ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12610000806066

Ethics application status

Approved

Date submitted

17/09/2010

Date registered

27/09/2010

Date last updated

15/06/2011

Type of registration

Retrospectively registered

Titles & IDs

Public title

Enoxaparin compared to Warfarin for the treatment of calf vein blood clots

Scientific title

Randomised open label trial assessing the frequency of receiving therapeutic anticoagulant dosing in 6 weeks of enoxaparin treatment compared with 6 weeks of warfarin treatment, for treatment of symptomatic isolated calf vein thrombosis

Secondary ID [1]

Centre for Thrombotic and Bleeding Disorders Research Study Number: CTBR-009

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Calf Deep Vein Thrombosis

Condition category

Condition code

Blood

Clotting disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

At least 6 weeks with subcutaneous enoxaparin only, dosage 1.5mg/kg daily. Duration of treatment will be determined by the treating physician in accordance with American College of Chest Physicians (ACCP) and National Health and Medical Research Council (NHMRC) Guidelines with consideration of individual patient clinical profile and risk factors and the results of follow up ultrasound. Most patients will receive treatment for three months.

Intervention code [1]

Treatment: Drugs

Comparator / control treatment

Usual care: subcutaneous enoxaparin injections dosage 1.5mg/kg daily commenced immediately after diagnosis and commencing oral warfarin within a couple of days. Warfarin doses will be adjusted according to International Normalised Ratio (INR) blood tests. Once INR is in the range of 2.0 to 3.0 (usually 5 to 10 days) enoxaparin will be ceased and warfarin continues for at least 6 weeks. Warfarin dosage will be individualised for each patient and is expected to be within the range of 1mg-10mg per oral daily.
Duration of treatment will be determined by the treating physician in accordance with American College of Chest Physicians (ACCP) and National Health and Medical Research Council (NHMRC) Guidelines with consideration of individual patient clinical profile and risk factors and the results of follow up ultrasound. Most patients will receive treatment for three months.

Control group

Active

Outcomes

Primary outcome [1]

To show that the average time patients receive therapeutic warfarin dosing, is at least 25% lower than the average time patients treated with enoxaparin spend in therapeutic range. Time in therapeutic range for warfarin group will be calculated from INR results using Rosendaals' linear interpolation method. In the enoxaparin group therapeutic treatment will be measured by determining the number of missed doses of study drug as recorded in patient diaries and records of the number of pre-filled syringes used. An anti-factor Xa test will be conducted on day 14 (4 hours post injection time) to confirm that the treatment dose results in therapeutic anti-coagulation in that individual.

Timepoint [1]

Within the first six weeks of treatment

Secondary outcome [1]

To investigate patient expectations and satisfaction with enoxaparin compared with standard warfarin treatment using the PACT-Q (Perception of Anticoagulant Treatment Questionnaires).

Timepoint [1]

After the first six weeks of treatment

Secondary outcome [2]

To compare the cost of treating a calf Deep Vein Thrombosis (DVT) with enoxaparin than costs associated with warfarin including drug costs, laboratory costing and health care professional time. Resource utilization will be estimated by way of hospital records and patient diaries for both treatment groups. Resource data to be targeted will include doctor visits, drug costs and drug administration costs eg nurse visits, laboratory tests. Adverse reaction (e.g. recurrent Deep Vein Thrombosis (DVT) or Pulmonary Embolism (PE), bleeding event or post thrombotic syndrome) incidence and treatment costs will also be estimated. Hospital and government information sources will be accessed.

Timepoint [2]

Throughout the first six weeks of treatment

Secondary outcome [3]

To explore whether enoxaparin is as effective as warfarin in terms of clot resolution and bleeding events. A follow up ultrasound will be conducted at the week 6 visit unless symptomatic recurrence has occurred prior to 6 week visit. Recurrent VTE is defined as a thrombus in the contralateral leg, another deep vein of the same leg, or in the same venous system with a proximal extension of at least 5 cm above the original thrombus. Changes on ultrasounds from baseline will be rated by an independent blinded adjudicator. In addition patients will be asked to report any worsening signs or symptoms of Venous Thromboembolism (eg leg swelling or pain, shortness of breath etc.) up to 12 weeks after randomisation.

Timepoint [3]

During the first six weeks of treatment

Eligibility

Key inclusion criteria

Consenting adult patients with symptomatic isolated calf vein (infra-popliteal) DVT as demonstrated with a positive ultrasound.

Minimum age

18 Years

Maximum age

100 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

1. Pregnancy and breast feeding
2. Associated pulmonary embolism (PE) or proximal DVT
3. Known hypersensitivity to heparin
4. Thrombocytopenia (baseline platelets less than 50x10 9L)
5. Impaired renal function (baseline eGFR less than 30)
6. Presence of active bleeding or a pathology susceptible to bleeding in the presence of anticoagulant
7. Significant Liver Disease (baseline INR greater than 1.5)
8. Treatment with warfarin is contraindicated
9. Active malignancy
10. Inability or unwillingness of patients to complete English questionnaires or maintain a diary
11. Necessity to receive anticoagulants for an indication other than calf vein thrombosis

Study design

Purpose of the study

Treatment

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Other design features

Phase

Phase 4

Type of endpoint/s

Pharmacodynamics

Statistical methods / analysis

Recruitment

Recruitment status

Stopped early

Data analysis

Reason for early stopping/withdrawal

Date of first participant enrolment

Anticipated

18/06/2010

Actual

Date of last participant enrolment

Anticipated

Actual

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Recruitment postcode(s) [1]

2010

Recruitment postcode(s) [2]

2033

Recruitment postcode(s) [3]

2217

Funding & Sponsors

Funding source category [1]

Self funded/Unfunded

Name [1]

Address [1]

Country [1]

Primary sponsor type

University

Name

University of New South Wales

Address

UNSW
High St
Kensington
NSW
2033

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

St Vincent's Hospital Human Research Ethics Committee (HREC)

Ethics committee address [1]

De Lacy Building
St Vincent's Hospital
390 Victoria Street,
Darlinghurst NSW 2010

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

Approval date [1]

22/03/2010

Ethics approval number [1]

HREC/10/SVH/3

Summary

Brief summary

This trial is a research study into an alternative treatment for calf vein blood clots (Deep Vein Thrombosis).The purpose is to investigate whether treatment with Enoxaparin produces better outcomes than standard treatment with Warfarin. We will be looking at how much of the time patients are receiving optimal doses of each of the drugs (therapeutic dose), patient satisfaction with each of the treatments and the costs associated with each of the treatments. 

The patients who participate in this trial will be ‘randomised’ to receive either;
1. Warfarin treatment group: Patients receive tablets of Warfarin but you will also receive Enoxaparin (fine needle injections) for the first few days while their body adjusts to Warfarin. The dose of Warfarin needs to be customised for each patient. This is done with blood tests called INR tests every few days to start with and then once per week or once per fortnight depending how your body responds to the warfarin. This is standard treatment and will probably be managed by their general practitioner (GP).

2. Enoxaparin group: patients assigned to the Enoxaparin group will receive daily injections with a very fine needle into the skin of their abdomen or legs. Most patients will be able to learn to give themselves these injections. Alternatively we could teach a friend or relative to give them to the patient, or in some cases we may be able to provide someone to come to their house to give them the injections.

We think that treatment of symptomatic calf Deep Vein Thrombosis with enoxaparin may result in a higher chance of receiving therapeutic treatment (resulting from their being less variability in how patients bodies respond to be drug), a higher level patient satisfaction due to the decreased number of doctors visits, blood tests and dietary restrictions, and lower costs to the health care system than treatment with warfarin.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Address

Country

Phone

Fax

Contact person for public queries

Name

Dr Nicola Chapman

Address

St George Clinical School
Level 2, WR Pitney Clinical Sciences Building
St George Hospital
Gray St
Kogarah
NSW
2217

Country

Australia

Phone

+61 2 9113 2582

Fax

n.chapman@unsw.edu.au

Contact person for scientific queries

Name

Dr Nicola Chapman

Address

St George Clinical School
Level 2, WR Pitney Clinical Sciences Building
St George Hospital
Gray St
Kogarah
NSW
2217

Country

Australia

Phone

+61 2 9113 2582

Fax

n.chapman@unsw.edu.au

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

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