Study Evaluating Predictors of Response in Patients With Ankylosing Spondylitis

Success and Failure of Biological Therapy: Predictors of Response in Patients With Active Ankylosing Spondylitis

The objective of this observational study is to determine the incidence of response in patients with predictive factors of major clinical response in active ankylosing spondylitis (AS) in patients who start anti-tumor necrosis factor (anti-TNF) therapy and correlate these findings in patients who switch from one to another anti-TNF due to inefficacy under usual clinical practice conditions in Spain.

A sample size of 240 patients, 120 of them exposed and 120 not exposed to factors of response. Sample will be obtain from all the consecutive patients attending the rheumatology settings included in the study who fulfill the inclusion criteria

Inclusion Criteria:

• Patients diagnosed of active AS who will start anti-TNF therapy following standard clinical practice as per summary of product characteristics doses.
• >18 years, both genders, any disease duration
• Signature of informed consent

Exclusion Criteria:

• Previous treatment with biological therapies
• Active tuberculosis infection (local guidelines for appropriate screening and treatment of tuberculosis in the setting of anti-TNF therapy must be followed)