Wool-derived Keratin Dressings for Venous Leg Ulcers

Study Overview
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Brief Summary
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Venous leg ulcers (VLU) are the most common leg ulcer, can be painful, and limit work, lifestyles and activity, especially in older patients. Compression bandaging is the main treatment but there are few added treatments for patients with slow healing VLU. About 50% of patients with VLU may be slow healing. Research suggests using keratin dressings as well as using compression may help healing in patients with show healing VLU, but the current evidence is not enough to change clinical practice. The investigators will conduct a randomised controlled trial to test whether using keratin dressings is better than usual care for slow healing VLU.

Detailed Description
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A pragmatic, community based, single-blind, usual care-controlled, randomised trial to determine whether keratin dressings increase the proportion of patients with venous leg ulcers healed at 24 weeks when used in addition to compression in patients with slow healing venous leg ulcers. Participants in have compression therapy (system of choice guided by patient and/or clinical preference) as delivered through district nursing services at the study centres as a background treatment. Keratin dressings will be applied when the compression bandage is changed (approximately weekly). Usual care dressings will consist of the usual formulary of moist wound dressings available at each study centre. Participants will be district nursing service patients in five study centres in New Zealand with prevalent or incident venous leg ulcers. A venous leg ulcer will be defined as a wound on the lower leg that has remained unhealed for 4 or more weeks, appears to be primarily venous in aetiology with other causative diseases ruled out. If the participant has two or more venous leg ulcers, the largest ulcer will be the reference ulcer. A participant will be considered to have a slow healing venous leg ulcer if the ulcer area is larger than 5 cm2 and/or the ulcer has been present for more than six months. Participants will receive up to four visits from the research nurse - visit 1 to screen for eligibility, visit 2 to consent and randomise the participant, visits 3 and 4 to collect outcome data. District nurses will continue to visit the participant (about weekly or more frequently if required) to provide routine care between research nurse visits. Block randomisation will be used, stratified by study centre and prognostic index (ulcer size greater than 5cm2 and/or ulcer duration greater than 6 months) to ensure a balance of participants within study centres and for participants likely to be slow healers. Research nurses will input information on inclusion criteria, exclusion criteria, and relevant clinical history on consented participants via a tablet computer. The allocation will be generated after this information has been entered. Randomised participants will receive the allocated treatment until the reference ulcer heals or data collection is completed, whichever occurs sooner.

Official Title
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Keratin4VLU: A Randomised Controlled Trial of Wool-derived Keratin Dressings for Venous Leg Ulcers

Conditions
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Varicose Ulcer

Intervention / Treatment
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* Device: Keratin dressings
* Device: Usual care dressings


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical indications of venous leg ulceration Ankle Brachial Index ≥ 0.7 Able to tolerate compression therapy Ulcer area > 5cm2 and/or ulcer duration > 6 months Able to provide informed consent. Exclusion Criteria: Hypersensitivity to wool or wool alcohols Venous leg ulceration with exposed tendon or bone Infected venous leg ulcer at trial inception (eligible after infection resolved) Venous leg ulcer with critical bioburden at trial inception (eligible if resolved) History of rheumatoid arthritis or vasculitis Uncontrolled diabetes Severe liver, heart, or renal failure Severe peripheral arterial disease Suspected or diagnosed skin malignancy Other threat to safe participation.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Participants allocated to receive either keratin dressing or usual care dressing
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Keratin dressings<br>Wool-derived keratin matrix dressing applied with each change of the compression bandage until healing | Device: Keratin dressings<br>* Wool-derived keratin matrix dressings applied with each change of the compression bandage until healing or the trial ends<br>|
| Active Comparator: Usual care dressings<br>Dressing chosen from study centres' formulary of non-medicated moist wound dressings applied with each change of the compression bandage until healing | Device: Usual care dressings<br>* Dressings chosen from study centres' formulary of non-medicated moist wound dressings (non-adherent dressings, hydrogel, alginate, hydrofibre or polyurethane foam dressings) applied with each change of the compression bandage until healing or the trial ends<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of patients with complete healing of reference ulcer |  | 24 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Agreement between blinded and unblinded assessors on healing |  | 24 week outcome | 
| Time to complete healing of reference ulcer |  | Until data collection completed two years after first participant is recruited | 
| Change in estimated reference ulcer area | Estimated ulcer area will be derived measuring maximum width and length to determine area using formula for area of an ellipse. Such an approach is highly co-related (r=0.92) with more sophisticated measurement methods. | 24 weeks | 
| Change in health-related quality of life (generic) | The RAND-36 questionnaire will be used for measurement of generic health-related quality of life | 24 weeks | 
| Change in health-related quality of life (generic) | The EuroQuol-5D questionnaire will be used to generate utility values for cost-effectiveness modelling should that be undertaken | 24 weeks | 
| Change in health-related quality of life (disease-specific) | The Charing Cross Venous Ulcer Questionnaire will be used for measurement of disease-specific health-related quality of life | 24 weeks | 
| Incidence of adverse events |  | Until data collection completed two years after first participant is recruited | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Venous leg ulcer, Acellular skin substitutes, Keratin dressings