A phase II dose-ranging study of topical resiquimod to treat actinic keratosis


  • Conflicts of interest
    This study was funded by 3M Pharmaceuticals, Saint Paul, MN, U.S.A. The investigating authors received payments for this research project. J.B., J.L. and T-C.M. were employees of 3M Pharmaceuticals at the time the study was conducted.

Rolf-Markus Szeimies.
E-mail: Rolf-Markus.Szeimies@klinik.uni-regensburg.de


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-cm2 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.