Long-term sustained lesion clearance from Lmax with imiquimod 3.75%, a new field-directed treatment for actinic keratosis.

BACKGROUND: In patients with actinic keratosis (AK), subclinical and clinical lesions coexist across large areas of sun-exposed skin. The long-term efficacy of AK treatments depends on their ability to eradicate both types of lesions across the entire field. OBJECTIVE: To assess the long-term efficacy of imiquimod 3.75% using the reduction in lesions from Lmax (maximum lesion count during treatment), which assesses the ability to clear subclinical and clinical lesions. METHODS: Patients with 5-20 AK lesions on the full face or balding scalp from two 14-week, randomized, vehicle-controlled, double-blind studies of imiquimod 3.75% (daily for two 2-week treatment cycles separated by a 2-week treatment-free period) were eligible to enter a 12-month follow-up study if they had no AK lesions at Week 14. Lesion reduction from Lmax was calculated at 6 and 12 months during follow-up. RESULTS: The 42 patients in this long-term study had a median of nine baseline lesions and a median Lmax of 22 lesions. At 6 and 12 months of follow-up, the median absolute reduction in AK lesions from Lmax with imiquimod 3.75% was 21 and 19, respectively. The median percentage reduction in lesions from Lmax to 6 and 12 months was 100% and 97.2%, respectively. CONCLUSIONS: The ability of imiquimod 3.75% to eliminate clinical and subclinical lesions across an entire sun-exposed field translates into sustained long-term efficacy. Imiquimod 3.75% may therefore represent a first-choice treatment for patients with AK.

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

BACKGROUND: Imiquimod 3.75% reduces 92.2% of all actinic keratosis (AK) lesions, assumed to include both subclinical and clinical lesions, across a large sun-exposed field such as the full face or balding scalp. OBJECTIVE: To evaluate the efficacy of imiquimod 3.75% using the reduction in lesions from Lmax (the maximum lesion count 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 whether they had ≤ 10 or >10 AK lesions at baseline. Treatment was applied to the full face or balding scalp during two 2-week treatment 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 baseline lesions (91.5% and 93.0% respectively). The median absolute reduction in AK lesions from Lmax to end of study was 24.0 for patients with >10 baseline lesions and 10.0 for those with ≤ 10 baseline lesions. The median percentage and absolute reductions in lesions from Lmax were significantly 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 of over 90% of lesions from Lmax in patients with low or high AK lesion counts.