Spondyloarthropathy in Inflammatory Bowel Disease: From Pathophysiology to Pharmacological Targets

Spondyloarthritis (SpA) represents one of the most frequent extraintestinal manifestations of inflammatory bowel disease (IBD). Evidence of shared genetic and molecular pathways underlying both diseases is emerging, which has led to rational approaches when treating patients with concomitant diseases. Clinical efficacy of tumor necrosis factor (TNF) antagonists has been ascertained over the years, and they currently represent the cornerstone of treatment in patients with IBD and SpA, but the therapeutic armamentarium in these cases has been recently expanded. Evidence for vedolizumab is controversial, as it was associated both with improvement and development of arthralgias, while ustekinumab, the first anti-interleukin 12/23 (IL-12/23) approved for IBD, has demonstrated good efficacy, especially in peripheral arthritis, and more IL-23 inhibitors are being developed in IBD. Tofacitinib was the first Janus kinase (JAK) inhibitor to be approved in IBD, and as it demonstrated efficacy in treating ankylosing spondylitis, it may represent a good choice in axial arthritis, while more selective JAK inhibitors are yet to be approved. Unexpectedly, the first anti-IL17 that was studied in IBD (secukinumab) has shown not to be effective in treating IBD, and the role of anti-IL17 drugs in these diseases needs further investigation. Therefore, as availability of biologics and small molecules is increasing, their positioning in clinical practice is becoming more and more challenging, and multidisciplinary management needs to be implemented in both research and clinical settings in order to enhance early recognition of SpA in IBD patients, optimize treatment and ultimately improve the patients' quality of life.