Purpose: To perform a prospective pilot study to evaluate interferon alfa-2a (IFN alfa-2a) for the treatment of refractory cystoid macular edema (CME) in endogenous uveitis.
Methods: IFN alfa-2a was administered at an initial dose of 3 or 6 million IU (depending on body weight) per day subcutaneously. Afterwards IFN alfa-2a was tapered slowly over 6 months and finally discontinued. If CME relapsed IFN alfa-2a was reinstituted and tapered slowly again to evaluate the lowest maintenance dose to keep remission.
Results: A total of 15 eyes of 8 patients with refractory CME due to intermediate or posterior uveitis were included. Ineffective pretreatment consisted of systemic steroids and acetazolamide (all patients) and at least one additional immunosuppressant (6 patients). Six of 8 patients (11 eyes) responded well to IFN alfa-2a and CME resolved completely during 6 months treatment. One patient was lost to follow-up after IFN alfa-2a was stopped. In 1 patient (1 eye) even 19 months after cessation of IFN alfa-2a no recurrence of CME occurred. In 4 patients (8 eyes) IFN alfa-2a had to be reinstituted because CME relapsed. All 4 patients responded again. During a mean follow-up period of 16.4 months since restart of therapy we succeeded in all 4 patients to taper IFN alfa-2a to maintenance doses between 1.5 million IU every second and every sixth day without a recurrence of CME in any of the 8 eyes.
Conclusion: IFN alfa-2a can be a treatment option for patients with otherwise treatment resistant uveitic CME.