Imiquimod Treatment Cuts Risk of Recurrent Actinic Keratoses

By M. Mary Conroy

NEW ORLEANS FEB 22, 2005 (Reuters Health) - Results of an observational study of patients treated for actinic keratosis (AK), suggest that long term use of imiquimod 5% cream substantially reduces risk of recurrence, researchers reported Monday at the 63rd annual meeting of the American Academy of Dermatology.

Eighteen months after start of treatment, the majority of patients showed no return of the pre-cancerous lesions and no untoward changes in the quality of the skin condition where the cream was applied, said Dr. Peter Lee of the University of Minnesota, Minneapolis.  Among subjects who did experience recurrence, "the number of lesions present in the original treatment area was low," he added.

Dr. Lee and colleagues studied 146 patients who achieved complete clearance of lesions while participating in 8-week Phase III clinical studies of imiquimod and followed patients who continued imiquimod use to evaluate long term effects. One hundred and thirty-one patients of the patients were in the imiquimod active treatment groups and 15 achieved total clearance while treated with a non-active vehicle cream.

Seventy-seven patients were treated with imiquimod three times a week for 16 weeks and 54 used imiquimod twice a week for 16 weeks.

After a median follow-up of 16 months, the recurrence rate in the thrice-weekly treatment group was 19.7%. The patients treated twice a week had a 42.6% recurrence rate.  Among the 15 patients whose AK cleared using placebo, the recurrence rate over 18 months was 46.7%. 

"No long-term safety issues or concerns with imiquimod use were seen in this study," Dr. Lee concluded. "None of the adverse events or local skin reactions noted at the time of the follow-up were considered to be clinically meaningful."

The study was funded by 3M Pharmaceuticals.


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