Prospective randomized trial of topical α-interferon (α-interferon gels) for the treatment of vulvar intraepithelial neoplasia III

Twenty-one patients were prospectively randomized into a blinded double-armed crossover study comparing α-interferon (α-IFN, 10⁶ IU in a 3.5% aqueous methycellulose base) with and without 1% nonoxynol-9. Nine and twelve patients were randomized to arms with (+N) and without (-N) 1% nonoxynol-9, respectively. Patients applied the gel to affected areas every 8 hr and were evaluated biweekly. Including those crossed over, 14 patients were treated with -N. Six of fourteen (43%) achieved complete responses: biopsy proven with at least 1 year follow-up (CR). One patient achieved a partial response with at least a 50% reduction in the total surface area of all lesions present (PR). Similarly, 13 patients were treated with +N. Two patients in this group were found to have invasive cancer and one to have HIV and thus were eliminated from statistical analysis. Of the remaining 10 patients, 3 had CRs (30%), 5 had PRs (50%), and 2 failed to respond. There was no significant difference in reponses between the two groups. Overall, 14 of 18 (67%) patients demonstrated some response to α-IFN applied topically. These data support the conclusion that α-IFN is an active agent in the treatment of vulvar intraepithelial neoplasia III.