This small prospective trial found that interferon beta was superior to standard immunosuppressive treatment with methotrexate in patients with intermediate uveitis.
The findings of this study represent a shift in the therapeutic strategy for patients with intermediate uveitis. It is believed that interferons play a role in immunomodulation rather than immunosuppression. Patients with intermediate uveitis who develop macular edema may have multiple sclerosis, and interferon beta-1a has been used in the treatment of multiple sclerosis.
Immune-mediated uveitis usually is treated with nonspecific immunosuppression to prevent structural damage by inflammatory cells and cytokines. This study, however, has shown that immunomodulation may control the inflammation and macular edema. This therapeutic modality may also avoid the potential side effects of corticosteroids, including cataract and IOP elevation.
Subjects were 19 patients with either primary intermediate uveitis or uveitis associated with multiple sclerosis. They had visual acuity of 20/30 or worse (0.2 logMAR) and macular edema of more than 250 µm (central 1-mm in Stratus optical coherence tomography), and were resistant to treatment with systemic prednisone and acetazolamide given for four weeks.
They were randomized to receive either interferon beta 44 µg subcutaneously three times weekly or 20 mg methotrexate subcutaneously once weekly.
At three months, visual acuity improved by a mean 15.6 letters in the interferon beta group compared to 4.7 letters in the methotrexate arm (P = 0.0435). Macular thickness decreased by a mean of 206 µm in the interferon arm, but increased by 47 µm in the methotrexate group (P < 0.0001).
There was no change in the number of cells or vitreous haze in the methotrexate group, while there was improvement in the intraocular inflammatory activity in the interferon beta group. Furthermore, retinal sensitivity assessed using 10 degree visual field testing with fundus perimetry showed greater improvement in retinal sensitivity in the interferon beta group than the methotrexate group.