Interferons in the treatment of genital human papillomavirus infections.

Three major classes of interferons have been identified (alpha, beta, and gamma). All three have been tested in clinical trials in condylomata acuminata, or genital warts, with positive results. Administration by topical, intralesional, intramuscular, and subcutaneous routes results in regression of human papillomavirus genital disease. Significant reduction in measurable lesions occurs in some patients within days of initiation of therapy. Responses appear to be both time and dose dependent. Although disease resolution is highly variable from patient to patient, approximately 75 to 80 percent of all persons show clear clinical benefit at low doses. Biologic side effects of interferons are tolerated well at these doses and occur following systemic or local administration of interferon. In general, the interferons are emerging as active and safe therapeutic agents for genital human papillomavirus infections. This study reviews in detail the series of clinical trials conducted with one of these agents, interferon alpha n1. Results of four small and two major controlled trials in refractory genital warts have proved that this interferon provides significant clinical benefit for the majority of subjects with severe disease. Current studies show that it can be combined safely and effectively with other conventional treatment modalities, such as laser or podophyllin.