TCP-25 Gel Reduces Bacterial Burden and Inflammation in Human Epidermal Wounds: Exploratory Analyses from a Randomized Placebo-Controlled Trial

The innate immune system controls bacterial growth and modulates inflammation during wound healing. TCP-25 is a synthetic thrombin-derived host-defense peptide that combines direct antibacterial activity with neutralization of microbial products and modulation of CD14-dependent inflammatory signaling. We investigated whether this dual mechanism translates to human wounds using longitudinal samples from 24 healthy volunteers enrolled in a randomized, double-blind, within-participant, placebo-controlled phase I dose-escalation study of topical TCP-25 gel in matched epidermal suction blister wounds. We assessed inflammatory cytokines, neutrophil-derived proteins, wound exudation, cultivable bacterial burden, spatial bacterial distribution, and microbiome composition. TCP-25 reduced multiple cytokines, myeloperoxidase, and heparin-binding protein, with the strongest effects observed during the peak inflammatory phase. These changes were accompanied by reduced wound exudation and significant reductions in cultivable bacterial burden. Despite this antibacterial effect, microbiome composition and diversity remained largely unchanged, and participant-specific microbial profiles were preserved. TCP-25 therefore coordinated bacterial control, modulation of the physiological inflammatory response, and reduced wound leakage without major disruption of the resident microbiota composition. These findings provide clinical support for translating nature's endogenous host-defense principles into new therapies for complex wounds.