This is a not interventional, pragmatic, prospective, randomized (cluster) study to evaluate the potential benefit of a Treat to Target approach in comparison to routine treatment (i.e. usual care) in patients with axial spondyloarthritis.

This study is reflecting the usual care either in accordance to the treating rheumatologist (arm: usual care) or in accordance to the international scientific recommendations (arm: T2T)

The tight control means that as soon as a treatment is initiated in a patient, the time permitting to evaluate its potential efficacy/safety has to be determined. In terms of safety, such time frame can be very short based on the occurrence of adverse events. In terms of efficacy it is usually recommended to evaluate an NSAIDs after 2 to 4 weeks of treatment intake and the TNF blockers after 12 to 16 weeks.

The Treat to Target means that there is an a priori decision of the target to reach while initiating a treatment and more importantly an a priori decision to intensify the treatment in case such target is not achieved.

There will be 2 arms in the study (tight control and treat to target arm and usual care arm).

160 patients (80 patients per arm) will be included during one year by 18 centers (10 in France, 4 in Belgium and 4 in Netherlands). Patients will be followed during 1 year.

Inclusion Criteria:

• Adults (between 18 and 65 years old)

• With a diagnosis of axial spondyloarthritis according to the axial ASAS criteria AND the opinion of the treating rheumatologist.

• Active disease defined as an ASDAS ≥ 2.1

• Predominant axial disease meaning that:

  • Patients with non-spinal rheumatological symptoms and/or extra-rheumatological manifestations requiring at baseline the initiation of a specific treatment will be excluded.
  • Patients with a past history and/or a current well controlled non-spinal rheumatological or extra-rheumatological features will be eligible for the study.

• Non-optimally treated with NSAIDs (i.e. who have not received at least 2 NSAIDS, daily during at least 2 weeks at full dose, during the last year). Annex II summarizes the list of commonly used NSAIDs and the definition of a "full" use.

• With available pelvic X-rays, B27 and MRI of the sacro-iliac joints (performed at any time since symptoms onset)

• With no contraindication to the use of a NSAID

• With no intake of apremilast during the previous 3 months

• Able to understand the objectives of the study and to fill the questionnaires

• Written informed consent.

Patient with a diagnosis of predominant axial spondyloarthritis according to the axial ASAS criteria AND the opinion of the treating rheumatologist, and an active disease defined as an (ASDAS ≥ 2.1), and non-optimally treated with NSAIDs.