Background: Resiquimod, a toll-like receptor 7 and 8 agonist, may be effective as a topical treatment of actinic keratosis (AK).
Objectives: To evaluate the effect of resiquimod gel concentration on lesion clearance.
Methods: Patients with AK lesions on the face or balding scalp were randomly assigned to resiquimod 0.01%, 0.03%, 0.06% or 0.1% gel applied once daily three times a week for 4 weeks to a contiguous 25-cm(2) area with four to eight lesions. Patients with persistent lesions received a second course after an 8-week treatment-free interval. Complete and partial lesion clearance was assessed 8 weeks after treatment for each course.
Results: For the 132 patients randomized, overall complete clearance rates were 77.1% (27/35), 90.3% (28/31), 78.1% (25/32) and 85.3% (29/34) and complete clearance rates after course 1 only were 40.0%, 74.2%, 56.3% and 70.6%, respectively, for the resiquimod 0.01%, 0.03%, 0.06% and 0.1% groups. During course 1, respectively 0%, 13%, 31% and 38% of patients discontinued treatment for adverse events or local skin reactions, for the resiquimod 0.01%, 0.03%, 0.06% and 0.1% groups. Possibly or probably related nonapplication site adverse events of severe intensity, including influenza-like symptoms, were reported by 0%, 3%, 13% and 12% of patients, respectively, for the resiquimod 0.01%, 0.03%, 0.06% and 0.1% groups.
Conclusions: Efficacy in clearing AK lesions was similar between the resiquimod concentrations evaluated, but resiquimod 0.01% and 0.03% were better tolerated than the higher concentrations.