An exploratory, prospective, open-label trial of ingenol mebutate gel 0.05% for the treatment of external anogenital warts

Abstract

Background

Anogenital warts (AGW) can cause physical discomfort and decreased quality of life. Recent case reports suggest that ingenol mebutate gel might be an effective treatment of AGW.

Objective

To explore primarily the safety, and secondarily the efficacy of ingenol mebutate gel 0.05% in patients with AGW.

Methods

This was an exploratory, open-label, 1-arm trial of ingenol mebutate gel 0.05% administered up to 3 times to patients with AGW. Safety was assessed by occurrence and severity of local skin reactions (LSRs) and treatment-related adverse events (AEs). Efficacy was assessed by complete clearance and reduction in AGW count 14 days after last treatment, and recurrence 12 weeks after clearance.

Results

Of 41 patients enrolled, 40 received treatment and 26 completed the trial. Patients had a median AGW count of 11.0 and AGW duration of 3.0 years at baseline. All patients experienced transient LSRs following treatment with a maximum composite LSR score of 7.5 (on a scale from 0–18). 93% of patients reported treatment-related AEs, most frequently pain (85%) and procedural complications (35%) due to smearing of the gel. 78% of patients took mild analgesics for the pain, typically for 1-2 days following treatment. The majority of AEs were of moderate to severe intensity.

17/39 patients (43.6%) had complete clearance 14 days after last treatment, and AGW count was reduced by 90.9%. There was a tendency towards lower clearance rate in patients with longer duration of AGW. 14/8 patients (57.1%) had AGW recurrence 12 weeks after clearance.

Conclusion

Ingenol mebutate gel was associated with a high number of AEs and withdrawals due to painful local and adjacent skin reactions. Furthermore, it showed promising efficacy in reducing AGW despite a difficult-to-treat population. Optimisation of the formulation is warranted to improve the safety profile of the treatment.

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