Imiquimod 5% cream for the treatment of superficial basal cell carcinoma: results from two phase III, randomized, vehicle-controlled studies.

Background: Imiquimod is an immune response modifier that is a Toll-like receptor 7 agonist that induces interferon and other cytokines through the innate immune system and stimulates cell-mediated immunity through T cells. Imiquimod has been shown to be efficacious as a topical treatment for basal cell carcinoma (BCC).

Objective: We sought to evaluate the efficacy and safety of imiquimod 5% cream compared with vehicle for treating superficial BCC (sBCC).

Methods: Two identical studies were conducted. Subjects with one sBCC were dosed with imiquimod or vehicle cream once daily 5 or 7x/week for 6 weeks in these 2 randomized, double-blind, vehicle-controlled Phase III studies. The lesion site was clinically examined 12 weeks posttreatment and then excised for histological evaluation.

Results: Data from both studies were pooled. Composite clearance rates (combined clinical and histological assessments) for the 5 and 7x/week imiquimod groups were 75% and 73%, respectively. Histological clearance rates for the 5 and 7x/week imiquimod groups were 82% and 79%, respectively. Increasing severity of erythema, erosion, and scabbing/crusting was associated with higher clearance rates.

Conclusion: Imiquimod appears to be safe and effective for the treatment of sBCC when compared with vehicle cream. The difference in clearance rates between the two imiquimod dosing groups was not significant. The 5x/week regimen is recommended.