Safety and Feasibility of Photodynamic Therapy for Percutaneous Image-guided Abdominopelvic Abscess Drainage: Phase 1 Trial.

Background Standard-of-care abscess management includes image-guided percutaneous drainage and antibiotics; however, cure rates vary, and concern for antibiotic-resistant bacteria is growing. Photodynamic therapy (PDT), which uses light-activated dyes to generate cytotoxic reactive oxygen species, could complement the standard of care by sterilizing the abscess at the time of drainage. Purpose To evaluate safety and feasibility of PDT with methylene blue (hereafter, MB-PDT) at the time of percutaneous abscess drainage. Materials and Methods This prospective, open-label, dose-escalation, first-in-humans, registered phase 1 clinical study of MB-PDT included participants who underwent percutaneous abdominal or pelvic abscess drainage with CT or US guidance from January 2015 to March 2020 and September 2022 to September 2023. Following drainage, MB-PDT was performed with laser illumination at a fluence rate of 20 mW/cm2, with fluence groups of 6, 12, 18, 24, 30, and 36 J/cm2 (n = 3 each). The primary outcome was safety, indicated by absence of fat embolism, MB escape, abscess wall damage, and need for surgery to remove optical fibers. Preliminary efficacy end points included the time to drainage catheter removal, drainage catheter output volume, and clinical symptom and fever duration. Relationships between fluence and outcomes were analyzed with Spearman correlation and linear regression analyses, and ordinary one-way analysis of variance was used for group comparisons. Results MB-PDT was safe and feasible in all 18 participants (mean age, 60.1 years ± 18.3 [SD]; 10 female), with no negative safety outcomes observed for any participant. No study-related adverse events were encountered, and the procedure did not increase reported pain (P = .1). Clinical symptom and fever duration was shorter in participants receiving higher fluences (30 and 36 J/cm2 vs 6 J/cm2) (P = .03). The presence of antibiotic-resistant bacteria was not predictive of clinical symptom and fever duration (ß = 0.13, P = .37). Conclusion MB-PDT was a safe and feasible adjunct to image-guided percutaneous abscess drainage. Clinical measures indicated a dose-dependent response to PDT. ClinicalTrials.gov registration no.: NCT02240498 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Johnston and Goldberg in this issue.

Photodynamic therapy is a safe and feasible adjunct to percutaneous drainage of deep tissue abscesses: Results of a first in humans Phase 1 clinical trial.

Background: Standard of care for abscess management includes image-guided percutaneous drainage and antibiotics. However, cure rates vary between patients and there is growing concern for antibiotic-resistant bacteria. Photodynamic therapy (PDT), which utilizes light-activated dyes to generate cytotoxic reactive species, could complement the standard of care by sterilizing the abscess at time of drainage. Purpose: The goal of this study was to perform a first in humans Phase 1 clinical study evaluating safety and feasibility of PDT with methylene blue (MB) at the time of percutaneous abscess drainage. This was accomplished through an open-label dose escalation study, with duration of light delivery escalated from 5-30 minutes. Materials and Methods: We performed MB-PDT in 18 subjects undergoing percutaneous abscess drainage. Following standard of care drainage, 1 mg/mL MB was delivered for 10 minutes. MB was aspirated, and 1% lipid emulsion infused to homogenize light dose at the cavity wall. An optical fiber was advanced to the approximate center of the abscess for 665 nm laser illumination at 20 mW/cm 2 . Results: MB-PDT at the time of abscess drainage was safe and feasible in all cases, with no evidence of fat embolism due to lipid emulsion or adverse reaction to MB observed. No study-related adverse or serious adverse events were encountered, and the procedure was well tolerated by all subjects. While the study was not designed or powered to determine efficacy, time to resolution of clinical symptoms was significantly decreased in subjects receiving higher fluences (p=0.028). Additionally, drainage catheter output post-procedure was decreased in subjects receiving higher fluences (ρ=-0.18), although this difference was not significant (p=0.43). Conclusion: MB-PDT is a safe and feasible adjunct to image-guided percutaneous abscess drainage. Clinical measures indicate a dose-dependent response to PDT, motivating future Phase 2 studies evaluating the efficacy of MB-PDT in this patient population.

Characteristics and outcomes of strabismus surgery after orbital decompression for thyroid eye disease.

PURPOSE: To compare characteristics and outcomes of strabismus surgery in patients who have undergone orbital decompression for thyroid eye disease with those who have not. SUBJECTS AND METHODS: A chart review of all patients with thyroid eye disease requiring strabismus surgery in one physician's practice. RESULTS: There were 36 patients in the decompression group (DG) and 14 patients in the no-decompression group (NDG). There was a significantly greater amount of preoperative esotropia in the DG ( P = 0.02). There was an increased incidence of A-pattern in the DG ( P = 0.09). There was a slightly higher number of operated muscles in the DG ( P = 0.005). A good or excellent outcome was achieved in 93% of the NDG and in 94% of the DG ( P = 0.83). DISCUSSION: Previous studies suggest that patients requiring orbital decompression have a more complex thyroid eye disease and a lower success rate after strabismus surgery. Our findings suggest that this is not necessarily the case, and the difference in surgical success rates between the studies may in part be due to orbital decompression technique or indication. CONCLUSION: In this series, using a fixed suture technique, outcomes of strabismus surgery in patients with thyroid eye disease who underwent orbital decompression are similar to those who did not.