A randomized controlled proof-of-concept trial of digoxin and furosemide in adults with cutaneous warts

Background Topical ionic contraviral therapy (ICVT) with digoxin and furosemide inhibits the potassium influx on which DNA viruses rely for replication. Therefore, ICVT was hypothesized to be a potential novel treatment for cutaneous warts. Objectives To assess the clinical efficacy, safety and tolerability of ICVT in adults with cutaneous warts. The secondary objective was to gain insight into the underlying working mechanism of ICVT. Methods Treatment with ICVT was assessed for efficacy, safety and tolerability in a single-centre, randomized, double-blind, placebo-controlled phase IIA trial. Eighty adult patients with at least two cutaneous warts (plantar or common) were randomized to one of four treatments: digoxin + furosemide (0.125%), digoxin (0.125%), furosemide (0.125%) or placebo. The gel was administered once daily for 42 consecutive days. Predefined statistical analysis was performed with a mixed-model ANCOVA. The trial was registered at ClinicalTrials. gov with number NCT02333643. Results Wart size and human papillomavirus (HPV) load reduction was achieved in all active treatment groups. A statistically significant reduction in wart diameter of all treated warts was shown in the digoxin + furosemide treatment group vs. placebo (3.0 mm, 95% confidence interval . 4 . 9 to . 1 . 1, P = 0 . 002). There was a statistically significant reduction in the HPV load of all treated warts in the digoxin + furosemide group vs. placebo (. 94%, 95% confidence interval . 100 to . 19, P = 0 . 03). With wart size reduction, histologically and immunohistochemically defined viral characteristics disappeared from partial and total responding warts. Conclusions This study demonstrates the proof of concept for the efficacy of topical ICVT in adults with cutaneous warts.