Randomized Phase IIa Trial of Purified Candida Antigen for Common Warts: Evaluating the Safety and Efficacy Across...

Non-standardized Candida albicans antigens are commonly used for the treatment of common warts (verruca vulgaris); however, clinical studies thus far have not determined optimal dosing. This study assessed three dosing schemes using Candin®, a standardized purified Candida antigen (PCA), for the treatment of common warts.

This placebo-controlled, randomized phase IIa clinical trial included participants that had 3 to 20 injectable common warts on prespecified anatomical regions. PCA was administered intralesionally for up to 10 injections every 2 weeks, with adjustments to every 3 weeks for local tolerance issues. Three dosing regimens were evaluated: 0.3 or 0.5 mL into a single wart (cohorts 1 and 2, respectively), or 0.3 mL into up to four warts (cohort 3). Total injection volumes in cohorts 2 and 3 were larger than the typical off-label use of C. albicans. The primary outcome was complete resolution of injected warts, while secondary outcomes included safety, tolerability, and the clearance of untreated common warts.

The incidence of clearance of the primary injected wart in placebo participants was 41.9%, compared to 65.9% (relative risk [RR] 1.57; 95% confidence interval [CI] 1.02, 2.42; P = 0.03) in cohort 1, 79.5% (RR 1.89; 95% CI 1.27, 2.82; P = 0.0007) in cohort 2, and 72.5% (RR 1.74; 95% CI 1.19, 2.50; P = 0.005) in cohort 3, and treatment was well tolerated. Injection of 0.5 mL PCA into a single wart also resulted in a significantly higher rate of clearance of untreated common warts compared to placebo (RR 3.2, 95% CI 1.2, 8.0, P = 0.001).

All three dosing regimens of PCA were safe, well tolerated, and resulted in significantly greater clearance of the primary treated wart(s) compared to placebo, but only 0.5 mL injected into a single wart was significantly better than placebo at clearing untreated warts. Typically, a volume of 0.3 mL C. albicans antigen is injected into a single wart; however, these results suggest that a larger volume of 0.5 mL may have greater benefit for patients. A phase III clinical trial is currently underway to confirm these findings.

ClinicalTrials.gov NCT02393417.