Furosemide/Digoxin

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.

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.

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.

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.

This study demonstrates the proof of concept for the efficacy of topical ICVT in adults with cutaneous warts.

DNA viruses such as HPV rely on K+ influx for replication. Both digoxin and furosemide inhibit the K+ influx by interacting with cell membrane ion co‐transporters (Na+/K+‐ATPase and Na+‐K+‐2Cl− co‐transporter‐1, respectively). We therefore hypothesized that these two compounds in a topical formulation may be valuable in the treatment of HPV‐induced warts. This new approach is called Ionic Contra‐Viral Therapy (ICVT).

To evaluate systemic exposure, safety and tolerability of ICVT with a combination of furosemide and digoxin after repeated topical application in subjects with common warts. Furthermore, we aimed to evaluate pharmacodynamics effects of ICVT.

Twelve healthy subjects with at least four common warts on their hands were included in the study and treated with a fixed dose of 980 mg topical gel containing 0.125% (w/w) digoxin and 0.125% (w/w) furosemide for 7 consecutive days on their lower back to assess safety and systemic exposure. Two warts were treated with 10 mg each and two served as negative controls to obtain preliminary evidence of treatment effect.

ICVT was well tolerated topically, and there was no evidence of systemic exposure of digoxin or furosemide. There were no clinical relevant safety findings and no serious adverse events (SAEs). A rapid and statistically significant reduction in diameter, height and volume of the warts was already observed at day 14.

ICVT was found to be safe for administration to humans and 7 days of active treatment showed a statistical significant wart reduction compared to untreated control lesions, clearly indicating pharmacological activity.