Imiquimod, a Patient-Applied Immune-Response Modifier for Treatment of External Genital Warts

Abstract

Genital human papillomavirus infection is one of the most common sexually transmitted diseases. Imiquimod is a new agent, an immune-response modifier, that has been demonstrated to have potent in vivo antiviral and antitumor effects in animal models. The present prospective, multicenter, double-blind, randomized, vehicle-controlled trial evaluated the efficacy and safety of daily patient-applied imiquimod for up to 16 weeks for the treatment of external genital warts. Wart recurrence was investigated during a 12-week treatment-free follow-up period. In the intent-to-treat analysis, baseline warts cleared from 49 of 94 (52%) patients treated with 5% imiquimod cream, 13 of 90 (14%) patients treated with 1% imiquimod cream, and 3 of 95 (4%) vehicle-treated patients; the differences between the groups treated with vehicle and imiquimod were significant (P< 0.0001). For subjects who completed the follow-up period, recurrence rates after a complete response were 19% (9 of 48 patients) in the 5% imiquimod cream group, 17% (2 of 12) in the 1% imiquimod cream group, and 0% (0 of 3) in the vehicle-treated group. There were no systemic reactions, although local skin reactions (generally of mild or moderate severity) were common, particularly in the 5% imiquimod cream group. Local reactions caused two patients to discontinue treatment. The most frequently reported local skin reactions were erythema, excoriation or flaking, and erosion. Patient-applied 5% imiquimod cream is effective for the treatment of external genital warts and has a favorable safety profile.

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

“…This dose relationship was also observed with respect to the proportion of subjects requiring a rest period. Imiquimod concentration has previously been shown to affect both safety and efficacy in studies of external genital warts, 22 but has not been previously evaluated with respect to treatment of AKs. Qualitatively, the AEs were mostly consistent with those reported previously with treatment of AKs and other cutaneous conditions with imiquimod 5% cream.…”

Activity of HspE7, a Novel Immunotherapy, in Patients with Anogenital Warts

“…10,11 Stressgen Biotechnologies created a novel fusion protein, HspE7, which consists of Hsp65 from Mycobacterium bovis variant bacille Calmette-Guerin covalently linked by a histidine residue to the N-terminus of the E7 oncoprotein of HPV-16. The fusion protein was designed to combine the immune stimulatory properties of Hsp65 with an appropriate target antigen from HPV.…”

Imiquimod: A Review

“…Studies have shown that topical application of imiquimod induces local cytokine production and reduces HPV load in patients with external genital warts. 13 When imiquimod 5% is used 3 times a week for 16 weeks the clearance rate in immunocompetent patients ranges from 35% to 61.8% [13][14][15][16][17][18][19][20] (Table I), though it may be lower in individuals with HIV. 21 These rates are comparable to those found with the use of topical therapies such as podophyllin, podofilox, cryotherapy, bichloroacetic acid, and trichloroacetic acid; however, recurrence rates are lower with imiquimod 5% than with these agents.…”

“…15 Some studies report higher clearance rates in female than in male patients. [15][16][17][18][19][20][21][22] This is probably because male patients tend to have warts on the completely keratinized skin of the penile shaft, whereas female patients generally have warts on the vulva, which is only partially keratinized and is moist. [18][19][20][21][22] Another possible explanation could be that anatomic differences alter the amount of time the drug is in contact with the lesion.…”