To analyze the clinical response and the time to relapse after withdrawal of continuous long-term infliximab therapy in patients with ankylosing spondylitis (AS).
After 3 years of infliximab therapy, all AS patients (n = 42) discontinued treatment (TP1) and were visited regularly in order to assess the time to relapse (TP2) for 1 year. Relapse was defined as an increase to a Bath AS Disease Activity Index (BASDAI) value and physician's global assessment > 4 according to the ASAS recommendations.
After 52 weeks, 41 of the 42 patients (97.6%) had to be reinfused because of relapse. The mean change of the BASDAI between TP1 and TP2 was 3.6 ± 1.7, and for the physician's global assessment was 4.4 ± 1.8 (both P < 0.001). The mean time to relapse was 17.5 weeks (± 7.9 weeks, range 7–45 weeks). Ten patients (24%) showed a relapse within 12 weeks and 38 patients (90.5%) within 36 weeks. After 52 weeks, only one patient had remained in ongoing remission without anti-tumor necrosis factor therapy. Patients who were in partial remission and those with normal C-reactive protein levels at baseline had longer mean time to relapse after discontinuation. Retreatment with infliximab was safe and resulted in clinical improvement similar to the state before withdrawal in all patients.
Discontinuation of long-term therapy with infliximab led to relapse of disease activity in all but one patient after different time periods. Remission and low C-reactive protein levels at the time of withdrawal were associated with longer flare free periods. Retreatment with infliximab was safe and efficacious.