New advances in the understanding and treatment of axial spondyloarthritis: from chance to choice

Abstract

Axial spondyloarthritis (axSpA) is a chronic inflammatory condition that encompasses ankylosing spondylitis (AS) as well as non-radiographic axial disease (nr-axSpA) and can lead to chronic pain, structural damage and disability. The introduction of tumour necrosis factor inhibitor (TNFi) drugs for AS heralded a new era of drug therapeutics for what was previously a largely untreatable disease. This has now been expanded with the licensing of secukinumab, an interleukin 17A (IL-17A) inhibitor for the treatment of AS. Although biologic disease modifying antirheumatic drugs (bDMARDs) are not a first line treatment option in AS or axSpA, they are highly effective following incomplete or no response to physiotherapy and non-steroidal anti-inflammatory drugs (NSAIDs). Current research strategies aim to test whether the desired treatment goal of disease remission may now be achievable with early and stratified use of bDMARDs in both AS and nr-axSpA. This review summarizes the current literature on axSpA including pathophysiology, treatment indications, radiographic progression and the evidence for new developments in the treatment of both AS and nr-axSpA.

Keywords: IL-17A; JAK inhibitors; SpA; ankylosing spondylitis; anti-TNF; axSpA; axial psoriatic arthritis; biologic therapies; sacroiliitis; secukinumab.

Figure 1.

ASAS classification criteria for axial SpA in patients with back pain for at least 3 months and under 45 years of age. *Sacroiliitis is defined by definite radiographic evidence by modified New York criteria or on MRI by ASAS consensus definition. Adapted from Rudwaleit and colleagues. ASAS, Assessment of Spondyloarthritis International Society; MRI, magnetic resonance imaging; SpA, spondyloarthritis.

Figure 2.

ASAS40 and 20 responses to biologic DMARDs (bDMARDs) in ankylosing spondylitis (AS) and nonradiographic axial spondyloarthritis (nr-axSpA) in phase III clinical trials. Direct comparison is limited given that there are no head-to-head studies comparing biologics. Partly adapted from Sieper et al. DMARD, disease modifying antirheumatic drug.