Inclusion Criteria1. Male between 18 to 50 years of age inclusive.
2. Either a non- or a light-smoker (<5 cigarettes per day) and agrees to refrain from smoking from the evening prior to first dosing until after the last PK sample of each step is drawn.
3. Body-mass index (BMI) of 18-32 kg/m2.
4. In good health on the basis of history, physical examination, and routine laboratory data.
5. Understands the procedures and agrees to participate in the study program by giving written informed consent.
6. Coagulation tests including aPTT, ECT, TT and PT within the reference range and a platelet count >145,000/mm3.
7. At screening, normal transaminases and negative Hemoccult Sensa(R) test. In the event of a positive Hemoccult test, the test should be repeated twice. If the results of both repeats tests are negative, the first Hemoccult test result is considered a false positive and the subject may be included.
Exclusion Criteria1. Mentally or legally incapacitated, significant emotional problems at the time of the study, or a history of psychiatric disorders within the last 10 years.
2. History within the last 10 years of asthma or other pulmonary disease, major cardiovascular, hepatic, endocrine (including diabetes), rheumatological, or renal disease or of prior spine or disc surgery.
3. History within the last 10 years of neurologic disease including stroke, transient ischemic attacks, seizure, head trauma, neurological tumors, brain or spinal cord surgery, neuropathy, or neuromuscular illness.
4. Active gastrointestinal disease including: peptic ulcer disease, gastritis, clinically significant Helicobacter pylori infection, inflammatory bowel disease, diverticular disease, colonic polyps, or of any gastrointestinal malignancy, or recent (within 3 weeks) benign enteritis.
5. History of any illness or condition that, in the opinion of the investigator, might confound the results of the study or pose additional risk in administering study drug to the subject (e.g., surgery within the previous 3 months).
6. Donated a unit of blood (450 mL) or participated in another clinical study drug trial within the 4 weeks prior to screening.
7. Family or personal history of bleeding disorders, including von Willebrand's disease.
8. History of significant gingivitis or other periodontal disease.
9. Received any prescription anticoagulant within the 30 days preceding screening including but not limited to warfarin, heparin, low-molecular weight heparin, hirulog, hirudin, argatroban, or dabigatran.
10. Has received 14 days prior to first dosing or anticipates needing during the study any prescription or nonprescription (including over the counter) preparation that contains aspirin (including low-dose aspirin), ibuprofen, indomethacin, diclofenac, naproxen, meloxicam, any other NSAID or NSAID-containing product such as pain relievers, cold or sinus remedies, or any other drug which influences platelet aggregation.
11. Received any investigational drug within the 30 days preceding screening.
12. Regular user of any medication (including over-the-counter medication) for 14 days prior to first dosing, except for acetaminophen. Subject currently uses prescription or nonprescription drugs on a regular basis which cannot be discontinued for 14 days prior to first dosing until the last study visit (including "recreational use" of illicit drugs). Subject has a recent history (within the last 2 years) of drug or alcohol abuse.
13. Subjects unable to stop using the following medications during the study (from first dosing until after the last study visit): erythromycin or erythromycin-like drugs, clarithromycin, diltiazem, cimetidine, warfarin-like anticoagulants, cyclosporine, itraconazole (or other systemic antifungal agents in the azole class), nefazodone, selective serotonin reuptake inhibitors (SSRI antidepressants), benzodiazepines, any systemic immunosuppressive agents (including glucocorticoids), cisapride and the H1 antagonists terfenadine and astemizole, and HIV protease inhibitors.
14. Unable to refrain from the use of antacids, H2 blockers, sucralfate, or proton pump inhibitors beginning 14 days prior to first dosing until the last study visit.
15. Has had major surgery within previous 3 months prior to first dosing or is anticipated to have major surgery within 2 weeks after completion of the study.
16. Positive hepatitis serology (HBsAg and anti-HCV) showing any sign of active hepatitis.
17. History of any chronic and/or active hepatic disease including hepatitis or biliary tract disease. Any subject with a history of hepatitis B or C at screening will be excluded. Subjects with a history of self-limited hepatitis A with complete resolutions documented at ≥12 months prior to entry would be eligible for inclusion.
18. HIV positive.
19. Significant unexplained and/or reproducible abnormalities on pre-study clinical examination or laboratory measurements.
20. History of significant drug allergy or any clinically significant adverse event of a serious nature related to the administration of either a marketed or investigational drug.
21. Known history of fainting from phlebotomy or from minor trauma resulting in bleeding.
22. Habitual heavy consumer of coffee (more than 6 cups of coffee/day).
23. Unable to refrain from consumption of grapefruit or grapefruit juice for at least 14 days prior to first dosing until the last study visit.
24. Unable to refrain from the use of St. Johns wort for at least 14 days prior to first dosing until the last study visit.