Two-year interim results from a 5-year study evaluating clinical recurrence of superficial basal cell carcinoma after treatment with imiquimod 5% cream daily for 6 weeks.

Imiquimod 5% cream is approved in the USA, Europe and Australia to treat superficial basal cell carcinoma, using a regimen of once daily, 5 times per week for 6 weeks. Vehicle-controlled, phase III clinical trials show that imiquimod is safe and effective for treating superficial basal cell carcinoma with dosing 5 or 7 times per week for 6 weeks. This phase III, open-label study evaluates the long-term (5 years) clinical efficacy and safety of dosing once daily, for which this manuscript reports the 2-year time point in the follow-up period. For the 169 enrolled subjects, the tumour selected for treatment was assessed clinically to determine initial clearance at the 12-week post-treatment visit. If clinically clear of superficial basal cell carcinoma, subjects entered a 5-year, long-term follow-up period. Subjects were evaluated for recurrence at the 3-, 6-, 12- and 24-month follow-up visits. The initial clearance rate at 12 weeks post treatment was 94.1%. The proportion of subjects who were clinically clear at the 2-year follow-up visit was estimated to be 82.0%. Imiquimod was tolerated when applied daily, with erythema reported for all subjects participating in the study. The recurrence rate observed suggests that once daily dosing and 5x/week dosing yield similar clearance rates, but daily dosing increases local skin reactions.