Magic Wand? 2 Novel Systems for Diabetic Foot Enter Clinical Trials

Becky McCall

May 22, 2014

Two innovative methods to remove dead tissue and control infection in diabetic foot ulcers and chronic wounds have recently entered first-in-human trials.

The first, the WoundWand Debridement Device (ArthroCare), uses radiofrequency energy to gently and precisely dissolve soft tissue, while the second, a novel Limb Recovery System (Osprey Medical), delivers a high concentration of antibiotics via percutaneous isolated limb perfusion to the foot only.

If the systems are ultimately successful in clinical trials, they have the potential to minimize serious complications, including amputation, and could therefore significantly improve quality of life and clinical outcomes for patients with diabetes, the researchers say.

Clinical Trial of WoundWand Hopes to Recruit 60 Patients

Improper removal of dead tissue from infected wounds can have very serious consequences for patients, said co–principal investigator of the WoundWand study, Frank Bowling, MD, of the Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, United Kingdom.

"Foot ulcers and chronic wounds are among the most devastating complications of diabetes, and currently debridement [using scalpel blade] remains the standard of care. There remains, however, a relatively high potential for the debrided ulcers to become infected — a circumstance that markedly increases the risk of amputation," he told Medscape Medical News.

He and joint principal investigator, Tawqeer Rashid, MD, from the department of vascular surgery at Central Manchester University Hospitals NHS Foundation Trust, have just recruited the first patient into the WoundWand study, which grew out of encouraging results from preclinical studies at the University of Gothenburg, Sweden, published in Journal of Hospital Infection in 2013, Dr. Bowling noted.

The model used in the preclinical study relied on a Staphylococcus aureus biofilm grown on porcine dermis. The WoundWand was compared with standard curette and other debridement methods in terms of logarithmic-scale bacterial reduction and histological appearance postdebridement.

"Significant bacterial count reductions were measured after debridement with the WoundWand, and those observations compared favorably to other debridement methods," he explained. "These compelling preclinical data are the reason why scientific work has begun testing the effect of the WoundWand Debridement Device in humans."

The WoundWand utilizes exclusive plasma-mediated bipolar radiofrequency (Coblation) to ablate tissue via nonthermal molecular dissociation.

Despite only now entering trials for diabetic infection, Coblation technology has been used for over 20 years in sports medicine and otolaryngology procedures, including tonsillectomies, in more than 6 million cases worldwide.

The prospective, randomized, multicenter, clinical study will evaluate the effectiveness of using WoundWand compared with debridement using a scalpel blade to assess the difference in bacterial count, reduction in wound size, and improved recovery. The researchers hope to recruit 60 patients into the study by year-end.

Patients, who are blinded to treatment modality across the entire study period, are being assessed weekly for 4 weeks and again at 6 and 12 weeks after their debridement procedure. A digital camera with 3D wound measurement capabilities will be used to collect images to download and measure pre– and post–wound debridement.

Dr. Bowling explained that the primary end point of the study is to determine the bacterial diversity and number of bacteria present at 4 weeks' postdebridement using either the WoundWand Debridement Device or standard of care. "Secondarily, we will look at the reduction in wound size for up to 12 weeks' postdebridement."

Osprey Medical's Limb Recovery System

Meanwhile, researchers have recently completed a 5-patient pilot trial of Osprey Medical's Limb Recovery System, in which safe, targeted delivery of antibiotics to the lower limb was achieved, with significant reductions in bacterial load of the diabetic foot infection.

The system employs percutaneous isolated limb perfusion, enabling use of higher doses of antibiotics than standard delivery mechanisms allow, the investigators explain.

Details of this pilot trial were presented at the Diabetic Foot Global Conference 2014 in Los Angeles, California, in March.

Paul Wraight, MD, consultant at the diabetic foot unit, Royal Melbourne Hospital, Victoria, Australia, who led the research, said the results are very encouraging and related one impressive case study.

"One study patient had been scheduled for amputation prior to being enrolled in the pilot trial, but this was canceled, given the excellent improvement in infection as a result of percutaneous isolated limb perfusion," he explains in a company statement. "Obviously, this is anecdotal evidence from a small pilot trial, but it provides optimism for our larger, randomized efficacy trial."

Commenting, David G. Armstrong, DPM, MD, professor of surgery and director of the Southern Arizona Limb Salvage Alliance (SALSA), University of Arizona College of Medicine, Tucson, who was not involved in this research, said: "The concept of delivering a high level of antibiotics locally with a lower risk of negatively affecting the rest of the patient is not only attractive but downright exciting. We very much look forward to further work in this area."

Osprey Medical and Dr. Wraight are currently recruiting for a 20-patient efficacy trial that will evaluate the effectiveness of the system compared with standard-dose intravenous antibiotic delivery. This is expected to be completed by year-end.

The WoundWand study is supported by the National Institute for Health Research (NIHR) Clinical Research Network. Dr. Bowling has reported no relevant financial relationships. Osprey's Limb Recovery System was developed at Melbourne's Baker IDI Heart and Diabetes Institute and licensed to Osprey Medical. Dr. Wraight and Dr. Armstrong have reported no relevant conflicts of interest.

Diabetic Foot Global Conference 2014; March 20-22, 2014. Abstract

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