Interferon alpha-n1 (Wellferon) for refractory genital warts: efficacy and tolerance of low dose systemic therapy.

This multi-center trial compared two doses of parenterally administered interferon alpha-n1 (Wellferon) in men and women with recurrent/resistant genital warts. Patients received either 1 or 3 MU/m2 daily for 14 days, then 3 times weekly for 4 weeks; non-responders could receive an additional four weeks of treatment. A total of 107 patients were enrolled, and 102 were evaluable after six weeks of study. The principal dose comparison was in 57 women assigned alternately to the two doses. Median lesion measurements were reduced significantly from baseline at weeks 2, 4 and 6 in both groups. Statistical analysis showed no difference in response to 1 versus 3 MU/m2. The overall complete response (CR) plus partial response (PR) rate at week 6 was 69% for the two doses. Two additional groups of 21 women and 24 men were treated at the higher dose with CR plus PR rates of 75 and 50%, respectively. Week 10 disease evaluations for all groups showed 19 of 77 patients to be completely cleared. Of these 19, only one had recurrent disease at the end of the 6-month study period. Analysis of the incidence of symptomatic side effects showed a significantly higher frequency among women treated with 3 MU/m2 than among women treated with 1 MU/m2. Five dose reductions and two withdrawals for toxicity occurred, all in the high dose group. This study demonstrates that parenterally administered Wellferon produces clearance of resistant genital warts in many patients, and that rates of clearance do not appear to vary between groups receiving moderate or low dose therapy.