Safety and Efficacy of Therapeutic Anticoagulation With Tinzaparin During Pregnancy Via Weight-based Dosing

Overview

The purpose of this study is to evaluate the safety and efficacy of therapeutic anticoagulation with tinzaparin during pregnancy via weight-based dosing.

Full Title of Study: “Weight-Adjusted Dosing of Tinzaparin in Pregnancy”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Masking: None (Open Label)
  • Study Primary Completion Date: October 2010

Detailed Description

Physicians in the Calgary Health Region are using tinzaparin (predominantly) and other low molecular weight heparins (LMWHs) for the treatment venous thromboembolism (VTE) in pregnancy. The most recent anticoagulation guidelines from American College of Chest Physicians (ACCP) suggest that heparin levels (anti-Factor-Xa activity levels) may be done periodically through pregnancy to determine the need to adjust the dose of LMWH as pregnancy progresses. This monitoring is widely practiced. There is no clear consensus in the literature, however, with some experts suggesting that initial and subsequent dosing may be done based on weight alone (as is done in the non-pregnant population). Given the multiple physiologic changes which occur to drug metabolism during pregnancy, this bears further evaluation. To date, there is very limited data on weight-adjusted dosing of LMWH in pregnancy. This study is therefore designed to determine if dosing of tinzaparin during pregnancy based on weight, with periodic weight-based adjustments, will result in adequate therapeutic anticoagulation.

Interventions

  • Drug: Tinzaparin
    • LMWH (tinzaparin-Innohep, Leo Pharma A/S) 175 anti-factor Xa units per kilogram of body weight sub-cutaneously once daily. Treatment will be done for the duration of the pregnancy.

Arms, Groups and Cohorts

  • Experimental: A
    • Women requiring therapeutic anticoagulation, singleton pregnancy,<30weeks

Clinical Trial Outcome Measures

Primary Measures

  • Rate of anti-Xa levels falling outside the target range of 0.4-1.2IU/mL
    • Time Frame: anti-Xa level Day 1,28, then q4 weeks

Secondary Measures

  • mean dosage requirement in each trimester
    • Time Frame: 1 year
  • rate of clinical outcomes (PE/DVT) – objective testing of DVT/PE from radiology
    • Time Frame: 1 year

Participating in This Clinical Trial

Inclusion Criteria

  • Singleton pregnancies in women over the age of 18 requiring anticoagulation for acute VTE (DVT/PE), or high-risk prophylaxis at a tinzaparin dose of 175 IU/kg. – High-risk patients include those with multiple (two or more) episodes of VTE and/or women receiving long-term anticoagulants (e.g. single event with known thrombophilia; APLAs and history of venous thrombosis) Exclusion Criteria:

  • Multiple gestation – Prosthetic valves – Active bleeding or other contraindication to anticoagulation therapy – Allergy to heparin, bisulfites, or fish, history of HIT (heparin induced thrombocytopenia), severe hypertension (diastolic >130) – Severe hepatic or renal failure – Patients over 100kg.

Gender Eligibility: Female

Minimum Age: 18 Years

Maximum Age: 45 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of Calgary
  • Collaborator
    • LEO Pharma
  • Provider of Information About this Clinical Study
    • Principal Investigator: Dr. Sue Ross, Adjunct Professor – University of Calgary
  • Overall Official(s)
    • Paul Gibson, M.D. FRCPC, Principal Investigator, University of Calgary
    • Kendra Newell, M.D., Study Chair, University of Calgary
    • David Sam, M.D. FRCPC, Study Chair, University of Calgary

Citations Reporting on Results

Gibson PS, Newell K, Sam DX, Mansoor A, Jiang X, Tang S, Ross S. Weight-adjusted dosing of tinzaparin in pregnancy. Thromb Res. 2013 Feb;131(2):e71-5. doi: 10.1016/j.thromres.2012.11.018. Epub 2012 Dec 13.

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