Treatment of refractory inflammatory monoarthritis in ankylosing spondylitis by intraarticular injection of infliximab

Objective. We describe a series of cases to evaluate the effect of intraarticular infliximab in patients with ankylosing spondylitis (AS) with treatment-resistant arthritis, and to consider whether longterm treatment with intravenous infliximab could be avoided in these patients. Methods. Three patients, fulfilling the New York criteria for AS, had relapsing arthritis of the knee, despite nonsteroidal antiinflammatory drugs, sulfasalazine, and multiple intruarticular (IA) injections of corticosteroids. Since the axial disease or other locomotor manifestations did not justify administration of systemic tumor necrosis factor-alpha (TNF-alpha) blocking agents, an IA injection of 100 mg infliximab was administered. The primary endpoint was to examine the efficacy and safety of IA injection of infliximab in AS patients with therapy-refractory arthritis. Before and 4 weeks after IA injection the following variables were evaluated: degree of swelling and tenderness of the affected joint, number of cells/mm(3) after joint fluid examination, Bath Ankylosing Spondylitis Disease Activity Index, erythrocyte sedimentation rate, and C-reactive protein. In all 3 cases magnetic resonance imaging (MRI) was performed before injection and 4 weeks after injection. Results. Clinical and biological variables and the MRI findings clearly improved. Remission of the peripheral arthritis was maintained up to 4 months in the first patient and up to 3 months in both others. No important side effects were noted. Conclusion. We observed a beneficial effect of IA infliximab in refractory arthritis in patients with AS. This procedure could be considered an effective and safe treatment for therapy of refractory monoarthritis in AS and an alternative for parenteral TNF-blocking therapy.