Aldara – Imiquimod is an immune response modifier. Aldara topical is used to treat actinic keratosis (a condition caused by too much sun exposure) on the face and scalp. It is also used to treat a minor form of skin cancer called superficial basal cell carcinoma, when surgery would not be an appropriate treatment. Aldara – Imiquimod topical also treats genital warts that appear on the outside of the body, but this medicine is not a cure for genital warts. CLINICAL PHARMACOLOGY Pharmacodynamics Actinic Keratosis The mechanism of action of Aldara Cream in treating actinic keratosis (AK) lesions is unknown. In a study of 18 patients with AK comparing Aldara Cream to vehicle, increases from baseline in week 2 biomarker levels were reported for CD3, CD4, CD8, CD11c, and CD68 for Aldara Cream treated patients; however, the clinical relevance of these findings is unknown. Superficial Basal Cell Carcinoma The mechanism of action of Aldara Cream in treating superficial basal cell carcinoma (sBCC) lesions is unknown. An open label study in six subjects with sBCC suggests that treatment with Aldara Cream may increase the infiltration of lymphocytes, dendritic cells, and macrophages into the tumor lesion; however, the clinical significance of these findings is unknown. External Genital Warts Imiquimod has no direct antiviral activity in cell culture. A study in 22 patients with genital/perianal warts comparing Aldara Cream and vehicle shows that Aldara Cream induces mRNA encoding cytokines including interferon- at the treatment site. In addition HPVL1 mRNA and HPV DNA are significantly decreased following treatment. However, the clinical relevance of these findings is unknown.