Treatment

VP-102 is a proprietary drug-delivery device combination containing cantharidin, 0.7% (w/v), in a film-forming topical solution. The formulation also includes gentian violet, a surgical dye that facilitates the distinction between treated and untreated lesions during application, as well as denatonium benzoate, a bittering agent to deter potential oral ingestion.

The drug-device combination consists of a glass ampule containing 450 μL of solution within a single-use applicator. When the ampule is crushed, the solution is released to flow through a filter and into the tip of the applicator. VP-102 is stable at room temperature for storage and is manufactured under Good Manufacturing Practices, and the cantharidin used in VP-102 is more than 99% pure. The vehicle treatment was identical to VP-102 in all aspects (eg, applicator, smell, texture, color, appearance, and formulation) except for the lack of the active ingredient, cantharidin. Participants were required to be able to be treated with a maximum of 2 applicators of VP-102 or vehicle per treatment. The number of lesions per treatment was not limited in the trial.