The purpose of this study is to determine the optimal dose of BAY 59-7939 and to compare the safety and effectiveness of this new drug with the standard way of treatment of deep vein thrombosis (heparin infusion plus one of the vitamin K antagonists), taking into account new events of thrombosis and pulmonary embolism and bleeding risk.

Within the U.S., Johnson & Johnson is sponsor.

Inclusion Criteria:

• Confirmed acute symptomatic DVT, i.e. proximal or extensive calf-vein thrombosis involving at least the upper third part of the calf veins, without concomitant symptomatic PE
• Written informed consent

Exclusion Criteria:

• Legal lower age limitations (country specific)
• Thrombectomy, insertion of a caval filter, or use of a fibrinolytic agent to treat the current episode of DVT
• Other indication for VKA than PE/DVT
• More than 36 hours pre-randomization treatment with therapeutic dosages of (LMW) heparin or more than a single dose of VKA prior to randomization
• Participation in another pharmacotherapeutic study within the prior 30 days
• Creatinine clearance < 30 mL/min, impaired liver function (transaminases > 2 x ULN), or bacterial endocarditis
• Life expectancy < 3 months
• Active bleeding or high risk for bleeding contraindicating treatment with (LMW) heparin
• Uncontrolled hypertension: systolic blood pressure > 200 mmHg and diastolic blood pressure > 110 mmHg
• Pregnancy or childbearing potential without proper contraceptive measures
• Any other contraindication listed in the labeling of warfarin, acenocoumarol, phenprocoumon, fluindione, UFH, enoxaparin, or tinzaparin
• Systemic treatment with azole compounds or other strong CYP3A4 inhibitors (e.g. ketoconazole, fluconazol, itraconazole, HIV protease inhibitors) within 4 days prior to randomization and during the study