Multicentric RCT Comparing High Purity Type I Collagen-Skin Substitute vs dHACM in Treatment of Diabetic Foot Ulcers

The purpose of the present study is to compare the safety and efficacy of high-purity type-I collagen-based skin substitutes (HPTC), which are free from contaminants such as lipids, elastin, and other immunogenic particles, versus dehydrated human amnion/chorion membrane (dHACM) in the treatment of DFUs. This multicentric randomized, controlled clinical trial seeks to provide valuable insights into the best treatment strategy for enhancing healing outcomes and reducing the challenges posed by chronic DFUs.

Study will be carried out as a multicentric randomized, controlled open-label study to evaluate the safety and effectiveness of High Purity Type-I Collagen-based Skin Substitute (HPTC) compared to Dehydrated Human Amnion/Chorion Membrane (dHACM) for treating diabetic foot ulcers (DFUs). The trial will include patients with DFUs treated by wound care specialists at Adichunchanagiri Institute of Medical Sciences (AIMS), B. G. Nagara, Rajarajeswari Medical College and Hospital (RRMCH), Bangalore, JSS Medical College and Hospital (JSS), Mysore and Mysore Medical College and Research Institute (MMC&RI), Mysore, under the supervision of primary investigator Dr Naveen N. the other principal investigators include Dr Kamal Kumar M, Dr Ravi Shivaiah and Dr Vijay Kumar, respectively. Informed consent will be obtained from all participants prior to any study-related procedures at each of the 3 centres. Each patient will sign an Institutional Ethics Committee / Investigational Review Board (IEC/IRB)-approved consent form, at respective participating centres. IEC/IRB of Adichunchanagiri Institute of Medical Sciences, B. G. Nagara, will be the Designated Ethics Committee (DEC).

The study population will consist of patients seeking treatment for DFUs. Eligible patients will be those willing to participate and comply with scheduled visits on days 7, 10, 14, 17, 21, and 28. The study will include two phases: screening and treatment.

The screening phase aimed to determine patient eligibility for the treatment phase.

Centralized computer-generated block randomization, stratified by centre in a 1:1 ratio will be done. Due to the nature of the interventions, blinding of participants and clinicians is not feasible. However, outcome assessors and data analysts will be blinded to treatment allocation to minimize bias.

The treatment phase of the study will commence with a series of evaluations to ensure patients remained eligible. Participants who will continue to meet the inclusion criteria after the screening phase will be randomly assigned to one of two groups:

• Standard of Care (SOC) with High Purity Type-I Collagen-based Skin Substitute (HPTC).
• Standard of Care (SOC) with Dehydrated Human Amnion/Chorion Membrane (dHACM). Neither the patients nor the clinicians will be blinded to group assignments. The randomization will follow a balanced schedule, using permuted blocks of 12. When a patient will be ready for randomization, the study site will contact a representative from the sponsor, who will open a sequentially numbered opaque envelope to disclose the group assignment, maintaining allocation concealment.

Throughout the 4-week treatment phase, patients will be reassessed on days 7, 10, 14, 17, 21, and 28. The SOC dressing applied in both groups consisted of a three-layer system:

• First layer: Non-adherent, porous paraffin gauze.
• Second layer: Absorbent gauze pads.
• Third layer: Soft roll and Crepe bandage. If the study ulcer was found to be 100% re-epithelialized during the visit, no further study procedures will be conducted at that time. The patient will then be scheduled for a follow-up visit after one week to confirm the healing.

If full healing was not achieved, an evaluation will be carried out to check for any signs of clinical infection. If an infection is confirmed, treatment with topical antimicrobials or oral antibiotics will be permitted, though the use of topical antibiotics will be prohibited.

After this infection assessment, the ulcer would be cleaned, photographed, and debrided at the investigator's discretion to ensure a clean and granulating wound base with minimal adherent slough. The Standard of Care (SOC) will be then re-applied, and patients will be instructed to keep the bandage dry. Additionally, they will be advised to contact or return to the study site if the bandage became soiled or removed.

Study Completion Patients will complete the study 4 weeks after their initial treatment visit. However, if a patient's study ulcer healed before the 4-week period, they will be considered to have completed the study at the time of full healing.

Complete healing will be defined as 100% re-epithelialization of the ulcer with no drainage. Throughout the study, patients will retain the right to decline participation or withdraw at any time without prejudice.

In the event of a patient's withdrawal, their last recorded wound measurement will be carried forward to determine the change in wound size and calculate their final outcome.

Study Outcomes

Primary Endpoint:

• The primary outcome of the study will be the proportion of subjects who achieved improvement in wound healing, as observed on days 7, 10, 14, 17, 21, and 28. The wound closure of the target ulcer will be continuously monitored until the end of the 4-week period.

Secondary Endpoints:

• Vascular Incursion: To assess the infiltration of vascularity in the ulcer bed on day 5 post-treatment initiation (using HPE analysis by taking 2 mm diameter punch biopsy samples).
• Time to Achieve Complete Wound Closure: Time taken for the target ulcer to achieve complete wound closure will be assessed on days 7, 10, 14, 17, 21, and 28.
• Percentage Wound Area Reduction: This will be measured weekly on days 7, 10, 14, 17, 21, and 28 using digital photography.
• Mean Number of Repeated Applications of HPTC: The average number of times the reapplication of High Purity Type-I Collagen-based Skin Substitute (HPTC) to achieve wound closure will be documented as part of the study process.
• To monitor incidence of infection or complications
• To assess patient-reported quality of life
• To evaluate scar quality using validated scales (e.g., Vancouver Scar Scale)

Exploratory Endpoint:

• The appearance, structural stability, and fragility of the newly formed skin will be documented at each visit. Any recurrence of the wound will also be monitored.

Statistical Analysis

Data will be analysed on an intention-to-treat basis. Continuous variables will be summarized using means and standard deviations or medians and interquartile ranges, as appropriate. Categorical variables will be presented as frequencies and percentages. Comparative analyses will include:

• Descriptive statistics for baseline characteristics
• Chi-square tests for categorical outcomes.
• Independent t-tests or Mann-Whitney U tests for continuous outcomes.
• Kaplan-Meier survival analysis for time-to-event data, with log-rank tests to compare groups.

Multivariable regression models will adjust for potential confounders, such as baseline wound size and patient comorbidities.

Sample Size Calculation Based on previous studies, assuming a 20% difference in the primary outcome between groups, with 60% healing in the dHACM group and 80% in the HPTC group, a sample size of 60 participants per group (total N=60) combined from the 4 centres will provide 80% power to detect this difference at a 5% significance level, accounting for a 10% dropout rate.

Ethical Considerations The study will adhere to the Declaration of Helsinki principles and Good Clinical Practice guidelines. Ethical approval will be obtained from Institutional Ethics Committee of all participating centres. Informed consent will be obtained from all participants before enrolment. Adverse events will be monitored and reported. Participant confidentiality will be maintained, and data will be anonymized. Findings will be submitted to peer-reviewed journals and presented at relevant conferences.

Timeline Recruitment: 1 month Intervention & follow-up assessment: 3 months Data analysis and reporting: 1 month

Potential Implications This study aims to provide robust evidence on the comparative efficacy of HPTC and dHACM in managing DFUs. If HPTC proves superior to dHACM alone, it could establish a standard in treating DFUs, reducing healing time. Positive findings could influence clinical practice guidelines, offering alternative treatment options that may enhance patient outcomes and reduce healthcare costs.

Inclusion criteria

• Subjects must be at least 18 years of age or older.
• Subjects must have a diagnosis of type 1 or 2 Diabetes mellitus.
• At randomization subjects must have a target diabetic foot ulcer with a minimum surface area of 1.0 cm2 and a maximum surface area of 10.0 cm2 measured post debridement using a ruler to measure wound area.
• The target ulcer must have been present for a minimum of 4 weeks and a maximum of 52 weeks of standard of care prior to the initial screening visit.
• The target ulcer must be located on the foot with at least 50% of the ulcer below the malleolus.
• The target ulcer must be full thickness on the foot or ankle that does not probe to bone.
• Adequate circulation to the affected foot as documented by any of the following methods performed within 3 months of the first screening visit:

Transcutaneous Oxygen Measurement (TCOM) ≥30 mmHg Ankle-Brachial Index (ABI) between 0.7 and 1.3 Peripheral Vascular Resistance (PVR): Biphasic Toe-Brachial Index (TBI) ˃0.6 As an alternative, arterial Doppler ultrasound can be performed evaluating for biphasic dorsalis pedis and posterior tibial vessels at the level of the ankle of the target extremity.

• If the subject has two or more ulcers, they must be separated by at least 2 cm. The largest ulcer satisfying the inclusion and exclusion criteria will be designated as the target ulcer.
• The subject must consent to using the prescribed off-loading method for the duration of the study.
• The subject must agree to attend the twice-weekly/weekly study visits required by the protocol.
• The subject must be willing and able to participate in the informed consent process.
• Patients must have read and signed the IRB approved ICF before screening procedures are undertaken.

Exclusion criteria

• A subject known to have a life expectancy of <6 months.
• If the target ulcer is infected or if there is cellulitis in the surrounding skin.
• Presence of osteomyelitis or exposed bone, probes to bone or joint capsule on investigator's exam or radiographic evidence.
• A subject that has an infection in the target ulcer that requires systemic antibiotic therapy.
• A subject receiving immunosuppressants (including systemic corticosteroids at doses greater than 10 mg of Prednisone per day or equivalent) or cytotoxic chemotherapy.
• Topical application of steroids to the ulcer surface within one month of initial screening.
• A subject with a previous partial amputation on the affected foot is excluded if the resulting deformity impedes proper offloading of the target ulcer.
• A subject with a glycated hemoglobin (HbA1c) greater than or equal to 13% taken at or within 3 months of the initial screening visit.
• A subject with a serum creatinine ≥ 3.0mg/dL within 6 months of the initial screening visit.
• A subject with an acute Charcot foot, or an inactive Charcot foot, that impedes proper offloading of the target ulcer.
• Women who are pregnant or considering becoming pregnant within the next 6 months.
• A subject with end stage renal disease requiring dialysis.
• A subject who participated in a clinical trial involving treatment with an investigational product within the previous 30 days.
• A subject who, in the opinion of the Investigator, has a medical or psychological condition that may interfere with study assessments.
• A subject treated with hyperbaric oxygen therapy or a Cellular and/or Tissue Product (CTP) in the 30 days prior to the initial screening visit.