in this release hold true as of the date
of publication. They do not represent any guarantee of future performance.
Actual events and developments could differ materially from the
forward-looking statements that are explicitly expressed or implied in these
statements. DAIICHI SANKYO, Co. Ltd, DAIICHI SANKYO, Inc., and DAIICHI SANKYO
EUROPE GmbH assume no responsibility for the updating of such forward-looking
statements about future developments of the sector, legal and business
conditions and the company.

References

[1] T. Fuji et al.,Efficacy and Safety of Edoxaban Versus Enoxaparin for
the Prevention of Venous Thromboembolism Following Total Hip Arthroplasty:
STARS J-V trial, December 4-7 2010, Orlando, Florida.

[2] 52nd ASH Annual Meeting and Exposition. Available at
ash.confex.com/ash/2010/webprogram/start.html#srch=words%7CEDOXABAN%20%7Cmethod%7Cand%7Cpge%7C1
Accessed December 3, 2010

[3] Medline Bilirubin. Available at
www.nlm.nih.gov/medlineplus/ency/article/003479.htm Accessed December
3, 2010

[4] Liver Blood Tests. Available at:
www.medicinenet.com/liver_blood_tests/page2.html Accessed June 18,
2010.

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For more information, please contact:

    Toshiaki Sai
    Daiichi Sankyo, Co., Ltd.
    (Japan)
     +81-3-6225-1126 (office)

    Dr. Michaela Paudler-Debus
    Daiichi Sankyo Europe GmbH
    +49-(0)89-78-08-685 (office)
    +49-(0)172-845-8974 (mobile)

Toshiaki Sai, Daiichi Sankyo, Co., Ltd., (Japan), +81-3-6225-1126 (office); Dr. Michaela Paudler-Debus, Daiichi Sankyo Europe GmbH, +49-(0)89-78-08-685 (office), +49-(0)172-845-8974 (mobile)