Simplifying Complex Wound Care With Innovative Medical Technologies
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Current standard-of-care procedures used to treat complex and chronic wounds are often highly invasive, with low efficiencies and high complication rates. To address the significant unmet medical needs in chronic wound treatment, PolarityTE is developing a range of regenerative tissue products utilizing a patient’s own cells and tissues, such as SkinTE®.
Technology Networks recently spoke with Richard Hague, PolarityTE’s chief executive officer and president, to learn more about the science behind SkinTE and how it could overcome some of the limitations associated with other chronic wound treatments. In this interview, Richard also discusses what he envisions for the future of the wound care space.
Anna MacDonald (AM): What are the main causes of diabetic foot ulcers (DFU) and other complex wounds, and what are the consequences of leaving these conditions untreated?
Richard Hague (RH): Diabetic foot ulcers are a common complication of living with diabetes. An estimated 1 to 3.5 million people in the United States have a history of a diabetic foot ulcer with a new diagnosis of diabetic foot ulcer occurring every 1.2 seconds globally.
A diabetic foot ulcer is an open sore or wound on the foot of a person with diabetes. Diabetic foot ulcers form from vertical and shear stress in patients who suffer from peripheral neuropathy, or nerve damage, and lower extremity ischemia, or lack of blood flow. Shear is a major cause of skin breakdown and occurs from a combination of downward pressure and friction whereas vertical stress occurs through repetitive compression.
Infection may also occur if the diabetic foot ulcer is not properly and frequently attended to. Bacteria can enter the bloodstream through the open wound and may cause sepsis, a life-threatening complication of infection that results in inflammation throughout the body; or osteomyelitis, a bone infection. Ulcer reoccurrence is a significant issue, and 40% of patients with diabetic foot ulcers experience ulcer reoccurrence at 1 year. This percentage increases at 5 years with 65% of diabetic foot ulcer patients experiencing ulcer reoccurrence.
The widespread occurrence of diabetic foot ulcers and other risks also raises concern for two of the most feared outcomes for patients who experience this condition: amputation and an increased mortality rate. Amputations occur when other treatment options have been exhausted by health care professionals and the wound is unable to heal or continues to grow. The mortality rate after diabetes-related amputation is greater than 70% at 5 years for patients.
Pressure injuries are localized damage to the skin and underlying tissue of the body and are a result of pressure in combination with moisture and shear. Pressure injuries develop when pressure cuts off blood circulation to the skin for multiple hours or days at a time, the affected area is in the same position for an extended period, or fluids cause the skin to become overly moist. These often occur when a patient is bed-ridden, hospitalized for many weeks or months, inactive, or immobile.
Similar to diabetic foot ulcers, pressure wounds have long-term complications including a variety of infections throughout the body. If the site of the wound becomes infected, the infection can spread to different areas of the body such as the skin, bone, blood, brain and spinal cord, and heart. Pressure wounds can lead to long-term skin and tissue damage.
AM: Can you describe the current standard-of-care procedures for complex wound care? What are the problems complex wounds and pressure/trauma injuries place on doctors, nurses, and first-responders?
RH: Health care professionals utilize two classification systems to identify the stage of diabetic foot ulcers and pressure injuries. The Wagner Ulcer Classification System utilizes a scale from 0 to 5, 5 being the most extreme with extensive gangrene in the foot. The National Pressure Injury Advisory Panel (NPIAP) and the European Pressure Ulcer Advisory Panel (EPUAP) Guidelines classify pressure injuries numerically from I to IV by the depth of wound through inspection and palpation. The most severe form of pressure injury, categorized by Stage IV, extends through the deep fascia skin layer and exposes muscle, tendon, ligament, cartilage or bone.
Physicians will recommend a treatment plan based on the severity of the wound as categorized by the appropriate classification system. For both complex wounds and diabetic foot ulcers, offloading and debridement are the main methods of wound care. Offloading refers to the minimization or removal of weight and pressure on the foot to help wounds heal. Debridement involves thoroughly cleaning the wound and removing dead or infected skin tissue.
Additional treatment methods are used in tandem with offloading and debridement and include off-the-shelf allogeneic or xenogeneic products. These off-the-shelf products are used to speed up contracture which leads to the formation of scar tissue. Early surgical closure of pressure injuries is also a treatment option commonly used by physicians.
AM: What are some of the main limitations associated with conventional approaches to treating DFU and other hard-to-treat wounds?
RH: There is a significant unmet need to develop innovative products for complex wounds that are more efficient and economical for patients and doctors, with fewer complications and better results. Traditional methods to heal other wounds like skin grafting are rarely used due to the poor blood flow in the wound and the need for robust tissue.
The main limitations of conventional approaches to complex wounds involve difficulty in the application of the product or execution of the procedure along with efficacy. Off-the-shelf allogeneic or xenogeneic products require multiple applications, leading to frequent visits to clinical care settings for patients and multiple appointments for physicians. These types of treatments also pose a risk of rejection where the body recognizes implanted tissue as foreign, resulting in infections and low closure rates.
Both allogeneic and xenogeneic products have been studied primarily in superficial ulcers. However, a larger problem exists in the treatment of more advanced stage wounds (Wagner 2 and above). Treatments for full-thickness ulcers that extend through several layers of skin and sometimes muscle or bone are not often researched. Patients with more severe wounds are not given treatment options that adequately address their needs, leading to a last resort of amputation.
In the case of pressure injuries, early surgical closure of wounds can decrease hospitalization and morbidity. However, the decision to reconstruct these wounds presents physicians with complex considerations. The huge loss of skin, fat, and sometimes muscle renders Stage 3 and 4 pressure injuries often refractory to conservative surgical approaches. The most common method is local tissue rearrangement and flap reconstruction with closure rates as low as 5% and 30% at 8 and 12 weeks for stage II to IV pressure injuries. In addition to low efficacy, physicians report startling complication rates like infection, low blood flow and neuropathy for patients undergoing surgeries for stage 3-4 pressure injuries.
AM: Explain the science behind SkinTE. How might this product overcome some of the challenges of other chronic wound treatments?
RH: SkinTE is an innovative investigational alternative made of a patient’s own full-thickness skin. SkinTE retains a patient’s endogenous regenerative cellular populations to promote the healing of hard-to-treat wounds. By developing an autologous product to treat wounds, we hope to circumvent problems of xenogeneic or allogeneic treatments where the body recognizes harvested cells and graft rejection and increase the speed of delivering this solution to the patient.
Physicians harvest a small, centimeters-sized area of full-thickness skin from the donor site that contains multicellular segments of regenerative cellular populations, usually from the back of a patient’s leg. This procedure can be performed outpatient under local anesthesia as well as inpatient as required, avoiding frequent and time-consuming appointments for wound care teams and patients.
The skin sample is shipped to PolarityTE’s lab and is processed into a paste that retains the regenerative quality of a patient’s skin. A quick response is often essential in treating serious wounds, and PolarityTE’s skin processing can be achieved in less than 48 hours. SkinTE is easily dispensed from a syringe in a paste-like consistency, spread across the wound, and covered with dressing until closure.
PolarityTE has submitted an IND to FDA for SkinTE for the use in chronic cutaneous ulcers. Their first pivotal trial is planned for Wagner 2 DFUs ranging up to 10cm2. PolarityTE plans to enrol a second pivotal study in another complex chronic wound type such as stage 3 and 4 pressure injuries. Ultimately, they plan to pursue approval for acute traumatic wounds, and burns as well. Finding a solution that can adapt to several types of wounds and severities will be crucial to improving patient outcomes.
AM: What future innovations do you foresee happening in the wound care space to improve patient outcomes?
RH: Wound care treatments must be adaptive and work with the patient’s own body, leveraging regenerative qualities of skin cells to promote wound healing. The future of wound care is shifting towards solutions that address all types of wounds, no matter the cause or severity. Patients with later-stage wounds are often given few alternatives to amputation, and health care professionals must find solutions that avoid this outcome. Amputations limit the mobility of patients; are costly to both patients and healthcare systems; and require surgery, routine check-ups, and physical therapy. The next generation of wound care must include biologically active therapies that can improve closure rates in highly compromised patients and that can be applied in a single, non-surgical application in multiple sites of care. At PolarityTE, we hope to be a part of the solution for patients with difficult-to-treat wounds.
Richard Hague was speaking to Anna MacDonald, Science Writer for Technology Networks.