Full-dose versus low-dose rivaroxaban for superficial vein clots in the leg

A Pilot Randomized Double-Blinded Comparison of Full Treatment Dose Rivaroxaban for 90 Days to Prophylactic Dose Rivaroxaban for 45 Days in Patients With Lower Extremity Superficial Vein Thrombosis

This pilot will try full-dose rivaroxaban against the usual low dose (followed by placebo) in adults with superficial vein clots in the leg to see if the plan can recruit and run well.

Quick facts

• Phase: Phase2; Phase3
• Study type: Interventional
• Enrollment: 50 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Ottawa Hospital Research Institute (Academic / other)
• Locations: 2 sites (Ottawa, Ontario and 1 other locations)
• Trial ID: NCT06965998 on ClinicalTrials.gov

What this trial studies

This is a randomized pilot comparing therapeutic (full)‑dose rivaroxaban for 90 days to the common low (prophylactic) dose given for 45 days followed by 45 days of placebo in adults with ultrasound‑confirmed superficial vein thrombosis (SVT) of the lower limb. The trial enrolls adults diagnosed within 14 days and randomizes them to one of the two treatment strategies to test feasibility and study procedures. The primary operational question is the average monthly recruitment rate over a 12‑month period rather than definitive efficacy. Safety and signal outcomes will be monitored, but the study is not powered to prove superiority for clinical endpoints.

Who should consider this trial

Good fit: Adults (≥18) with a symptomatic, ultrasound‑confirmed superficial vein thrombosis of a lower extremity within 14 days who require anticoagulation and can provide informed consent are the ideal candidates.

Not a fit: Patients with other indications for anticoagulation, recent DVT/PE, high bleeding risk, need for antiplatelet therapy >100 mg aspirin, or on strong CYP3A4/P‑gp inhibitors are excluded and unlikely to receive benefit from participation.

Why it matters

Potential benefit: If successful, this approach could show whether full‑dose rivaroxaban better prevents progression to deep vein thrombosis or pulmonary embolism than the standard low dose and guide a larger definitive trial.

How similar studies have performed: Prior small trials and observational studies have suggested therapeutic anticoagulation may reduce SVT complications, but definitive randomized evidence is still limited.

Eligibility criteria

Inclusion Criteria:

1. Adult patients age ≥ 18 years old.
2. Objectively confirmed diagnosis within 14 days of an acute symptomatic SVT of the lower extremities by standardized CUS, where SVT is defined as incompressibility of a venous segment located along the course of a known superficial vein.
3. Anticoagulation for SVT is warranted per clinicians.
4. Able and willing to provide written informed consent.

Exclusion Criteria:

1. Other indication(s) for therapeutic or prophylactic dose anticoagulation (e.g. atrial fibrillation, mechanical valve, etc.).
2. History of PE or DVT within 6 months (180 days) of screening.
3. \>5 days of any anticoagulants for the index SVT.
4. Requires use of aspirin \>100mg daily or other antiplatelet agents.
5. Patients receiving concomitant systemic treatment with strong inhibitors of both CYP 3A4 and P-gp (e.g. cobicistat, ketoconazole, itraconazole, posaconazole, ritanovir, etc.).
6. Active bleeding or history of CRNMB or major bleeding (as defined by the ISTH) within 30 days of screening.
7. History of severe head trauma or ophthalmic, spinal, cerebral surgery within 90 days of screening.
8. Have acute endocarditis.
9. Thrombocytopenia (platelet count \<50,000/uL), acute hepatitis, chronic active hepatitis, cirrhosis with severe hepatic impairment defined by a Childs-Pugh class B or C.
10. Creatinine clearance \<30 ml/min.
11. Known contraindication to treatment with rivaroxaban.
12. Are participating in another interventional trial that would compromise the results or integrity of this trial as determined by the investigator.
13. Pregnant or breast feeding.
14. Known hereditary or acquired severe hemorrhagic disease.
15. Life expectancy \<3 months.
16. Unstable medical or psychological condition that would interfere with trial participation at the discretion of the site investigator.

Where this trial is running

Ottawa, Ontario and 1 other locations

• The Ottawa Hospital — Ottawa, Ontario, Canada (Recruiting)
• Hopital Montfort — Ottawa, Ontario, Canada (Not_yet_recruiting)

Study contacts

• Principal investigator: Tzu-Fei Wang, MD,MPH — Ottawa Hospital Research Institute
• Study coordinator: Tzu-Fei Wang, MD,MPH

Conditions SVT; Thrombosis; Superficial Vein Thrombosis; Pilot; Rivaroxaban; Feasibility; Full dose rivaroxaban; Treatment dose rivaroxaban