Human recombinant interferon alfa-2a for the treatment of Behçet's disease with sight threatening posterior or panuveitis

Abstract

Background: Behçet's disease is a multisystem vasculitis of unknown origin. Standard treatment mainly comprises systemic immunosuppressive agents. Ocular involvement, mostly posterior uveitis with retinal vasculitis, leads to blindness in 20-50% of the involved eyes within 5 years. The efficacy of interferon alfa-2a was studied in patients with sight threatening posterior uveitis or retinal vasculitis.

Methods: 50 patients were included in this open, non-randomised, uncontrolled prospective study. Recombinant human interferon alfa-2a (rhIFNalpha-2a) was applied at a dose of 6 million units subcutaneously daily. Dose reduction was performed according to a decision tree until discontinuation. Disease activity was evaluated every 2 weeks by the Behçet's disease activity scoring system and the uveitis scoring system.

Results: Response rate of the ocular manifestations was 92% (three non-responder, one incomplete response). Mean visual acuity rose significantly from 0.56 to 0.84 at week 24 (p<0.0001). Posterior uveitis score of the affected eyes fell by 46% every week (p<0.001). Remission of retinal inflammation was achieved by week 24. Mean Behçet's disease activity score fell from 5.8 to 3.3 at week 24 and further to 2.8 at week 52. After a mean observation period of 36.4 months (range 12-72), 20 patients (40%) are off treatment and disease free for 7-58 months (mean 29.5). In the other patients maintenance IFN dosage is three million units three times weekly.

Conclusions: rhIFNalpha-2a is effective in ocular Behçet's disease, leading to significant improvement of vision and complete remission of ocular vasculitis in the majority of the patients.

Figure 1

Flow chart for interferon dosage. In case of worsening after dose reduction return to last effective dosage.

Figure 2

Scoring sheet for posterior uveitits score (BenEzra et al40).

Figure 3

(A) Mean visual acuity by week of IFN treatment for the affected (thick line) and the unaffected (thin line) eyes. (B) Visual acuity of the affected right eyes at weeks 0 and 24 (n=35), thick line: mean. (C) Visual acuity of the affected left eyes at weeks 0 and 24 (n=37), thick line: mean.

Figure 4

Geometric mean of posterior uveitis score (PUS) by IFN treatment over time for affected eyes (thick line) and unaffected eyes (thin line).

Figure 5

Patient No 40 (A) before IFN treatment. Right eye, oedema of optic disc and macula, macular bleeding, neovascularisation of the optic disc, VA 0.2; (B) 6 months later, right eye VA 1.0, normal fundus.