Clinical safety and regenerative potential of a purified exosome product in treating skin graft donor sites: A phase 1b trial.

The objective of this study was to determine the safety of the first clinically used purified exosome product (PEP) for open wounds. This was a phase 1b, prospective, open-label, controlled, randomized clinical trial of PEP in subjects with at least two equal sized split-thickness skin graft (STSG) donor site wounds with one donor site treated with standard of care (SOC) and the other treated with PEP. Patients were divided into low-dose PEP-only group and high-dose PEP-only group. Safety evaluations included occurrence of adverse events, laboratory values, vital signs, and physical examination findings. Wound healing was scored using Vancouver scar scale (VSS) and photographic wound assessment tool (PWAT). Seven subjects were included, with a mean age of 49.3 years. There were no adverse events related to the treatments. We observed comparable wound healing time between the treatments, with PEP-treated sites reaching 100% re-epithelialization at a median of 18.5 days (range, 6-29 days) and 19.25 days (range, 8-314 days) for SOC sites, without a significant difference. This study demonstrated that a single application of PEP at a dose as high as 20% was safe in human participants. Future large trials will be needed to validate PEP efficacy in re-epithelialization and determine its clinical and statistical significance.