Infliximab in psoriatic arthritis.

Tumor necrosis factor-α (TNF-α) plays a central role in the pathogenesis of psoriasis and psoriatic arthritis (PsA). Recently, 2 expert committees provided evidence-based recommendations for the treatment of PsA. Anti-TNF-α drugs are indicated in all forms of PsA resistant to traditional therapeutic approaches. Anti-TNF-α infliximab (IFX) is an immunoglobulin G-1 antibody that binds to soluble and cell membrane-bound TNF-α with its inactivation. Confirming previous open-label studies, 2 randomized, placebo-controlled clinical trials, IMPACT and IMPACT2, have provided evidence of the efficacy and safety of IFX in the treatment of PsA as evaluated by American College of Rheumatology (ACR)20, ACR50, and ACR70 response rates. At Week 16, a significant proportion of 51 IFX-treated patients achieved ACR20, ACR50, and ACR70 responses compared to the 51 patients of the placebo arm in the IMPACT trial. In the IMPACT2 study, 58% of the IFX-treated patients and 11% of placebo patients achieved an ACR20 response (p < 0.001), and 41% and 27% of patients in the IFX group were ACR50 and ACR70 responders, compared with 4% and 2% of placebo patients, respectively. Of note, a significant inhibition of radiographic disease progression was observed in the IFX-treated group. In both trials, psoriasis improvement was recorded in more than 80% of patients receiving IFX, with a significant difference compared to placebo group. IFX was well tolerated, with no difference compared to placebo in terms of adverse events. The extension phase of these studies showed the sustained efficacy and safety of the drug.