Antimicrobial Peptide Treatment to Combat Wound Biofilm

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ABSTRACT The goal of this work is to develop a treatment for non-healing and chronic wounds that will prevent wound biofilm and facilitate healing. Chronic wounds affect approximately 6.5 million patients in the US with annual treatment cost up to $50 billion. Despite high treatment costs, approximately 30% of patients will not heal using existing interventions and many wounds progress to serious infections, including amputation. Recent studies indicate that over 75% of chronic wounds harbor biofilms, which is considered a key barrier to successful treatment. There is increasing evidence that biofilms impair healing and are associated with the transition of wounds to a chronic non-healing state with the involvement of drug resistant organisms and multispecies biofilms is gaining recognition as an important factor in this process. Current antimicrobial products used to manage wound bioburden are not effective against biofilm and deliver agents that can cause irritation, cytotoxicity and impair healing. New therapeutics are needed that are effective against biofilms and conducive to healing that can be used to reduce pain and odor, improve functional outcomes, and improve quality of life for those with chronic wounds. The goal of this work is to develop an antimicrobial wound treatment based on an engineered cationic antimicrobial peptide called ASP-2 that is broad spectrum and effective against biofilms including those of multidrug resistant bacteria. ASP-2 displays significantly greater specificity for bacteria cells versus host cells relative to silver and other antiseptics commonly used in wound care. This provides greater biocompatibility, which is critical to remove barriers to wound resolution and improve healing. The Phase II project aims build on strong preliminary data from Phase I that established the broad-spectrum activity of a lead peptide, ASP-2, and its capacity to eradicate biofilms under conditions relevant to wound treatment. In Phase I, chitosan formulations were developed as a compatible vehicle for sustained application and delivery of the peptide. ASP-2 loaded formulations were shown to be effective against biofilms in a challenging ex vivo porcine skin biofilm model and in significantly reducing bioburden in a porcine excisional infected wound model. In Phase II, the product formulation will be further developed and optimized for efficacy, ease of use, and shelf stability. Lead formulations will be tested against single species and polymicrobial biofilms using an ex vivo porcine skin biofilm model followed by an evaluation of efficacy and healing in a porcine excisional infected wound model. Nonclinical safety studies will be initiated including key toxicity studies and a regulatory strategy with a detailed nonclinical development plan will be prepared. Success of this project will have a significant impact on reducing morbidity and improving the quality of life of patients with chronic wounds. Because the cost of wound treatment scales with time to closure, the product also has potential to reduce overall treatment costs.