A guide to immunotherapy of genital warts - Focus on interferon and imiquimod

Genital warts affect at least 1% of sexually active adults. Current therapi es are inadequate because they are often painful, may fail to prevent recur rence and transmission of warts, and usually require either surgery or at l east application by a physician. Investigation of immunotherapy for genital warts began with interferon. It has been studied in topical, intralesional , systemic and adjuvant applications. We review the major clinical trials o f interferon for genital warts, and conclude that intralesional therapy wit h interferon-alpha or interferon-beta, with complete response rates of 36 t o 63%, is the most successful route for interferon monotherapy. In choosing patients for therapy with interferon, major considerations include immune status, pregnancy and ability to return for frequent injections. Imiquimod is a new immune response enhancer that acts through stimulating h ost cytokine production. Interleukins-1, -2, -6, -8 and -12, interferons al pha, beta and gamma and tumour necrosis factor alpha have all been associat ed with the mechanism of action of imiquimod. Recently, 3 clinical trials h ave reported positive results using topical imiquimod to treat genital wart s. Complete response rates ranged from 37 to 54% for these controlled trial s of 5% imiquimod cream. Adverse effects reported include localised pruriti s, erythema, erosion, burning and pain, which were rarely severe enough to cause discontinuation of the medication. Although further trials art: neces sary to identify the role of imiquimod in the therapy of genital warts, it appears to be tin efficacious and well tolerated patient-controlled measure for wart therapy.