Objective: To evaluate the efficacy and safety of infliximab through one year in patients with psoriatic arthritis (PsA) enrolled in the IMPACT 2 trial.
Methods: In this double-blind, placebo- controlled, phase III study, 200 patients with active PsA were randomized to receive infusions of infliximab 5 mg/kg or placebo at Weeks 0, 2, and 6 and every 8 weeks thereafter through one year. Patients with persistent disease activity could enter early escape at Week 16, and all remaining placebo patients crossed over to infliximab at Week 24. Infliximab-randomized patients who had no response or who lost response could escalate their dose to 10 mg/kg starting at Week 38. Clinical efficacy was assessed based on the proportion of patients achieving ACR 20 and PASI 75 responses. Major clinical response (i.e., maintenance of ACR 70 response for 24 continuous weeks) was assessed for the first time in PsA.
Results: Through one year of treatment, 58.9% and 61.4% of patients in the randomized infliximab and placebo/infliximab groups, respectively, achieved ACR 20; corresponding figures for PASI 75 were 50.0% and 60.3%. At Week 54, major clinical response was achieved by 12.1% of patients in the infliximab group. The safety profile of infliximab through Week 54 was consistent with that observed through Week 24. Two malignancies occurred: basal cell skin cancer (placebo) and stage 1 Hodgkin's lymphoma (infliximab).
Conclusion: Infliximab maintains a high degree of clinical efficacy and continues to be well tolerated in patients with PsA through one year of treatment.
- ACR 20
- PASI 75
- psoriatic arthritis
- tumor necrosis factor alpha