Early response to adalimumab predicts long-term remission through 5 years of treatment in patients with ankylosing spondylitis

OBJECTIVES To describe the efficacy and safety through 5 years of adalimumab treatment in patients with ankylosing spondylitis (AS), and to identify predictors of remission. METHODS Patients with active AS were followed up to 5 years during a 24-week randomised, controlled period, followed by an open-label extension. Disease activity and clinical improvement were evaluated by Assessment in Spondyloarthritis International Society (ASAS) responses, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS). Kaplan-Meier was used to identify patients with sustained ASAS partial remission (PR) or ASDAS inactive disease (ID) for three or more consecutive visits spanning ≥ 6 months. Logistic regression was used to identify factors associated with remission. Explanatory variables included baseline demographic and disease characteristics and week 12 responses. RESULTS Of the 311 patients who received at least one dose of adalimumab, 202 (65%) completed the 5-year study. Among 125 patients who received 5 years of adalimumab, 70%, 77%, 51% and 61% achieved ASAS40, BASDAI 50, ASAS PR and ASDAS ID, respectively. Of 311 adalimumab-treated patients, 45% and 55% achieved sustained ASAS PR and ASDAS ID at any time during study participation. The strongest predictor of remission at years 1 and 5 and of sustained remission was achieving remission at 12 weeks of treatment; baseline characteristics showed weaker associations. Adverse events were comparable with previous reports on adalimumab safety. CONCLUSIONS In patients with active AS, the efficacy and safety of adalimumab were maintained through 5 years with about half of the patients experiencing sustained remission at any time during the study. Early achievement of remission was the best predictor of long-term and sustained remission.