Objectives: Tumour necrosis factor-alpha (TNF-α) blocking agents are very effective in controlling systemic inflammation and improving clinical assessments in ankylosing spondylitis (AS). In view of potential side effects and high costs of long-term treatment, our aim was to investigate whether dose reduction of TNF-α blocking agents is possible without loss of effectiveness in AS patients in daily clinical practice.
Methods: Patients from the prospective observational GLAS cohort, fulfilling the modified New York criteria for AS, with active disease before start of TNF-α blocking therapy and stable (≥6 months) low disease activity on the conventional dose regimen, who started with dose reduction of TNF-α blocking therapy before June 2011 were studied. Dose reduction was patient-tailored (step-by-step approach) and consisted of lowering the dose and/or extending the interval between doses.
Results: Between June 2005 and March 2011, 58 AS patients started dose reduction of etanercept (n=39), infliximab (n=10), or adalimumab (n=9). Of all patients, 74%, 62%, and 53% maintained their reduced dose or dosing frequency after 6, 12, and 24 months, respectively. The mean dose of TNF-α blocking therapy over time corresponded to 62% of the standard dose regimen. Disease activity remained low in the majority of patients who maintained dose reduction after 24 months (94% had BASDAI<4). If there was recurrence of disease symptoms, patients achieved good clinical response after returning to the conventional regimen (88% reached BASDAI<4).
Conclusions: In this observational cohort, patient-tailored dose reduction of TNF-α blocking agents was successful preserving stable low disease activity over 24 months in approximately half of the AS patients.