Brief summary: This study compares the long-term efficacy and safety of interferon (IFN) α2a and cyclosporine (cyclosporin A, CsA) following suppression of acute attack by high-dose oral glucocorticosteroid in patients with refractory Behçet's uveitis (BDU). Half of the participants will receive IFNα2a while the other half will receive CsA.

Detailed description: Both CsA and IFNα2a have been shown to be effective for long-term control of BDU, however, randomized prospective comparative studies are scarce, particularly in East Asian populations. Our preliminary data gave us the impression that IFNα2a might be more effectiveness than CsA in long-term control of refractory BDU, and this study aimed to compare their effectiveness and safety profiles in a well-designed prospective study. Refractory BDU is defined as relapse of posterior or pan- uveitis with at least 10mg daily prednisone (or equivalent) and one traditional immunomodulatory treatment (IMT) agents. The acute attack is controlled with large dose oral corticosteroid (60mg daily prednisone) for 4 weeks, and then the patients are randomly assigned to the IFN arm and the CsA arm, in which patients are treated with IFNα2a (3×10^6 IU qd for 4 weeks and qod thereafter) and CsA (100mg bid), respectively, along with a fixed tapering regimen of corticosteroid. Patients were followed up until relapse, or for 12 months.

Inclusion Criteria:

• Refractory BDU patients fulfilling the International Criteria for Behçet's disease (ICBD) published in 2013 with recent recurrence of pan- or posterior uveitis;
• The patient should be on ≥10mg/d oral prednisone or equivalent with at least one of the following IMT agents: cyclophosphamide≥50mg/d, CsA≥100mg/d, azathioprine≥50mg/d, methotrexate≥15mg/w, mycophenolate≥1000mg/d, tacrolimus≥2mg/d.

Exclusion Criteria:

• Previous treatment with interferon-α;
• Pregnancy, breast feeding women;
• Malignancy;
• Renal impairment (creatinine > 1.5 mg/dl);
• Uncontrolled hypertension or diabetes;
• Depression or other psychic disorders;
• History of acute or chronic inflammatory joint or autoimmune disease;
• Patients with severe extra-ocular involvement other than oral/genital ulcer and skin involvement;
• Organ or bone marrow transplant recipient, cardiac failure > NYHA III;
• Acute liver disease with ALT or SGPT 2x above normal;
• White blood cell count < 3500/mm^3;
• Platelet count < 100000/mm^3;
• Hgb < 8.5g/dl;
• T-SPOT TB: ≥200 SFCs per 10^6 PBMC;
• Active peptic ulcer, systemic or local infection, moderate to severe osteoporosis or other contraindications of large dose corticosteroids;
• Previous intolerance to CsA;
• Other severe ocular diseases or intraocular surgery within 3 months;
• Media opacity precluding a clear view of the fundus;
• Positive screen test for HBV, HCV, HIV infection or syphilis;
• Body weight <45 kg;
• Alcohol abuse or drug abuse;
• Mental impairment;
• Uncooperative attitude.

The individual participant data are available from the investigator upon reasonable request.