Placebo-controlled, double-blind, randomized pilot study of imiquimod 5% cream applied once per week for 6 months for the treatment of actinic keratoses

Background: Imiquimod 5% cream applied twice weekly for 16 weeks is effective for treating actinic keratoses but may be limited by local side effects. Objective: We sought to explore the efficacy and safety of a once weekly for 24 weeks dosing regimen using a left versus right side of head design. Results: Twenty patients were enrolled; 15 completed and 5 discontinued for reasons unrelated to adverse events. At the posttreatment visit (week 28), 7 (46.7%) of 15 patients had marked improvement or better on the imiquimod side versus one (6.7%) of 15 on the placebo side. The average investigator assessment scale score change was +2.20 for imiquimod compared with -0.27 for placebo (P = .0002, Wilcoxon signed rank test). Skin reactions were minimal or nonexistent in most patients. Limitations: Limitations of the study include a small sample size and a lack of objective measure of local side effects. Conclusion: Imiquimod 5% cream applied once weekly for 24 weeks was convenient for patients and resulted in improvement of actinic keratoses with minimal side effects.