Long-term efficacy and safety of etanercept after readministration in patients with active ankylosing spondylitis

Abstract

Treatment of ankylosing spondylitis (AS) with the tumour necrosis factor alpha (TNF-alpha) receptor fusion protein etanercept has shown efficacy in patients with active disease in randomized controlled trials (RCTs) for limited periods. The objective of the study was to assess the long-term efficacy and safety of etanercept over 1 yr, including discontinuation and readministration. In this 54-week open observational study, 26 AS patients received 25 mg etanercept subcutaneously twice weekly after several months of discontinuation following a 6-month RCT with the same agent. All patients who developed high disease activity after cessation of etanercept, defined as a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) > or = 4 and pain > or = 4 on a numerical rating scale, entered the study. Standard assessment tools, such as the Bath Ankylosing Spondylitis functional index (BASFI), were used. An intention-to-treat (ITT) and a completer analysis were performed. The results were compared with the baseline values of the open study. Out of the initial 30 patients, 26 (87%) were eligible for the open extension study after a mean of about 27 weeks. At week 54, 23/26 patients (88%) were still on treatment with etanercept. The ITT analysis showed that 58% (95% confidence interval 39-74%) of the patients achieved a 50% improvement of BASDAI at week 54. According to the Assessments in Ankylosing Spondylitis working group criteria, 8/26 patients (31%) were in partial remission at week 54. Function, metrology and quality of life improved significantly. Only one patient had a serious adverse event that resulted in discontinuation. This study shows that treatment with etanercept is efficacious and safe after readministration over 1 yr in patients with active AS not taking DMARDs or steroids.