Topical and Subcutaneous Interferon-Alpha for the Treatment of Refractory Inflammatory Macular Edema

PURPOSE: To evaluate the efficacy of topical interferon alpha-2b (tIFN a2b) and subcutaneous pegylated interferon alpha-2a (peg-IFN a2a) in the treatment of refractory pseudophakic (PME) and uveitic (UME) macular edema. METHODS: Retrospective case series of patients with PME or UME that was non-responsive to conventional therapies. Topical IFN a2b drops (1 MIU/ml) were commenced four times a day. Non-responders were offered treatment with subcutaneous peg-IFN a2a starting at 180 mcg weekly. RESULTS: Seven eyes of seven patients (three UME and four PME) were treated with tIFN a2b. Three eyes had complete ME resolution with tIFN treatment after a mean of 2.66 weeks (range 1-4 weeks) and no recurrence after a mean total course of 11.33 weeks (range 5-20 weeks). Two cases (both PME) had partial responses to tIFN treatment and two cases (both UME) failed to respond. Of the four eyes that incompletely responded to tIFN (treatment range 6 weeks to 4 months), three were treated with peg-IFN a2a, which invariably led to complete and sustained ME resolution. Adverse effects from topical treatment were mild and consisted mainly of superficial irritation. Adverse effects of subcutaneous treatment included nausea, vomiting, anorexia, and leukopenia, though none limited treatment. CONCLUSIONS: Topical IFNa-2b appears safe and effective in isolation or in conjunction with topical steroids for the treatment of inflammatory macular edema (IME) in about half of patients in our small series. All partial and non-responders had complete disease resolution with systemic IFN. Topical IFN a2b should be considered in patients with refractory IME.