Anogenital warts (condylomata acuminata) are difficult to treat successfully. The 0.5 percent podofilox solution is approved for self-use and, when used in three-day treatment cycles over a four-week period, appears to be less toxic than podophyllum resin. Previous studies have demonstrated a patient preference for self-treatment of genital warts. The gel was formulated as an easier-to-apply alternative. Tyring and associates performed a double-blind, randomized, vehicle-controlled study of podofilox gel in patients with anogenital warts.

A total of 292 immunocompetent patients were included in the study. The majority of the warts were located on the penile shaft in men and on the labia in women. Approximately 20 percent of the subjects had received previous treatment for warts. During the study period, participants were randomized to receive podofilox gel or vehicle gel. The topical medication was applied twice a day for three consecutive days, followed by four days without treatment (one cycle). Patients used the medication for two to eight treatment cycles.

The 0.5 percent podofilox gel was significantly more effective than vehicle gel for clearing anogenital and external genital warts after four weeks and eight weeks of treatment. Treatment success increased 31 percent (from 62 to 81 patients) with an additional four to eight weeks of podofilox gel therapy. No significant differences in clearance rates in men or women were apparent. Significantly fewer warts remained after active drug therapy. Physician assessment of response to treatment demonstrated that 73.8 percent of the patients treated with 0.5 percent podofilox gel had either moderate or marked improvement or complete clearing of warts after four weeks. At eight weeks, 81.1 percent of the patients treated with podofilox gel had either moderate or complete clearance of warts, compared with 17.2 percent of the patients treated with the vehicle gel. Significantly more patients discontinued treatment with the vehicle gel because of ineffective clearance of warts.

Adverse effects were significantly greater in the active drug group. The most common adverse events were burning, inflammation, itching, erosion, pain and bleeding. Burning was the most frequently reported side effect in the active drug group during the first six weeks. Almost all local adverse effects resolved within four weeks of cessation of treatment. The incidence of inflammation and erosion was significantly greater in men than in women. In women with external warts, the most common adverse event was burning (75.3 percent). For those with perianal warts, the most common local adverse events were burning in women (91.7 percent) and inflammation and pain in men (71.4 percent).

The authors conclude that 0.5 percent podofilox gel was significantly more effective than the vehicle gel in reducing numbers of genital warts (external and perianal) in both men and women. The gel form is easier to apply than the solution and does not have a higher adverse event profile.