Unmet Needs in Axial Spondyloarthritis

During the past decade, the well-known disease called ankylosing spondylitis has come to be considered as a subset of the broader entity referred as axial spondyloarthritis (axSpA), which also includes non-radiographic axSpA. The need of this new classification was aimed to improve the sensitivity for an early diagnosis, to reduce diagnostic delay, and to allow an early treatment. Although there is improvement in the recognition, the management of patients, and the treatment strategies of axSpA, unmet needs persist. There is still a substantial gap of 5–8 years between the onset of symptoms and the diagnosis of axSpA and, even in patients diagnosed early, 20–40% of them do not respond or have a loss of response to anti-TNF treatment. Moreover, the pathogenesis of the disease and, in particular, the mechanisms of new bone formation are far to be completely understood. Nevertheless, the discovery of IL-23/IL-17 axis with the development of biologic inhibitors, the identification of new subsets of effector cells, together with the interest in the detection of potential biomarkers of bone formation brought the approach to axSpA into a new era. This review is intended to enhance awareness and understanding of axSpA and to identify and discuss the current unmet needs in axSpA, including diagnosis, classification, biomarkers, pathogenesis, management, and treatment strategies.