A Randomized, Controlled Clinical Trial Evaluating the Efficacy of Type-I Collagen-based Skin Substitute vs. Dehydrated Human Amnion/Chorion Membrane in the Treatment of Venous Leg Ulcers
Phase: NA
Conditions: Venous Leg Ulcers
Sponsor: Dr Naveen Narayan MS, MCh (Plastic Surgery)

 
Title: A RCT Evaluating Efficacy of Type-I Collagen Skin Substitute vs. 
Human Amnion Membrane in Treatment of Venous Leg Ulcers 
 
NCT No: NCT06831760 
 
Date: July 8, 2025 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Introduction: 
Venous leg ulcers (VLUs) are the most common type of chronic lower extremity ulcerations, 
accounting for 60-80% of all leg ulcers [1]. They affect approximately 0.18% to 1.35% of the 
general population and impose a substantial economic burden on healthcare systems 
worldwide [2]. Chronic venous insufficiency leads to sustained hypertension in the venous 
system, resulting in capillary damage and impaired healing [3]. These ulcers present a 
significant public health challenge, leading to impaired quality of life, substantial healthcare 
expenditures, and recurrence rates exceeding 70% [4]. Standard treatments include 
compression therapy and conventional wound dressings; however, healing rates remain 
suboptimal, often resulting in prolonged healing times and high recurrence rates [5] 
The pathophysiology of venous leg ulcers involves complex interactions between venous 
hypertension, inflammatory processes, and impaired cellular function within the wound 
environment. [6] Chronic venous insufficiency leads to increased hydrostatic pressure, 
capillary leakage, and tissue hypoxia, creating a hostile microenvironment that impedes 
normal wound healing processes. [7, 8]. The presence of elevated matrix metalloproteinases, 
chronic inflammation, and bacterial colonization further contributes to delayed healing and 
wound chronicity. [9] 
Wound healing is a complex biological process involving phases of inflammation, 
proliferation, and remodelling. Traditional wound care often fails to adequately stimulate this 
cascade in chronic wounds, necessitating the use of advanced biologic dressings. [10] 
Recent advances in wound care have led to the development of bioengineered skin substitutes 
designed to address the underlying molecular and cellular deficits in chronic wounds. [11] 
Advanced wound care options such as collagen-based dressings and allografts have been 
developed to enhance the wound healing microenvironment. Among these, Type-I collagen-
based skin substitutes (HPTC) (such as Helicoll®) and dehydrated human amnion/chorion 
membrane (dHACM) have gained prominence [12-15]. 
HPTC is a high purity Type-I collagen matrix derived from bovine tendon and processed to 
preserve native triple-helix structure, providing a biocompatible scaffold for cellular ingrowth  
and promote angiogenesis [16]. dHACM comprises preserved amniotic tissue layers, rich in 
cytokines and growth factors, and extracellular matrix components that theoretically promote 
wound healing through regenerative mechanisms. Clinical studies have demonstrated the 
efficacy of dHCAM in various chronic wound types [17].  

Recent systematic reviews indicate that bioengineered skin substitutes may improve healing 
outcomes in venous leg ulcers, with healing probabilities ranging from 0.11 to 0.65 over 
variable time periods. Clinical trials with dHACM have demonstrated healing rates of 75% at 
12 weeks in venous leg ulcers [18-20]. 
Prior studies in diabetic foot ulcers have reported promising results using HPTC compared to 
dHACM [21, 22]. While numerous studies have evaluated treatments individually, direct 
comparative studies evaluating their relative efficacy in venous leg ulcer management is null. 
The present study aims to bridge this gap by conducting a randomized, controlled clinical 
trial comparing the efficacy of HPTC and dHACM in terms of healing efficacy and patient-
reported outcomes. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Materials and Methods: 
This single-centre, prospective, randomized, open label, single-blinded, controlled, parallel-
group clinical trial was conducted at a tertiary care centre over a 6-month period. The study 
protocol was reviewed and approved by the Adichunchanagiri Institute of Medical Sciences 
Institutional Ethics Committee with approval number AIMS/IEC/004/2025 and conducted in 
accordance with the Declaration of Helsinki. All participants provided written informed 
consent before enrolment. Additionally, all study products used in this study were 
manufactured, handled, and stored in accordance with applicable Good Manufacturing 
Practices. The study was registered in Clinical Trials.gov with identity number 
NCT06831760. Confidentiality was maintained with all patient records. 
Sixty patients aged 18–80 years with non-infected chronic venous ulcers of more than 4 
weeks' duration, measuring between 2 cm2 and 25 cm2, with adequate arterial inflow (Ankle 
Brachial Index > 0.8) and willingness to comply with follow-up were included. Exclusion 
criteria included active infection requiring systemic antibiotics, uncontrolled diabetes, 
peripheral arterial disease, autoimmune disorders, malignancy, immunosuppression, 
pregnancy and known allergies to bovine or human-derived products. Patients were randomly 
allocated into two equal groups using a computer-generated sequence: 
 
Group A: Treated with High Purity Type-1 collagen-based skin substitute (HPTC) 
(n=30) 
 
Group B: Treated with dHACM (n=30) 
Intervention: Application protocols followed manufacturer instructions. Wounds were 
debrided before initial grafting. All patients received standard wound cleaning and 
compression therapy. In addition: 
 
Group A received application of HPTC, a high-purity Type-I collagen dressing. The 
product was sized to cover the entire wound surface with a 1-cm margin and secured 
with appropriate secondary dressings  
 
Group B received dHACM graft. The membrane was rehydrated and applied to cover 
the wound bed completely 
 
Standard Wound Care for Both Groups - First layer of a non-adherent and porous 
paraffin gauze followed by Second layer of absorbent gauze pads and then third layer 
of a soft roll and crepe bandage. 
Infection control measures were taken and patient education regarding wound care and leg 
elevation were given. Repeat application was done if deemed necessary.  

Outcome Measures: 
Primary Outcome Measure:  
i. 
Percentage wound area reduction - percentage wound area reduction from week 1 
through week 6 plus 1 week follow up measured manually with digital photography 
Secondary Outcome Measure:  
i. 
Infiltration of vascularity in the ulcer bed - Infiltration of vascularity in the ulcer 
bed on day 5 of application. Vascularity assessment will be done using biopsy on Day 
0 of application to be compared with Day 5 after application of Type-I Collagen-
based Skin Substitute or Human Amnion/Chorion Membrane. [Time Frame: 6 days].  
Histopathological Assessment – Before application and on the 5th day post-
application of either HPTC or dHCAM, a 2mm punch biopsy was obtained from the 
wound edge extending into the wound bed under local anaesthesia (2% lidocaine 
without epinephrine). Biopsy samples were immediately fixed in 10% neutral 
buffered formalin for 24 hours, processed through graded alcohols, and embedded in 
paraffin blocks. Serial sections of 4μm thickness were prepared and stained with: 
i. 
Hematoxylin and Eosin (H&E) for general morphology 
ii. 
Masson's Trichrome for collagen assessment 
iii. 
CD31 immunohistochemistry for capillary density evaluation 
iv. 
α-SMA immunohistochemistry for fibroblast activity 
Histological Parameters Evaluated 
1. Vascular Infiltration: Assessed by counting new blood vessels per High Power Field 
(hpf) (0-3 scale) 
 0: Minimal vascular ingrowth (<5 vessels/hpf) 
 1: Mild infiltration (5-10 vessels/hpf) 
 2: Moderate infiltration (11-20 vessels/hpf) 
 3: Abundant infiltration (>20 vessels/hpf) 
2. Neo-epithelialization: Measured as epithelial migration distance from wound edge 
(0-3 scale) 
 0: No epithelial migration 
 1: Minimal migration (<25% wound coverage) 
 2: Moderate migration (25-75% coverage) 
 3: Extensive migration (>75% coverage) 

3. Fibroblast Activity: Quantified by counting α-SMA positive fibroblasts per HPF and 
assessment of fibroblast morphology (0-3 scale) 
 0: Sparse, inactive fibroblasts 
 1: Moderate cellularity, minimal matrix production 
 2: High cellularity, active-matrix synthesis 
 3: Very high activity with extensive matrix deposition 
4. Capillary Density: Evaluated using CD31 staining, counted as vessels per mm² of 
tissue 
5. Inflammatory Response: Graded semi-quantitatively (0-3 scale) 
 0: Minimal inflammatory infiltrate 
 1: Mild chronic inflammation 
 2: Moderate mixed inflammation 
 3: Severe acute inflammation 
6. Collagen Deposition: Assessed using Masson's Trichrome staining (0-3 scale) 
 0: Minimal collagen matrix 
 1: Loose, immature collagen 
 2: Moderate organized collagen 
 3: Dense, mature collagen architecture 
All histological assessments were performed by two independent pathologists blinded to 
treatment allocation. Inter-observer agreement was assessed using Cohen's kappa coefficient. 
 
ii. 
Time to achieve complete wound closure - the time to achieve complete wound 
closure (defined as 100% epithelialization with no drainage) of the target ulcer by the 
end of 6 weeks [Time Frame: 6 weeks] 
iii. 
Proportion of subjects to obtain complete closure - the proportion of subjects that 
obtain complete closure over the 6-week treatment period [Time Frame: 6 Weeks] 
iv. 
Mean number of repeated application - mean number of repeated applications of the 
Advanced Skin Substitute & Human Amnion/Chorion Membrane used to obtain 
wound closure [Time Frame: 6 Weeks] 
v. 
Incidence of adverse events - incidence of adverse events related to the intervention 
(e.g., infection, allergic reactions) [Time Frame: 6 Weeks] 
 
 

Other Pre-specified Outcome Measures: 
i. 
Change in Pain - change in pain measured by a Visual Analog Scale with score range 
from 0 to 10, wherein 0="no pain" to 10="severe pain" [Time Frame: 7 weeks 
including 1-week follow-up]. Pain scores were assessed weekly. 
ii. 
Change in quality of life - change in quality of life assessed using the Wound-QoL 
questionnaire measured as 'not at all', 'a little', 'moderately', 'quite a lot' and 'very 
much' for 17 questions [Time Frame: 7 weeks including 1-week follow-up] 
iii. 
Healed Wound appearance assessment using Manchester Scar Scale - the resultant 
new skin is assessed and documented at each visit using the Manchester Scar Scale 
assessing colour, finish, contour, distortion & texture with values given from 1 to 4 
wherein 1 denotes excellent and 4 means poor [Time Frame: 7 weeks including 1-
week follow-up] 
 
Data Collection and Monitoring 
a. Baseline data: Demographics, medical history, ulcer characteristics. 
b. Weekly follow-ups: Wound measurements (photographic documentation), assess 
healing progress, pain scores, record adverse events and patient-reported outcomes. 
c. Histopathological specimens were obtained at baseline and day 5 for vascularity 
assessment. 
d. End-of-Study Visit (Week 6): final wound assessment, collect patient feedback on 
treatment experience, quality of life and scar assessment. 
e. Data entry and monitoring was managed using an electronic data capture system.