Two Phase III studies evaluating imiquimod 3.75% and 2.5% creams as a treatment of external genital warts have shown that both are well-tolerated and more efficacious than a placebo.

In the Phase III programme, involving 981 patients with between two and 30 external genital warts, complete clearance of all warts in the per-protocol (PP) population was 33.8% for imiquimod 3.75% cream, compared to 11.5% for placebo cream.

Complete clearance of all warts in the intent-to-treat (ITT) population was 28.3% for imiquimod 3.75% cream, compared to 22.1% using 2.5% imiquimod cream and 9.4% for placebo cream.

The treatments were applied once daily for up to eight weeks.

The results also found that efficacy had been greater for imiquimod 3.75%, and all primary and secondary efficacy measurements were greater in women than men, in both the PP and ITT populations.

Treatment-related adverse events were also low. They included itching (2.5%), burning (5.8%) and pain (6.8%).

The study results will be reviewed by the US Food and Drug Administration.

External genital warts are caused by human papillomavirus, a sexually transmitted disease passed through genital contact.

Zyclara (imiquimod) Cream, 3.75% is marketed by UK-based pharmaceutical company Graceway Pharmaceuticals.