Wound Healing Endpoint and Recurrence

In the United States, chronic wounds represent a major public health burden. Estimates put the number of chronic wounds cases at over 6.5 million with a cost burden of over $50 billion14. According to the current standard of care (SoC), wound closure is assessed visually. The FDA defines complete wound closure of chronic non-healing wounds as "skin closure (as assessed visually) without drainage or dressing requirements identified at two consecutive study visits that are 2 weeks apart" and requires therapeutic trials for chronic wounds to be designed such that the enrolled patients will be evaluated for at least 3 months following completeclosure19. The expectation is that successful intervention should keep the wound closed for at least 90 days. This study contends that visual inspection of wounds is insufficient to certify closure - a critical endpoint that drives treatment decisions. Considering that almost two-thirds of all chronic wounds are estimated to be biofilminfected6, and the observation that biofilm-infected wounds may be visually closed but functionally (barrier function) open, the significance of the proposed hypothesis is substantial. The proposed study has the clear potential to lay a strong rationale that would potentially change the wound care paradigm by requiring that measurement of skin barrier function be the new endpoint to define wound closure. Reported recurrence rates for most chronic ulcer types remain extremely high, ranging from 40-79%4,5, 24%-57% for venous ulcers, and upward of 60% for diabetic ulcers supporting the importance of preventive efforts1,2. In that context it is of extraordinary significance to ask whether "defective closure" (visually closed with TEWL (Trans-Epidermal Water Loss) \>3x the value of intact skin; high TEWL) predicts poor post-closure outcome e.g. recurrence. These questions may only be meaningfully asked in a patient-based pilot and that is exactly the intent of Aim 2. Findings of the proposed pilot will inform a larger future trial.