[A multicenter, double-blind, randomized, placebo-controlled clinical trial of etanercept treatment of Chinese patients with active ankylosing spondylitis].

Objective: To evaluate the efficacy and safety of etanercept 50 mg once-weekly treatment of Chinese patients with active ankylosing spondylitis (AS).

Methods: Four hundred patients with active AS, enrolled in six medical centers, were randomly divided into either the treatment group or the placebo group in a 3:1 ratio. The total length of the study was 12 weeks. The first 6-week period was a double-blind placebo controlled treatment period and the second 6-week period was an open-labeled treatment period. During the first 6-week period, 300 patients in the treatment group received once-weekly subcutaneous injection of etanercept (50 mg), whereas the 100 patients in the placebo group received placebo injection. During the second 6-week period, patients in both groups received etanercept (50 mg once weekly subcutaneous injection). The primary end point was the percentage of patients achieving the Assessments in Ankylosing Spondylitis (ASAS) 20% response (ASAS 20) at week 6. Other outcome measures included the percentage of patients achieving ASAS 5/6, partial remission and Bath AS disease activity index 50 (BASDAI 50) responses at week 12.

Results: A total of 381 patients completed the trial, including 285 patients in the etanercept group and 96 patients in the placebo group. At week 2, the percentage of patients achieving ASAS 20 in the etanercept group was 55.7%, whereas the placebo group was only 17.0% (P < 0.001). At week 6, 77.5% of patients in the etanercept group achieved ASAS 20 as compared with 32.3% in the placebo group (P < 0.001). At the end of 12 weeks, the percentage of patients in the etanercept group achieving the ASAS 20 was 89.5%. Improvements of other measures were also significant in the etanercept group. Etanercept was well tolerated and no malignancy and life-threatening events were observed in this study. Most adverse events observed were mild injection-site reactions.

Conclusion: Etanercept 50 mg weekly treatment of Chinese patients with active ankylosing spondylitis is convenient, fast-acting, highly effective, and well tolerated.