Ankylosing Spondylitis Treatment Guidelines

Introduction to IL-17 Inhibitors

• The American College of Rheumatology recommends switching to an IL-17 inhibitor, such as secukinumab or ixekizumab, for patients with active ankylosing spondylitis who have failed both a TNF inhibitor and a JAK inhibitor 1, 2, 3

Rationale for IL-17 Inhibitor Over Second TNF Inhibitor

• The 2019 ACR/SAA/SPARTAN guidelines specifically recommend secukinumab or ixekizumab over a second TNF inhibitor in patients with primary non-response to the first TNF inhibitor, with a strength of evidence rated as high 1, 3
• Primary non-response is defined as absence of clinically meaningful improvement over 3-6 months after treatment initiation, which applies to patients who had no relief after 1 month on a TNF inhibitor, with a moderate strength of evidence 1, 2
• The guidelines explicitly recommend against switching to a biosimilar of the first TNF inhibitor in this scenario, with a high strength of evidence 1

Why Not Continue or Try Another JAK Inhibitor

• The guidelines rank TNF inhibitors, secukinumab, and ixekizumab as favored over tofacitinib for AS treatment, with a moderate strength of evidence 3
• One month may be insufficient to assess full response to a JAK inhibitor, but given the patient has active disease with no relief, continuing is not optimal, with a low strength of evidence 1, 2

Specific Medication Selection: Secukinumab vs Ixekizumab

• Both secukinumab and ixekizumab have demonstrated efficacy in AS with similar clinical response rates, with a high strength of evidence 3
• If the patient has comorbid inflammatory bowel disease, a TNF inhibitor monoclonal antibody would be preferred, with a moderate strength of evidence 4

Alternative Consideration: TNF Inhibitor Monoclonal Antibody

• Switch to a TNF inhibitor monoclonal antibody rather than another TNF receptor fusion protein, with a moderate strength of evidence 4

Common Pitfalls to Avoid

• Do not add methotrexate or other conventional synthetic DMARDs to biologic therapy for axial disease, as guidelines recommend against co-treatment, with a high strength of evidence 5, 6
• Do not prematurely discontinue or taper biologics once disease control is achieved, as 60-74% of patients relapse upon discontinuation, with a moderate strength of evidence 5, 6, 4

Monitoring and Follow-up

• Assess response to the new IL-17 inhibitor at 3-6 months using clinical measures of disease activity, with a moderate strength of evidence 1, 2
• Regular monitoring with CBC, CMP, and CRP every 3-4 months is recommended for patients receiving biologic therapy, with a low strength of evidence 4