MEDIA RELEASE PR35400 
 
Analysis of Edoxaban Phase II Data Provides Insight Into Reduced Bleeding 
Events Seen in Once-Daily Dosing 
 
BOSTON and EDISON, N.J., July 15 /PRNewswire-AsiaNet/ -- 
 
          -- Pharmacokinetic Analysis of Atrial Fibrillation Study May 
 Explain Bleeding Rate Difference between Once-Daily and Twice-Daily Dosing 
         Regimens with Same Total Exposure of Factor Xa Inhibitor -- 
 
    A sub-analysis of a Phase IIb multinational study(1) with edoxaban(2) -- 
an investigational oral Factor Xa inhibitor - provides insights into why 
patients with non-valvular atrial fibrillation (AF) receiving edoxaban once 
daily (OD) experienced fewer bleeding events than patients given edoxaban 
twice a day (BID). The analysis finds that bleeding associated with edoxaban 
is most closely correlated with minimum concentration levels of the drug in 
the blood, and that these trough levels may best predict bleeding events, 
rather than total exposure or maximum concentration levels. 
 
    These findings were presented today at the XXII International Society on 
Thrombosis and Haemostasis Congress in Boston. Edoxaban is being developed 
solely by Daiichi Sankyo Company, Limited (TSE: 4568) as a potential 
treatment for the prevention of both arterial and venous thromboembolism; a 
Phase III trial is underway among patients with AF. 
 
    This pharmacokinetic (PK) analysis of the Phase IIb study examined the 
relationship between bleeding events reported in patients taking 30 or 60 mg 
edoxaban given either OD or BID and the concentration of edoxaban in their 
blood. The analysis examined overall bleeding rates when drug concentration 
levels reached the highest points (known as Cmax), lowest points (known as 
Cmin) as well as overall edoxaban exposure (measured by area under the curve 
or AUC). Delivering a compound twice per day generally allows for more 
consistent concentration levels in the blood. With twice-daily dosing, the 
Cmin levels (troughs) do not dip as low, and the Cmax levels (peaks) do not 
reach as high as when the compound is delivered once per day. 
 
    "When we assessed the pharmacokinetics in patients taking edoxaban once a 
day, lower minimum concentrations and fewer bleeding events were observed, 
compared to the same total daily dosage given twice a day," said Robert P. 
Giugliano, M.D., S.M., Associate Physician, Cardiovascular Division, Brigham 
and Women's Hospital. "These results countered our expectations that patients 
with higher maximum concentrations of edoxaban, in this case, those that 
received their total dose once daily, would have the most bleeding events. It 
may be that reaching lower Cmin levels with edoxaban once-a-day permits some 
degree of normal hemostasis to be temporarily reestablished, and that may be 
the reason why bleeding rates are lower with once-daily dosing." 
 
    "This Phase II study was a decisive study for Daiichi Sankyo in that it 
directed us to the optimal dosing regimen to study in our Phase III clinical 
trial ENGAGE AF-TIMI 48 - the more convenient 60 and 30 mg once-daily doses," 
said Francis Plat, M.D., vice president, clinical development at Daiichi 
Sankyo Pharma Development. 
 
    About the Phase IIb Safety Study 
    A total of 1,146 patients with AF with a CHADS2 index greater than or 
equal to 2 were enrolled in the initial Phase II study for three months. 
Patients were randomly assigned to receive either one of the four fixed dose 
regimens of edoxaban (30mg/N=235 or 60mg/N=234 administered once daily; 
30mg/N=244 or 60mg/N=180 administered twice daily), or warfarin (N=250) 
dose-adjusted locally to a target International Normalized Ratio (INR) of 
2.0-3.0 for 12 weeks. The INR was determined weekly for four weeks and every 
two weeks thereafter. Investigators, sponsors and study subjects were blinded 
to the edoxaban dose; however, those taking warfarin were aware they were 
randomized to the warfarin arm. 
 
    Bleeding events were evaluated using guidelines established by the 
International Society on Thrombosis and Haemostasis(3), the most sensitive 
scale of those currently used in clinical studies in cardiovascular disease. 
In the treatment groups receiving a once-daily dose of edoxaban, the lowest 
bleeding rates were observed in 17 patients (7.3 percent) in the 60 mg OD 
(N=234) and 13 patients (5.5 percent) in the 30 mg OD (N=235). In the 
treatment groups receiving a twice-daily dose of edoxaban, the highest 
bleeding rates were observed in 33 patients (18.3 percent) in the 60 mg BID 
(N=180) and 31 patients (12.7 percent) in the 30 mg BID (N=244). This 
sub-analysis examined only the population receiving edoxaban from the initial 
study. PK samples were taken before dosing and one to three hours post-dosing 
on day 28. The relationship between PK and all bleeding events was examined 
using logistical regression. 
 
    About Edoxaban 
    Edoxaban, the molecule originally referred to as DU-176b, is an oral 
anticoagulant that directly inhibits Factor Xa, a clotting factor in the 
blood. 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 test these compounds in 
humans. 
 
    Daiichi Sankyo is actively enrolling 16,500 patients in its pivotal Phase 
III trial for edoxaban in patients with atrial fibrillation. The Phase III 
study, Effective Anticoagulation with Factor Xa Next Generation in Atrial 
Fibrillation (ENGAGE-AF), is comparing edoxaban with warfarin (INR2-3) for 
the prevention of stroke and systemic embolic events (SEE) in patients with 
atrial fibrillation. Edoxaban is also being studied for treatment of VTE, and 
for the prevention of DVT after major orthopaedic surgery. 
 
    About Daiichi Sankyo 
    A global pharmaceutical innovator, Daiichi Sankyo Co., Ltd., was 
established in 2005 through the merger of two leading Japanese pharmaceutical 
companies. This integration created a more robust organization that allows 
for continuous development of novel drugs that enrich the quality of life for 
patients around the world. A central focus of Daiichi Sankyo research and 
development are thrombotic disorders, malignant neoplasm, diabetes mellitus, 
and autoimmune disorders. Equally important to the company are hypertension, 
hyperlipidemia or atherosclerosis and bacterial infections. 
 
    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 
whatsoever to update these forward-looking statements or to conform them to 
future events or developments. 
 
    (1) "Randomized, Parallel Group, Multicenter, Multinational Study 
Evaluating Safety of DU-176b Compared with Warfarin in Subjects with 
Non-Valvular Atrial Fibrillation," presented at American Society of 
Hematology annual meeting in December 2008. 
 
    (2) Edoxaban tosylate is also known as DU-176b. 
 
    (3) Schulman S., et al. Definition of major bleeding in clinical 
investigations of antihemostatic medicinal products in non-surgical patients. 
Journal of Thrombosis and Haemostasis 2005;3: 692-694. 
 
    SOURCE:  Daiichi Sankyo, Inc. 
 
    CONTACT: Toshiaki Sai, Daiichi Sankyo Co., Ltd (Tokyo) 
             +81-3-6225-1126; 
 
          or Kimberly Wix, Daiichi Sankyo, Inc. (US) 
             +1-973-944-2338 
             Mobile: +1-908-656-5447;  
 
          or Dr. Michaela Paudler-Debus, Daiichi Sankyo Europe, 
             +49-(0)89-7808-685 
             Mobile: + 49-(0)172-845-8974 
 
 
 
 
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