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 3-week cycles.
BACKGROUND
Imiquimod 5% cream is approved as a 16-week regimen for the treatment of actinic keratoses involving a 25-cm(2) area of skin.


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


METHODS
In two identical studies, adults with 5 to 20 lesions were randomized to placebo, or imiquimod 2.5% or 3.75% cream (1:1:1). Up to two packets (250 mg each) were applied per dose once daily for two 3-week treatment cycles, with a 3-week, no-treatment interval. Efficacy was assessed at 8 weeks posttreatment.


RESULTS
In all, 490 subjects were randomized to placebo, or imiquimod 2.5% or 3.75% cream. Median baseline lesion counts for the treatment groups were 9 to 10. Complete and partial clearance rates were 5.5% and 12.8% for placebo, 25.0% and 42.7% for imiquimod 2.5%, and 34.0% and 53.7% for imiquimod 3.75% (P < .001, each imiquimod vs placebo; P = .034, 3.75% vs 2.5% for partial clearance). Median reductions from baseline in lesion count were 23.6%, 66.7%, and 80.0% for the placebo, imiquimod 2.5%, and imiquimod 3.75% groups, respectively (P < .001 each imiquimod vs placebo). There were few treatment-related discontinuations. Temporary treatment interruption (rest) rates were 0%, 17.1%, and 27.2% for the placebo, imiquimod 2.5%, and imiquimod 3.75%, respectively.


CONCLUSIONS
Local effects of imiquimod, including erythema, may have led to investigator and subject bias.


CONCLUSIONS
Both imiquimod 2.5% and 3.75% creams were more effective than placebo and had an acceptable safety profile when administered daily as a 3-week on/off/on regimen.
Laser and Skin Surgery Center of Indiana, Carmel, Indiana 46032, USA. cwmhanke@thelassi.com
C William
CW
Hanke
Kenneth R
KR
Beer
Eggert
E
Stockfleth
Jason
J
Wu
Theodore
T
Rosen
Sharon
S
Levy
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