Imiquimod 2.5% and 3.75% for the treatment of actinic keratoses: results of two placebo-controlled studies of daily application to the face and balding scalp for two 2-week cycles.
BACKGROUND
The approved imiquimod 5% cream regimen for treating actinic keratoses requires a long treatment time and is limited to a small area of skin.


OBJECTIVE
We sought to evaluate imiquimod 2.5% and 3.75% for short-course treatment of the full face or balding scalp.


METHODS
In two identical studies, adults with 5 to 20 lesions were randomized to placebo, imiquimod 2.5%, or imiquimod 3.75% (1:1:1). Up to two packets (250 mg each) were applied per dose once daily for two 2-week treatment cycles, with a 2-week, no-treatment interval between cycles. Efficacy was assessed at 8 weeks posttreatment.


RESULTS
A total of 479 patients were randomized to placebo, or imiquimod 2.5% or 3.75%. Complete and partial clearance (> or =75% lesion reduction) rates were 6.3% and 22.6% for placebo, 30.6% and 48.1% for imiquimod 2.5%, and 35.6% and 59.4% for imiquimod 3.75%, respectively (P < .001 vs placebo, each; P = .047, 3.75% vs 2.5% for partial clearance). Median reductions from baseline in lesion counts were 25.0% for placebo, 71.8% for imiquimod 2.5%, and 81.8% for imiquimod 3.75% (P < .001, each active vs placebo; P = .048 3.75% vs 2.5%). There were few treatment-related discontinuations. Patient rest period rates were 0% for placebo, 6.9% for imiquimod 2.5%, and 10.6% for imiquimod 3.75%.


CONCLUSIONS
Local pharmacologic effects of imiquimod, including erythema, may have limited concealment of treatment assignment in some patients.


CONCLUSIONS
Both imiquimod 2.5% and 3.75% creams were more effective than placebo and were well tolerated when administered daily as a 2-week on/off/on regimen to treat actinic keratoses.
Swanson
Neil
N
Department of Dermatology, Oregon Health and Science University, Portland, Oregon 46032, USA. cwmhanke@thelassi.com
Abramovits
William
W
Berman
Brian
B
Kulp
James
J
Rigel
Darrell S
DS
Levy
Sharon
S
D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000634:Aminoquinolines / Q000008:administration & dosage*; D004304:Dosage Forms; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005145:Face; D005260:Female; D006801:Humans; D000077271:Imiquimod; D055623:Keratosis, Actinic / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012535:Scalp; D013997:Time Factors
D000276:Adjuvants, Immunologic; D000634:Aminoquinolines; D004304:Dosage Forms; D000077271:Imiquimod