Efficacy of imiquimod 3.75% from Lmax according to the number of actinic keratosis lesions

Abstract Background Imiquimod 3.75% reduces 92.2% of all actinic keratosis (AK) lesions, assumed to include both subclinicaland clinical lesions, across a large sun-exposed "eld such as the full face or balding scalp.Objective To evaluate the ef"cacy of imiquimod 3.75% using the reduction in lesions from Lmax (the maximum lesioncount during treatment) in subgroups of patients with low and high AK lesion counts.Methods Patients from two 14-week, placebo-controlled, double-blind studies were subgrouped according to whetherthey had ≤10 or >10 AK lesions at baseline. Treatment was applied to the full face or balding scalp during two 2-weektreatment cycles separated by a 2-week treatment-free interval.Results Overall, 167 patients had ≤10 lesions and 152 patients had >10 AK lesions at baseline. With imiquimod 3.75%,the median percentage reduction in AK lesions from Lmax to end of study was similar in patients with ≤10 and >10 base-line lesions (91.5% and 93.0% respectively). The median absolute reduction in AK lesions from Lmax to end of studywas 24.0 for patients with >10 baseline lesions and 10.0 for those with ≤10 baseline lesions. The median percentage andabsolute reductions in lesions from Lmax were signi"cantly greater with imiquimod 3.75% vs. placebo (P < 0.0001).Conclusions Imiquimod 3.75% is effective regardless of disease severity as shown in this study by the reduction ofover 90% of lesions from Lmax in patients with low or high AK lesion counts.Received: 5 June 2014; Accepted: 19 September 2014