Vehicle-controlled, randomized, double-blind study to assess safety and efficacy of imiquimod 5% cream applied once daily 3 days per week in one or two courses of treatment of actinic keratoses on the head

Background Imiquimod has been investigated as a safe and effective therapeutic option for the treatment of actinic keratosis (AK). Objectives To evaluate imiquimod vs. vehicle applied three times a week for 4 weeks in one or two courses of treatment for AK on the face or balding scalp. Patients and methods Patients diagnosed with AK were enrolled in this multicentre, vehicle-controlled, double-blind study conducted in Europe. Twenty study centres enrolled a total of 259 patients in this study. Patients applied the study drug for 4 weeks, entered a 4-week rest period and if they did not have complete clearance, they then entered a second course of treatment. Results Patients in the imiquimod group had an overall complete clearance rate of 55.0% (71/129) vs. a rate of 2.3% (3/130) for the vehicle group. There was a high rate of agreement between the clinical assessment and histological findings with respect to AK lesion clearance. At both 8-week post-treatment visits, the negative predictive value of the investigator assessment was 92.2% for clinical assessments vs. histological results. Conclusions A 4-week course of treatment with three times weekly dosing of imiquimod 5% cream, with a repeated course of treatment for those patients who fail to clear after the first course of treatment, is a safe and effective treatment for AK. The overall complete clearance rate (complete clearance after either course 1 or course 2) is comparable to the 16-week treatment regimen, while decreasing drug exposure to the patient and decreasing the overall treatment time.