The tumor necrosis factor alpha (TNF-α) receptor fusion protein etanercept has proven short-term efficacy in patients with active ankylosing spondylitis (AS). The results of continuous treatment with etanercept over 1 year were reported previously. Here we report the experience with the second year of follow-up.

Overall, 23 out of 30 AS patients (77%) who had participated in the initial placebo-controlled phase of the trial were included in this 2-year extension, where patients with active disease were treated with etanercept (2 × 25 mg subcutaneously twice a week). Disease-modifying anti-rheumatic drugs and steroids were not allowed. The clinical response was assessed by standard assessment tools for disease activity (Bath AS Disease Activity Index [BASDAI]), function (Bath AS Functional Index) and mobility (Bath AS Metrology Index). The primary outcome of this trial was efficacy on disease activity after 2 years of continuous treatment with etanercept in AS patients, compared with patient status at baseline (BL).

Of the 30 initial patients, 21 (70%) completed year 2. At week 102, 54% of the patients had maintained a 50% improvement of BASDAI, and 9/21 (43%) were in a state of partial remission according to the ASAS criteria. The mean BASDAI score remained stable (2.6 ± 2.2 at week 54 and 2.7 ± 2.4 at week 102) in the second study year. Similarly, all other clinical parameters showed no change during year 2 with significant improvement compared with BL. Two patients experienced serious adverse events leading to discontinuation of therapy.

This study confirms the efficacy and safety of etanercept in the therapy of patients with active AS without simultaneous administration of disease-modifying anti-rheumatic drugs or steroids over 2 years of continuous treatment.