New perspective in immunotherapy: local imiquimod treatment

Imiquimod belongs to the family of synthetic small nucleotid-like molecules of imidazoquinolinamines. It is an immune response modifier with potent antiviral and antitumor effects, which are mediated by Toll-like receptors (TLR7 and TLR8). Imiquimod targets predominantly TLR7 expressing plasmacytoid dendritic cells and Langerhans cells, with secondary recruitment and activation of other inflammatory cells. Activation of TLR7 results in the stimulation of the innate and acquired immune responses, in particular cell mediated immune pathways. Topical imiquimod cream 5% (Aldara, MEDA Pharma) has been found to be effective for the treatment of actinic keratoses, superficial basal cell carcinoma and anogenital warts. Topical imiquimod is especially recommended for the treatment of large clinically asymptomatic fields containing tumor cells ("field cancerization"). Treatment with imiquimod applied at home by patient gives excellent cosmetic results. There are some data on its efficacy in nodular basal cell carcinoma and in some other skin cancers. The drug appears to be well tolerated with mild to moderate to local inflammation at the site of application. This paper provides a review about current experience and possible future development of imiquimod.