Interferon alpha for the treatment of melanocytic conjunctival lesions

To evaluate the effect of topical interferon alpha-2b therapy in the treatment of melanocytic conjunctival lesions. Non-comparative prospective case series. Nine patients with histologically proven acquired melanosis with atypia and/or conjunctival melanoma were treated with recombinant IFN alpha-2b (Intron A, Essex Pharma, Luzern, Switzerland). The agent was diluted under sterile conditions to one million international units per ml Intron A and packed in single-dose units (EDO) by the pharmacy. It was stored in the refrigerator and applied 5 x 1 drop/day topically by the patient for 6 weeks. The patients were seen after 2 weeks and after the end of the treatment. Endpoint of the treatment was the complete regression of pigmentation or absence of cytological atypia in a re-biopsy. Seven lesions of nine patients showed regression and lost pigmentation. Three patients required a second cycle after the first therapy because of incomplete regression and one patient needed a third cycle of interferon. Only one of the patients needed a fourth cycle of therapy and additional surgery to show stable regression. The follow-up is 24.8 months (median). No local or systemic side-effects were encountered. The pre- and post-treatment photos of two cases will be presented. Our observations suggest that topical interferon alpha-2b might be an effective agent for the adjuvant treatment of melanocytic conjunctival tumors without side-effects. It might be an alternative to other more toxic chemotherapeutical agents. A prospective multicenter study will help to finally evaluate the potential of topical interferon therapy for melanocytic conjunctival tumors, in particular PAM with atypia and minimal invasive conjunctival melanoma.