(CS-101) Purified Exosome Product Enhances Skin Graft Donor Site Healing: A Phase 1b Clinical Trial

Atta Behfar, MD, PhD; Chris Paradise, PhD; Rou Wan, MD

Introduction: Exosomes represent the latest cell-free strategy in wound care.  However, a readily available clinical grade exosome product is lacking.  Purified Exosome Product (PEP) is a novel, off the shelf, clinical-grade exosome product derived from human platelets, with consistent batch quality and a shelf life of 24 months at room temperature.  This study aimed to evaluate the safety of PEP in the treatment of open wounds.

Methods: This was a phase 1b, open labeled controlled randomized clinical trial of PEP in subjects with at least two split thickness skin graft (STSG) donor sites.  There were two treatment groups: 10% PEP and 20% PEP.  The participants served as their own controls by comparing one wound site receiving the standard of care (SOC) and the other treated with PEP. The subjects were followed for 6 months.  Safety evaluation included occurrence of adverse events, laboratory values, vital signs, and physical examination findings.  The quality of the regenerated skin was scored using the Vancouver scare Score (VSS) and Photographic Wound Assessment Tool (PWAT)

Results: Seven subjects were enrolled, with a mean age of 49.3 years. There were no adverse events related to the treatment.  The application of PEP significantly accelerated wound healing (Figure 1), with the PEP-treated sites reaching 100% re-epithelization in an average of 21.8 days, compared to 60.6 days for the SOC sites (P< 0.05). The median VSS score was the lowest in the 20% PEP group after 6 months in all groups.  The median PWAT score was significantly reduced int eh 20% PEP group compared to the 10% PEP group at 3 months and 6 months (p< 0.05).

Discussion: This study demonstrates that a single application of PEP at a dose as high as 20% was safe.  There were signs of significantly accelerated re-epithelization in the PEP treated wounds compared to SOC, with a dose response effect.  This is the first FDA approved clinical study evaluating the safety of PEP on human wound healing.  PEP contains trillions of active platelet-derived regenerative exosomes and represents the first commercially viable exosome-based treatment.