Aldara Mechanism of Action

Pharmacology:Pharmacodynamics: Imiquimod is an immune response modifier. It has no direct antiviral activity in cell culture. A mechanism of action study in 22 patients with genital/perianal warts shows that imiquimod induces cytokines including interferon-α at the treatment site. In addition, HPV E7 and L1mRNA as well as HPV DNA are significantly decreased following treatment. However, the clinical relevance of these findings is unknown.
Pharmacokinetics: Percutaneous absorption of [14C] imiquimod was minimal in a study involving 6 healthy subjects treated with a single topical application (5mg) of [¹⁴C] imiquimod cream formulation. No radioactivity was detected in the serum (lower limit of quantitation: 1ng/mL) and <0.9% of the radiolabelled dose was excreted in the urine and faeces following topical application.
Clinical Studies: In a double-blind, placebo-controlled clinical trial, Aldara Cream 5% w/w applied three times a week for treatment of genital and perianal warts had wart clearance rates that were statistically significantly greater than the placebo control. The percentage of patients achieving total clearance was 77% for females and 40% for males. The percentage of patients achieving partial wart area (>50%) reduction was 91% for female and 74% for male. The median baseline wart area was 69mm2 (range 8 to 5525 mm²). Visible wart changes occurred as early as 4 weeks and some patients required 16 weeks. The median time to total wart clearance was 10 weeks. In another study, Aldara Cream 5% w/w applied daily, 59% of the males and 84% of the females achieved total clearance of their genital/perianal warts. A low percentage (6-23%) of the patients who achieved total clearance of their warts experienced a recurrence of their warts during the 12-week follow-up period. In two studies, some patients achieved total clearance or additional reduction in wart area during a 4-week treatment-free observation period following Aldara Cream 5% w/w treatment. Thus, some patients with wart tissue remaining after Aldara Cream 5% w/w treatment may continue to show clearing of their warts.