Methylene blue photodynamic therapy of deep tissue abscesses: Phase 1 clinical trial and optical spectroscopy results

Abstract

SignificanceDeep tissue abscesses represent a significant source of morbidity and hospital stay, with standard of care drainage failing in many cases. We investigated photodynamic therapy (PDT) as an adjunct to standard of care, to reduce or eliminate bacterial burden. ApproachA Phase 1 clinical trial was performed to evaluate safety and feasibility of methylene blue (MB) PDT at the time of abscess drainage. Immediately following drainage, MB-PDT was performed. Diffuse reflectance spectroscopy was performed to evaluate abscess wall optical properties. ResultsNo study-related adverse events were noted, and no side effects were observed. PDT was well tolerated by all subjects, and infused MB was recovered in all cases. Optical property measurements showed variability in hemoglobin concentration and oxygenation, as well as MB uptake, between subjects. ConclusionsMB-PDT at the time of percutaneous abscess drainage was safe and feasible, and optical property measurements showed wide variance between subjects.