Comparative Analysis of Two Therapeutic Strategies in Patients With Spondyloarthritis Treated With Anti-tnf Biologics

Comparative Analysis of Two Therapeutic Strategies: "Early Switch" Versus "Therapeutic Intensification" in Patients With Spondyloarthritis Treated With Anti-tnf Biologics, in Case of Secondary Treatment Failure Suspicion.

The objective of the study is to evaluate two therapeutic strategies: "early switch" or "therapeutic intensification" in patients with spondyloarthritis in case of secondary treatment failure suspicion to a first monoclonal antibodies anti-TNF definite by increase of ASDAS and positivity to ADAb.

Patients and Methods:

Multicentric randomized prospective study. Duration of inclusion 30 months. Duration of follow-up 24 months. 104 patients with spondyloarthritis treated with infliximab or adalimumab will be included if their ADAb dosage is positive, and they will be randomized (1:1) in two groups : "early switch" where treatment will be change to another anti-TNF, or "therapeutic intensification" where interval between two injections will be shortened. Patients will be evaluated clinically (ASDAS) and biologically (ADAb) at 12 weeks then at 24 weeks. Principal outcome will be the variation of ASDAS between baseline and end of the study. Number of patients to be included has been determined statistically from a preliminary study (power >98% for ASDAS variation of 20% on week 24).

Expected results:

On week 24, we expect a better response and a greater proportion of patients in remission in the "early switch" arm compare to the "therapeutic intensification" arm.

Inclusion Criteria:

• Spondyloarthritis positive for the ASAS criteria, treated with a first biologic : infliximab ( 5mg/kg intravenously every 8 weeks) or adalimumab (40mg subcutaneously every 2 weeks)
• Active spondyloarthritis definite by ASDAS-CRP > 2.1 at two successive evaluations while patient was previously responder (ASDAS<2.1 at least once in the 6th months after beginning of treatment)
• Positivity to anti-drug antibodies (ADAb)
• Consent of the patient
• No contra-indication to another anti-tnf biologic
• affiliation to health insurance
• woman of childbearing age must use an appropriate mean of contraception

Exclusion Criteria:

• Pregnant or breastfeeding woman
• contra-indication to anti-tnf biologic
• patient with known hypersensitivity to any of the excipients
• Severe and uncontrolled opportunistic infection , includins septicemia, tuberculosis, abcess and opportunistic infection
• Evolutive infection, including chronic or localised infection
• Patient with moderate to severe heart failure (NYHA class III/IV)