Daiichi Sankyo Completes Enrollment of the Edoxaban Global Phase III ENGAGE AF-TIMI 48 Study in Patients With Atrial Fibrillation

More Than 21,000 Patients Enrolled in the Largest Clinical Study With a Factor Xa Inhibitor

LONDON, December 1, 2010 - Daiichi Sankyo Company, Limited (TSE: 4568), announced today that it has
successfully completed patient enrollment for its phase III ENGAGE AF-TIMI 48
clinical study of edoxaban, a direct, specific, oral Factor Xa inhibitor that
is being investigated in two different dosing regimens given once-daily, to
prevent the occurrence of strokes and systemic embolic events (SEE) in
patients with atrial fibrillation (AF).

An estimated 4.5 million people in Europe, 2.2 million Americans, and
more than 800,000 people in Japan suffer from AF.[i],[ii],[iii] Due to the
aging population, the number of patients with AF worldwide is likely to
increase 2.5 fold by the year 2050.[iv]

The ENGAGE AF-TIMI 48 study began enrollment in November 2008. It is an
event-driven, randomised, double-blind, double-dummy, parallel group,
multi-centre, multi-national study designed to assess the efficacy and safety
of edoxaban compared to the current standard of care, warfarin. Patients in
the study are randomised to one of three treatment groups: 30 mg edoxaban
once-daily, 60 mg edoxaban once-daily, or warfarin, a vitamin K antagonist
treatment. In addition, edoxaban doses are further adjusted to treat patients
with renal impairment and/or low body weight, or those taking strong
P-glycoprotein inhibitors. Those randomised to warfarin are dosed once-daily
to achieve an International Normalised Ratio (INR) between 2.0 and 3.0.

"The completion of enrollment for the largest AF outcomes study ever
undertaken — ENGAGE AF-TIMI 48 — marks a key milestone in the development
of edoxaban and for Daiichi Sankyo," said Glenn Gormley, MD, PhD, Chief
Science Officer & President, Daiichi Sankyo Pharma Development.

This phase III global AF study, Effective aNticoaGulation with factor xA
next GEneration in Atrial Fibrillation (ENGAGE AF-TIMI 48), enrolled 21,107
subjects at nearly 1,400 clinical trial sites located throughout North
America, South America, Africa, Asia, Europe and Australia/New Zealand. The
primary endpoint of this study is to compare the efficacy of edoxaban to
warfarin in the prevention of stroke and SEE. The primary safety assessment
is the incidence of major and clinically relevant non-major bleeding events.

"As new options to prevent stroke in AF patients become available, it
will be important that these treatments eliminate the need for extensive
monitoring and dietary modifications as well as deliver a balanced benefit to
risk profile," said Elliott Antman, MD, Professor of Medicine, Harvard
Medical School, Director, Samuel A. Levine Cardiac Unit, Cardiovascular
Division, Brigham and Women's Hospital and Senior Investigator, TIMI Study
Group, Global Principal Investigator, ENGAGE AF-TIMI 48. "Based on phase II
study results, edoxaban has shown promise of potentially addressing the needs
of patients with AF and the physicians caring for them to minimise the risk
of embolic events."

About Atrial Fibrillation

Atrial fibrillation (AF) is an irregular heartbeat that is caused when
the upper chambers of the heart (the atria) do not beat regularly and instead
quiver erratically. When this happens, blood may stagnate in the atria
leading to blood clots. These blood clots can break off and travel through
the blood stream to the brain where they can plug the blood vessels, causing
a stroke. AF is the most common type of clinically significant arrhythmia.[v]

Patients with AF have five times higher risk of having a stroke than
individuals without AF.[vi] These patients also tend to have more serious
first strokes than patients without AF, resulting in higher mortality rates
and longer hospital stays.[vii]

About Edoxaban

Edoxaban is a once-daily oral anticoagulant that directly inhibits Factor
Xa, an important factor in the coagulation process. Edoxaban may offer
physicians a wide therapeutic window to help address patients' unique needs.
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.

Daiichi Sankyo Europe, headquartered in Munich, Germany, is a member of
the Daiichi Sankyo Group. For more information on Daiichi Sankyo Europe,
please visit www.daiichi-sankyo.eu.

For more information, please contact:

Forward-Looking Statements

This news release may contain forward-looking statements based on current
assumptions and forecasts made by Daiichi Sankyo group. Various known and
unknown risks, uncertainties and other factors could lead to material
differences between the actual future results, financial situation,
development or performance of the company and the estimates given here. These
factors include those discussed in our public reports, which are available on
the website at www.daiichisankyo-us.com. The company assumes no
liability whatsoever to update these forward-looking statements or to conform
them to future events or developments.

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[i] Fuster V et al. "ACC/AHA/ESC 2006 Guidelines for the Management of
Patients with Atrial Fibrillation - Executive Summary," Circulation. 2006;
114:700-752.

[ii] American Heart Association. "Atrial Fibrillation,"
www.americanheart.org/presenter.jhtml?identifier=4451. Last accessed
November 24, 2010.

[iii] Inoue H et al. "Prevalence of Atrial Fibrillation in the General
Population of Japan: An Analysis Based on Periodic Health Examination
International," International Journal of Cardiology. 2009; 137:102-107.

[iv] Santini M, Ricci RP. "The Worldwide Social Burden of Atrial
Fibrillation: What Should Be Done and Where Do We Go," Journal of
Interventional Cardiac Electrophysiology. 2006; 17:183-188.

[v] National Heart Lung and Blood Institute. "What is Atrial
Fibrillation," www.nhlbi.nih.gov/health/dci/Diseases/af/af_what.html.
Last accessed November 24, 2010.

[vi] Hylek HM et al. "Effect of Intensity of Oral Anticoagulation on
Stroke Severity and Mortality in Atrial Fibrillation,"
The New England Journal of Medicine. 2003; 349:1019-1026.

[vii] Jorgensen HS et al. "Acute Stroke with Atrial Fibrillation,"
Stroke. 1996; 27:1765-1769.

    Toshiaki Sai
    Daiichi Sankyo Co., Ltd (Tokyo)
    Phone: +81-3-6225-1126

    Kimberly Wix
    Daiichi Sankyo, Inc. (US)
    Phone: +1-973-944-2338
    Mobile: +1-908-656-5447

    Dr. Michaela Paudler-Debus
    Daiichi Sankyo Europe
    Phone: +49-(0)89-7808-685
    Mobile: +49-(0)172-845-8974

Toshiaki Sai, Daiichi Sankyo Co., Ltd (Tokyo), Phone: +81-3-6225-1126; Kimberly Wix, Daiichi Sankyo, Inc. (US), Phone: +1-973-944-2338, Mobile: +1-908-656-5447; Dr. Michaela Paudler-Debus, Daiichi Sankyo Europe, Phone: +49-(0)89-7808-685, Mobile: +49-(0)172-845-8974