A Study to Evaluate the Relative Bioavailability and Intra-Subject Variability of Two Lots of E5501 40 mg Tablets Administered Twice as Single Oral Doses to Healthy Subjects

This is a randomized, open label, 4- way crossover, replicate design study to evaluate the bioavailability (BA) of E5501 new Phase 3 formulation Lot P97001ZZB 40 mg tablet manufactured July, 2009 (Treatment A ,reference drug) relative to Lot P01010ZZA 40 mg tablet manufactured January, 2010 (Treatment B, test drug) administered to 42 healthy male and female subjects.

Inclusion criteria

• Normal healthy adult male or female subjects age greater than or equal to 18 years and less than or equal to 55 years old.
• Body mass index greater than or equal to 18 kg/m2 and less than or equal to 32 kg/m2 at the time of screening.
• Platelet count between 120x109/L and 250x109/L.
• Women of childbearing potential must agree to use a double barrier method of contraception during the Randomization Phase of the study.

Exclusion criteria

• Evidence of clinically significant cardiovascular, hepatic, gastrointestinal, renal, respiratory, endocrine, hematologic, neurologic, or psychiatric disease or abnormalities or a known history of any gastrointestinal surgery that could impact the pharmacokinetics (PK)of the study drug.
• Agents associated with thrombotic events (including oral contraceptives) must be discontinued within 30 days of the first study drug administration.
• Evidence of organ dysfunction or any clinically significant deviation from normal in their medical history, e.g., history of splenectomy.
• History of venous or arterial thrombotic disease or other hypercoaguable state.
• Hemoglobin level less than 11.5 g/dL for females and 13.5g /dL for males