Two-year efficacy and safety of infliximab treatment in patients with active psoriatic arthritis: findings of the Infliximab Multinational Psoriatic Arthritis Controlled Trial (IMPACT).

OBJECTIVE: To investigate longterm efficacy/safety of infliximab over 2 years in patients with active psoriatic arthritis (PsA). METHODS: Initially, 104 patients were randomized to receive blinded infusions of infliximab 5 mg/kg or placebo at Weeks 0, 2, 6, and 14. At Week 16, all patients received infliximab 5 mg/kg every 8 weeks through Week 46. Seventy-eight of the 87 patients completing the first year continued into the open-label longterm extension and received infliximab 5 mg/kg at Weeks 54, 62, 70, 78, 86, and 94. The primary efficacy endpoint for the study extension was the proportion of patients with at least 20% improvement in the American College of Rheumatology response criteria (ACR20) at Week 98. Radiographic progression was assessed by the PsA-modified van der Heijde-Sharp score in patients with radiographs available at baseline and Week 98 (n = 43). RESULTS: At Week 98, 62% (48/78) of infliximab-treated patients achieved an ACR20 response; 45% (35/78) and 35% (27/78) of patients achieved ACR50 and ACR70 responses, respectively. Among patients with baseline Psoriasis Area and Severity Index scores >or= 2.5, 64% (16/25) achieved > 75% improvement from baseline to Week 98. The average estimated annual radiographic progression with infliximab treatment was significantly reduced versus the estimated baseline rate of progression. No new safety issues were observed during the second year of the study. CONCLUSION: Therapy with infliximab 5 mg/kg through Week 94 produced sustained improvement in joint and skin symptoms, inhibited radiographic progression, and continued to exhibit a favorable benefit-risk ratio in this population with treatment-refractory PsA.

Sustained benefits of infliximab therapy for dermatologic and articular manifestations of psoriatic arthritis: results from the infliximab multinational psoriatic arthritis controlled trial (IMPACT).

OBJECTIVE: To investigate the efficacy and tolerability of infliximab therapy for the articular and dermatologic manifestations of active psoriatic arthritis (PsA). METHODS: One hundred four patients with PsA in whom prior therapy with at least 1 disease-modifying antirheumatic drug (DMARD) had failed were recruited into this investigator-initiated, multicenter, randomized, double-blind, placebo-controlled clinical trial. During the initial blinded portion of the study, patients received infusions of infliximab (5 mg/kg) or placebo at weeks 0, 2, 6, and 14. After week 16, patients initially assigned to receive placebo crossed over to receive infliximab 5 mg/kg every 8 weeks through week 50, while patients initially randomized to infliximab continued to receive active treatment at the same dose through week 50. The primary efficacy outcome was achievement of the American College of Rheumatology 20% criteria for improvement in rheumatoid arthritis (ACR20) at week 16. Additional predefined clinical efficacy assessments included the Psoriasis Area and Severity Index (PASI) score, the ACR50 and ACR70 criteria, the Disease Activity Score in 28 joints, the Health Assessment Questionnaire, ratings of enthesitis and dactylitis, and the Psoriatic Arthritis Response Criteria score. RESULTS: The proportion of infliximab-treated patients who achieved an ACR20 response at week 16 (65%) was significantly higher than the proportion of placebo-treated patients who achieved this response (10%). In addition, 46% of infliximab-treated patients achieved an ACR50 response, and 29% achieved an ACR70 response; no placebo-treated patient achieved these end points. Among patients who had PASI scores of >/=2.5 at baseline, 68% of infliximab-treated patients achieved improvement of >/=75% in the PASI score at week 16 compared with none of the placebo-treated patients. Continued therapy with infliximab resulted in sustained improvement in articular and dermatologic manifestations of PsA through week 50. The incidence of adverse events was similar between the treatment groups. CONCLUSION: Therapy with infliximab at a dose of 5 mg/kg significantly improved the signs and symptoms of arthritis, psoriasis, dactylitis, and enthesitis in patients with active PsA that had been resistant to DMARD therapy. With continued infliximab treatment, benefits were sustained through 50 weeks. The benefit-to-risk ratio appeared favorable in this study population.