An Acid‐Oxidising Solution Containing Hypochlorous Acid Reduces <i>Staphylococcus aureus</i> and Improves Bacterial Diversity in Epidermolysis Bullosa Wounds

Epidermolysis bullosa (EB) is a group of rare genetic skin disorders characterised by skin fragility and chronic, painful wounds that are highly susceptible to bacterial infection, particularly by Staphylococcus aureus (SA). This study evaluated the efficacy of an acid-oxidising solution containing hypochlorous acid (HOCl) in reducing SA colonisation, promoting wound healing, and restoring a healthier microbiome in EB wounds. In a 12-week open-label pilot study, 15 EB patients applied the HOCl-based spray (APR-TD011) daily to chronic wounds for 8 weeks, with full-length 16S rRNA sequencing of wound swabs performed before, during, and after treatment. At baseline, 87% of patients were culture-positive for SA, and sequencing revealed that SA had the highest relative abundance (34%), followed by Acinetobacter guillouiae and Pseudomonas poae. SA relative abundance decreased precipitously by Weeks 4 (to 11%) and 8 (primary endpoint; to 10%, p < 0.01), and this effect persisted at 4 weeks post-treatment (Week 12; to 9.7%), including for methicillin-resistant SA. Concurrently, bacterial diversity increased, and wound sizes diminished in correlation with reduced SA levels (r = 0.64). Younger patients exhibited greater SA reduction trends. The treatment was well-tolerated, with minimal adverse effects and high patient satisfaction. This study underscores the role of microbial dysbiosis in EB wounds and highlights HOCl-based solutions as a promising therapy to mitigate pathogenic burden and enhance wound healing.