Skip navigation

Imiquimod for genital warts

 

Clinical bottom line

With HIV-negative patients complete clearance of warts at the end of treatment occurred in 51% of patients treated with imiquimod 2% or 5% cream and 6% of placebo treated patients. The number needed to treat was 2.2 (95% confidence interval 2.0 to 2.6). For at least 50% wart area reduction the number needed to treat was 1.9 (1.7 to 2.2). For complete clearance of warts at the end of treatment plus no recurrence the number needed to treat was 3.0 (2.5 to 3.8). Adverse event withdrawal was rare and no more likely with imiquimod than with placebo. Imiquimod was not effective in one trial in HIV-positive patients.


Reference

RA Moore, JE Edwards, J Hopwood, D Hicks. Imiquimod for the treatment of genital warts: a quantitative systematic review. BMC Infectious Diseases 2001 1: 3. ( http://www.biomedcentral.com/1471-2334/1/3 ).

Review

Electronic databases were searched, together with reference lists and reviews for full publications of randomised trials of imiquimod for the treatment of genital warts, usually in comparison with placebo. The main outcomes sought were :

Results

Six studies were conducted in the setting of home administration after initial professional examination and advice. Five of the studies were explicit that no other treatment was allowed within at least four weeks of the start of the trial. Wart location was predominantly vulvar or perianal in women, and penile or perianal in men. Five studies were conducted in North America or the UK using 5% or 1% imiquimod cream (Aldara, 3M Pharmaceuticals), and one was conducted in Pakistan using a 2% cream manufactured locally.

Complete wart clearance

Complete clearance of warts was reported in all five trials of HIV negative patients. This was achieved in 51% of patients (45% to 56%) treated with the highest concentration of imiquimod (2% in one trial, 5% in four), but in only 6% (3% to 8%) of patients treated with placebo cream. The NNT was 2.2 (95% confidence interval 2.0 to 2.6). This means that two patients have to be treated with 2% or 5% imiquimod for 8 to 16 weeks for one of them to have warts completely cleared. The results for 5% imiquimod in four trials were similar.

At least 50% reduction in wart area

With imiquimod 5%, 72% (67% to 78%) of patients had the outcome, compared with 20% (15% to 25%) with placebo. The NNT was 1.9 (1.7 to 2.2). This means that two patients have to be treated with 5% imiquimod for 8 to 16 weeks for one of them to have wart area reduced by at least 50%.

Warts completely cured and not recurred

Warts were completely cured and did not recur in 37% (31% to 43%) of patients treated with imiquimod 5%, and 4% (2% to 6%) of patients treated with placebo. The NNT was 3.0 (2.5 to 3.8). This means that three patients have to be treated with 5% imiquimod for 8 to 16 weeks for one of them to have warts completely cleared, and for them not to recur.

Figure 1: Outcomes for highest concentration (usually 5%) imiquimod for three efficacy outcomes - blue with treatment and pink with placebo - in terms of percentage of patients achieving the outcome

Withdrawals because of treatment-related adverse events

There was no difference between imiquimod and placebo for treatment-related adverse event withdrawal.

Withdrawals because of lack of efficacy

There were significantly fewer withdrawals due to lack of efficacy with imiquimod 5% (1.7% than with placebo (7.4%).

Particular adverse events

Some local adverse events (itching, erythema, burning and erosion or excoriation) were reported with imiquimod. A temporary "holiday" from treatment usually resolved these problems.

Comment

This updates a previous Bandolier review looking at genital wart treatments. Many other treatments are available, including excision and local burning with, for instance, trichloroacetic acid. There are two choices for patients at home, imiquimod and podophyllotoxin. No review of the latter has yet been published (Aug 2001).