Safety and Efficacy of Nano-Pulse Stimulation Treatment of Non-Genital, Cutaneous Warts (Verrucae)

Abstract

Background and objectives: This study describes the effects of nano-pulse stimulation (NPS) technology on the common verruca with the objectives of demonstrating efficacy and safety. NPS technology applies nanosecond pulses of non-thermal electrical energy to induce highly localized regulated cell death in the cellular structures of the targeted zone with negligible effects on surrounding non-cellular structures. Previous clinical studies applying NPS to common, benign skin lesions have demonstrated safety and efficacy in clearing seborrheic keratoses and sebaceous hyperplasia.

Study design/materials and methods: Sixty-two subjects were enrolled at a total of five sites. One hundred and ninety-five study verrucae up to 10 mm wide were treated with NPS delivered by a console-based handheld applicator (CellFX® System; Pulse Biosciences) and follow-ups occurred every 30 days with the option to retreat at 30, 60, and 90 days. There were 62 untreated controls and 46% of the treated verrucae were recalcitrant.

Results: Overall, 75.3% (70/93) of the common verrucae, 72.7% (8/11) of the flat verrucae, and 43.8% (14/32) of the plantar verrucae treated with NPS were completely clear by 60 days following the last treatment and did not recur within the 120-day observation period. The majority (54%) of verrucae cleared with a single NPS procedure. The most common treatment site reactions were erythema (50.5%) and eschar formation (23.4%) on Day 30 and on Day 120 mild erythema was present in 14% of the cases and hyperpigmentation in 18.5%. No serious adverse events were reported. A particle counter was used during 11 NPS procedures on verrucae and no significant plume generation was detected during these procedures.

Conclusions: NPS is a safe and effective procedure for removing non-genital, cutaneous verrucae. Lasers Surg. Med. © 2021 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals LLC.

Keywords: cutaneous verrucae; nano-pulse stimulation; nanosecond; pulsed electric fields; warts.

Fig. 1

Five types of applicator tips used in these treatments.

Fig. 2

Percentage of reduction in verruca size measured 60 days after the last nano‐pulse stimulation treatment.

Fig. 3

Recalcitrant finger verruca on a 51‐year‐old female with Fitzpatrick Class III skin type previously treated with an investigational product. (A–C) Day 0 before and after treatment; (D) Day 60; (E) Day 120. Moderate erythema, crust, and eschar formation were evident on Day 7 and retreatment with nano‐pulse stimulation occurred on Day 30. The white scale bar in each image indicates 5 mm.

Fig. 4

Knee verrucae on a 53‐year‐old female with Fitzpatrick Class II skin with no previous treatments. (A and B) Day 0 before and after 1st procedure session; (Cand D) Day 30 before and after 2nd session; (E) Day 60; (F) Day 120. Eschar formation and erythema present on Day 30, mild flaking and hyperpigmentation on Day 60, and mild hyperpigmentation and erythema observed on Day 120. White scale bars indicate 5 mm.

Fig. 5

Recalcitrant plantar verruca on a 21‐year‐old female with Fitzpatrick Class II skin type previously treated with cyrotherapy. (A) Pre‐treatment photo and (B) Pre‐treatment dermatoscope photo, (C) Post‐treatment dermatoscope photo Day 0 before the only procedure session; (D) Day 30 dermatoscope photo; (E) Day 90. Mild hyperpigmentation and eschar formation were present on Day 7 and a crust was present on Day 30. Cleared by Day 90. All white scale bars indicate 5 mm.

Fig. 6

Recalcitrant plantar verruca treated previously with cryotherapy on a 22‐year‐old female with Fitzpatrick class II skin type. (A) Before procedure; (B) Day 60; (C) Day 90. Mild flaking was observed on Day 60. All white scale bars indicate 5 mm.