Abstract: Objective: To assess the efficacy of long-term treatment with infliximab in the patients with psoriasis arthropathica. Methods: Patients diagnosed as psoriasis arthropathica who treated with infliximab in our hospital from November 2016 to November 2018 were followed up and analyzed. The improvement of joint symptoms, PASI and the changes of TNF-α level were evaluated before treatment and after treatment at  week 2 , week 6, and then once every 8 weeks. Results: The data of eight patients received the treatment of infliximab for at least 30 weeks was analyzed, of those five treated for more than 46 weeks. LSD method showed that the number of swollen joints (before treatment VS week 30: t=6.939, P<0.001; before treatment VS week 46: t=3.822, P=0.019) and tenderness joints (before treatment VS week 30: t=5.353, P=0.001; before treatment VS week 46: t=3.132, P=0.035) significantly decreased after treatment, and the PASI score reached the lowest level at week 30 (before treatment VS week 30: t=3.742, P=0.007), while plasma TNF-α increased within first 22 weeks (before treatment VS week 22: t=3.569, P=0.009) and then decreased afterwards (week 30 VS week 46: t=4.104, P=0.009). Conclusion: Infliximab can significantly improve articular symptoms and skin lesions in patients with psoriasis arthropathica. However, the drug efficacy showed a declining trend in a long-term treatment.

Key words: psoriasis arthropathica, biological agents, infliximab