Topical imiquimod: a review of its use in genital warts

Imiquimod is a topically active immunomodulatory agent that is formulated as a 5% cream for application by the patient. It is the first agent of its class, the immune response modifiers, to be used in the treatment of genital warts. In immunocompetent patients with genital warts, imiquimod stimulates the production of interferon-alpha and various other cytokines, and has indirect antiviral activity. In randomised, double-blind, vehicle-controlled clinical trials, complete clearance of warts occurred in 37 to 50% of immunocompetent patients with genital warts treated with imiquimod 5% cream 3 times a week for up to 16 weeks; partial clearance of warts (defined as a reduction in wart area of > or = 50%) was observed in 76% of recipients of imiquimod 5% cream. Rates of complete or partial clearance of warts were significantly higher in patients who applied imiquimod 5% cream 3 times a week than in recipients of imiquimod 1% or vehicle cream, each applied 3 times a week. A between-gender difference in clinical response to imiquimod 5% cream has been reported, with female patients experiencing higher rates of complete clearance of warts than males. Recurrence(s) of > or = 1 wart occurred in 13 to 19% of immunocompetent patients in whom complete clearance of warts had been achieved with imiquimod 5% cream. Imiquimod 5% cream also shows some clearance of warts in immunosuppressed HIV-infected patients with genital warts. Preliminary results of a vehicle-controlled study showed that the rate of partial clearance of warts (defined as a reduction in baseline wart area of >50%) [38%] was significantly higher with imiquimod 5% cream than with vehicle cream; however, the rate of complete clearance was not significantly higher than with vehicle cream. Imiquimod 5% cream is generally well tolerated by immunocompetent and HIV-infected patients. Local skin reactions (mainly mild or moderate), including erythema, itching and burning, are the most commonly reported adverse events, occurring in < or = 67% of patients applying imiquimod 5% cream 3 times a week. The incidence of adverse events is lower in patients applying the cream 3 times a week than with daily application. The incidence of systemic adverse events with imiquimod 5% cream (applied daily or 3 times a week) is similar to that of vehicle cream. The tolerability profile of imiquimod cream appears favourable compared with that of podophyllotoxin.

Imiquimod 5% cream is a new therapeutic option for patients with genital warts. It produces clearance rates broadly similar to those of other treatment approaches and rates of wart recurrence compare favourably with those reported for established treatments. In contrast to most alternative treatment strategies. which are administered in the physician's office, imiquimod cream is a self-administered therapy for outpatient use.