COVE-1: A Phase 2, Open-Label Study to Evaluate Efficacy and Safety and the Optimal Regimen of VP-102, a Proprietary Drug–Device Product Containing Topical Cantharidin (0.7% w/v) Under Occlusion for the Treatment of Common Warts

INTRODUCTION: Verrucae vulgaris, or common warts, is a common skin condition for which there is no US Food and Drug Administration-approved treatment. Compounded cantharidin has been used to treat warts for years but lacks a controlled formulation, consistent application schedule and methods, and robust safety and efficacy studies. VP-102 is a proprietary drug-device combination product containing a topical formulation of 0.7% (w/v) cantharidin in a single-use delivery device. This objective of the phase 2 study was to evaluate the efficacy, safety, tolerability, and optimal regimen of VP-102 in the treatment of common warts. METHODS: In this open-label trial, participants aged ≥ 2 years with one to six common warts were administered VP-102 topically to treatable common warts once every 14 days (Cohort 1) or once every 21 days in conjunction with paring (Cohort 2), for up to four treatments. Participants were evaluated through to day 84 (Cohort 1) or day 147 (Cohort 2). The primary endpoint was the percentage of participants with complete clearance of all treatable common warts (baseline and new) at day 84. Secondary endpoints included percentage of participants achieving complete clearance of all treatable common warts at other visits. Safety assessments included treatment-emergent adverse events (TEAEs), including local skin reactions (LSRs). RESULTS: A total of 21 and 35 participants were enrolled in Cohort 1 and Cohort 2, respectively. Complete clearance at day 84 was seen in 19.0% of participants in Cohort 1 and 51.4% of those in Cohort 2. The most common TEAEs were expected LSRs and included application site vesicles, pain, pruritus, erythema, and scab. Most LSRs were mild or moderate in severity. CONCLUSION: VP-102 showed efficacy in complete clearance of common warts from baseline to day 84, as well as at follow-up visits. Due to the higher percentage of patients exhibiting complete clearance in Cohort 2, the treatment regimen of Cohort 2 will be pursued in future studies. TEAEs were expected due to the pharmacodynamic action of cantharidin, a vesicant. Clinical Trials ID: NCT03487549