Therapeutic Targets for Ankylosing Spondylitis - Recent Insights and Future Prospects

Precision medicine in axial spondyloarthritis: current opportunities and future perspectives

Axial spondyloarthritis (axSpA) is a complex disease characterized by a diverse range of clinical presentations. The primary manifestation is inflammatory lower back pain, often accompanied by other clinical manifestations such as peripheral arthritis, enthesitis, uveitis, psoriasis, and inflammatory bowel disease. However, the presentation of axSpA can vary widely among patients. Despite extensive research, the precise pathogenesis of axSpA remains largely unknown. The lack of complete understanding poses challenges in subgrouping the disease, developing specific treatment approaches, and predicting treatment response. In this review, we will explore the limitations in diagnosing and treating axSpA. In addition, we will examine the current knowledge and potential opportunities provided by various omics and technological advancements in enhancing the diagnosis and personalized treatment of axSpA.

A strategy towards disentangling treatment refractory from misdiagnosed axial Spondyloarthritis

Axial spondyloarthritis (axSpA) encompasses radiographic axial SpA (r-axSpA), formally designated as ankylosing spondylitis (AS) and non-radiographic axial SpA (nr-axSpA). The advent of MRI permitted the description of the "pre-radiographic" (nr-AxSpA) stage characterized by bone marrow oedema lesions, histologically an osteitis, not yet visible on X-rays. Most subjects with a diagnosis of nr-axSpA do not progress to r-axSpA and the risk of misdiagnosis of nr-axSpA is considerable because back pain related to malalignment, degenerative conditions or biomechanical stress including intense exercise may lead to positive MRI scans. Even when nr-axSpA or r-axSpA are accurately diagnosed only about 40-50% achieve the ASAS40 responses with licensed therapies. It is likely that spinal enthesitis/osteitis leading to structural damage and associated damage contributes to post inflammatory disc territory secondary pain responses. Things are complicated as the concept of refractory axSpA itself is not well defined since there is no gold standard test to capture the full burden of inflammatory disease and, in any event, MRI has not been systematically applied. Nevertheless, there is sufficient evidence to borrow from the refractory rheumatoid arthritis field to propose two types of refractory axial SpA- a persistent inflammatory refractory ax-SpA (PIRaxSpA) and non-inflammatory refractory ax-SpA (NIRaxSpA). Both axSpA refractoriness and misdiagnosis need careful considerations when evaluating treatment failure. The immunological basis for axSpA immunotherapeutics non-responses is still rudimentary beyond the knowledge of HLA-B27 positivity status, CRP elevation, and MRI bone oedema that represents osteitis being equated with responder status.

Risk of candidiasis associated with interleukin-17 inhibitors: Implications and management

The application of interleukin-17 (IL-17) inhibitors, including secukinumab, ixekizumab, brodalumab, and bimekizumab, are associated with elevated risk of candidiasis. These medications interfere with the IL-17 pathway, which is essential for maintaining mucosal barriers and coordinating the immune response against Candida species. The observational data and clinical trials demonstrate the increased incidence of candidiasis in individuals treated with IL-17 inhibitors. Brodalumab and bimekizumab pose a greater risk than secukinumab in eliciting candidiasis, whereas the data regarding ixekizumab are equivocal. Higher doses and prolonged treatment duration of IL-17 inhibitors increase the risk of candidiasis by compromising the immune response against Candida species. Prior to prescribing IL-17 inhibitors, healthcare professionals should comprehensively evaluate patients' medical histories and assess their risk factors. Patients should be educated on the signs and symptoms of candidiasis to facilitate early detection and intervention. Future research should focus on identifying the risk factors associated with candidiasis in patients receiving IL-17 inhibitors. Prospective studies and long-term surveillance are required to explore the impact of specific inhibitors on the incidence and severity of candidiasis and to evaluate the effectiveness of combination therapies, such as concurrent use of IL-17 inhibitors and prophylactic antifungal agents.

Updates on ankylosing spondylitis: pathogenesis and therapeutic agents

Ankylosing spondylitis (AS) is an autoinflammatory disease that manifests with the unique feature of enthesitis. Gut microbiota, HLA-B*27, and biomechanical stress mutually influence and interact resulting in setting off a flame of inflammation. In the HLA-B*27 positive group, dysbiosis in the gut environment disrupts the barrier to exogenous bacteria or viruses. Additionally, biomechanical stress induces inflammation through enthesial resident or gut-origin immune cells. On this basis, innate and adaptive immunity can propagate inflammation and lead to chronic disease. Finally, bone homeostasis is regulated by cytokines, by which the inflamed region is substituted into new bone. Agents that block cytokines are constantly being developed to provide diverse therapeutic options for preventing the progression of inflammation. In addition, some antibodies have been shown to distinguish disease selectively, which support the involvement of autoimmune immunity in AS. In this review, we critically analyze the complexity and uniqueness of the pathogenesis with updates on the findings of immunity and provide new information about biologics and biomarkers.

Challenges in treating juvenile idiopathic arthritis

PURPOSE OF REVIEW

Juvenile idiopathic arthritis (JIA) diagnosis and classification is currently still based on clinical presentation and general laboratory tests. Some joints such as the temporomandibular joint (TMJ) and sacroiliac (SI) are hard to assess and define as actively inflamed based on clinical examination. This review addresses these difficult to assess joints and provides the latest evidence for diagnosis and treatment.

RECENT FINDINGS

Recommendations on clinical examination and radiological examination are available. Recent 2021 ACR recommendations were made for TMJ arthritis and in 2019 for sacroiliitis.

SUMMARY

New evidence to guide clinical suspicion and need for further investigations are available for these hard to assess joints. These guidelines will help healthcare providers in diagnosis and treatment assessment.