Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy condition characterized by an association of arthritis and psoriasis that can lead to progressive joint damage, disability, and reduced life expectancy (Rheumatol 2003;42:1460–8). A substantial proportion of patients have persistent inflammation. The extent of radiographic progression in patients with established PsA is comparable with that of RA patients when matched for age, sex, and disease duration (Rheumatol 2001;28:1041–4).

Historically, the decision to use a particular treatment modality for PsA has been mainly derived from the extrapolation of data from patients with RA. Results from the recent Infliximab Multinational Psoriatic Arthritis Controlled Trial (IMPACT), indicated that therapy with infliximab (IFX) 5 mg/kg significantly improved the signs and symptoms of arthritis, as well as reduced skin psoriasis, in patients with active PsA resistant to prior DMARD therapy (Arthritis Rheum 2005;52:1227–36).

Using data from the 54 week IMPACT 2 trial data, the authors assessed the effect of IFX 5mg/kg compared with a placebo on structural damage in 200 PsA patients. Radiographic data was obtained from hand and feet measurements at weeks 0, 24, and 54. Erosions and joint space narrowing were evaluated by the van der Heijde-Sharp method modified for PsA.

Radiographic data indicated that IFX was an effective inhibitor of radiographically documented progression of joint structural damage. At week 24, IFX-treated patients had significantly less radiographic damage than placebo patients (mean change in total van der Heijde-Sharp score = −0.70 ± 2.53 vs 0.82 ± 2.62, p<0.001). Twelve placebo-treated patients vs 3 patients in the IFX group had changes in the total van der Heijde-Sharp scores exceeding the the smallest detectable change at week 24 (p = 0.017). In patients continued on IFX through week 46, mean change was −0.94 vs 0.53 in patients who crossed over from placebo to IFX (p=0.001). These results indicate that IFX provides effective inhibition of radiographic progression in PsA patients as early as 24 weeks and continues to provide protection after 1 year of treatment.