Safety and efficacy of the swift microwave device in patients with mild-to-moderate onychomycosis: Protocol of an open-label, randomized, dose-finding pilot study.

Background: Onychomycosis is a common fungal nail disease with a prevalence rate up to 14% in North America and 24% in Europe. The current treatment paradigm is limited by a high risk of disease recurrence, safety concerns for oral agents, and a low likelihood of patients achieving both clinical improvement and mycological cure. Recent advances in device-based treatments have allowed for the direct targeting of the infection site that bypasses drug resistance mechanisms while minimizing systemic side-effects. The Swift^® System is a microwave device that has demonstrated therapeutic potential in treating skin (e.g. verrucae vulgaris, actinic keratosis) and nail infections.

Methods: We report the protocol of an open-label, randomized, pilot study that will be conducted at a single Canadian center. Our primary objective is to evaluate the safety and efficacy of microwave treatment (Swift^® System, Emblation Ltd, Scotland, U.K.), administered at three different dosing regimens, in 45 patients with mild-to-moderate distal subungual onychomycosis. Our secondary objective is to identify an optimal dosing regimen, if any, to better inform the conduct of a future pivotal trial. Patients will be randomized (1:1:1) to undergo either 9 treatment sessions (5 weekly sessions plus 4 monthly sessions), 7 treatment sessions (3 sessions every 2 weeks plus 4 monthly sessions), or 12 treatment sessions every 2 weeks. At each session microwave energy will be applied in 3-s intervals at 7-9 Watts, repeated up to 5 times at each treatment position on the nail. Overlapping treatment positions are used to ensure sufficient coverage of the infected area. Patients will be enrolled in the trial over a 12-month period. Efficacy will be evaluated based on visual improvement and mycology testing results. Adverse events will be recorded throughout the entire study period.

Discussion: This study will be the first to report on the safety and efficacy of microwave treatment in onychomycosis patients in a trial setting; recruitment is ongoing.

Trial registration: ClinicalTrials.gov, NCT05674747.