World Ankylosing Spondylitis Day 2026: Closing the Diagnosis Gap and Advancing Treatment Options

World Ankylosing Spondylitis (AS) Day is observed annually on the first Saturday of May (unless it falls on May 1st) to raise awareness of ankylosing spondylitis, a chronic inflammatory disease that primarily affects the spine and sacroiliac (hip) joints.

Spondyloarthritis (SpA) is an umbrella term for a group of related inflammatory diseases that share key clinical features, most notably arthritis affecting the spine and other joints. The conditions typically emerge early in life, with symptoms most often beginning before the age of 45.

Clinically, SpA is broadly divided into two overlapping categories: axial spondyloarthritis (axSpA), which primarily involves inflammatory back pain and arthritis of the spine and sacroiliac joints, often extending to the hips; and peripheral spondyloarthritis (pSpA), which is characterized by inflammation in joints outside the spine as well as in tendons and entheses, affecting areas such as the knees, ankles, shoulders and elbows.

Ankylosing spondylitis is a form of axSpA characterized by inflammation in the spine that can lead to chronic pain, stiffness and in advanced cases, fusion of the vertebrae, sometimes resulting in a forward-stooped posture. While the condition is often associated with back pain, it can also affect the eyes, heart, lungs and other joints.

Over time, the inflammation can cause changes in bones such as ankylosis, which is the stiffening, rigidity or fusion of bones and joints, often resulting from chronic inflammation. In ankylosing spondylitis, inflammation can cause vertebrae to fuse, reducing spinal flexibility and potentially leading to a hunched posture. If the joints in the chest are involved, breathing deeply may become more difficult.

There are two types of axSpA: when the condition is found on X-ray, it is called radiographic axSpA (ankylosing spondylitis), and when it isn’t visible on X-ray but is found based on symptoms, blood tests and other imaging tests, such as an MRI, it is called nonradiographic axSpA.

Many patients experience a combination of both axial and peripheral symptoms. In practice, the dominant pattern of involvement, whether spinal (axial) or limb/joint-based (peripheral), guides classification and helps determine the most appropriate diagnosis and treatment approach.

In the US, more than 3.2 million adults are estimated to be living with some form of SpA, making it more prevalent than rheumatoid arthritis, multiple sclerosis and amyotrophic lateral sclerosis (ALS) combined.

World Ankylosing Spondylitis Day focuses on promoting early diagnosis, highlighting patient challenges and encouraging movement, as well as encouraging global solidarity for those living with the disease.

Ankylosing Spondylitis: Early Diagnosis Challenges

One of the biggest challenges with ankylosing spondylitis is delayed diagnosis. Symptoms often begin in late adolescence or early adulthood and may be mistaken for more common causes of back pain, such as mechanical strain or injury.

On average, diagnosis can take several years, which delays access to treatments that can significantly slow disease progression and improve quality of life.

Awareness campaigns tied to World Ankylosing Spondylitis Day aim to shorten this diagnostic gap by educating both the public and healthcare providers about early warning signs, including persistent back pain that improves with movement but not rest, morning stiffness and reduced spinal mobility. Chronic pain and fatigue can significantly affect mental health, work productivity and social well-being.

Many individuals with ankylosing spondylitis face invisible disability, where their condition is not outwardly apparent, leading to misunderstanding or minimization of their experiences. Advocacy efforts aim to foster empathy, reduce stigma and promote workplace accommodations that support those living with chronic inflammatory disease.

The exact cause of ankylosing spondylitis is not fully understood, but genetics play a strong role. The strongest link is the human leukocyte antigen-B27 (HLA-B27) gene, found in over 90% of white northern Europeans with the condition. However, having the gene does not guarantee developing the disease, as many people with it never develop it. Environmental triggers and immune system dysregulation are also believed to contribute.

While there is currently no cure, treatment options have advanced significantly. Nonsteroidal anti-inflammatory drugs (NSAIDs) are often first-line therapies to manage pain and stiffness. In more severe cases, biologic medications that target specific inflammatory pathways, such as tumor necrosis factor (TNF) inhibitors or interleukin-17 (IL-17) inhibitors, can dramatically reduce symptoms and slow progression.

Equally important is physical activity, including regular exercise, stretching and posture-focused physiotherapy, which are considered essential components of long-term disease management.

Current and Emerging Therapies in Ankylosing Spondylitis

The treatment landscape for ankylosing spondylitis has expanded considerably over the past two decades, evolving from broadly acting anti-inflammatory drugs to a more targeted, mechanism-based therapeutic environment.

Today, the market is primarily shaped by three major drug classes: TNF inhibitors, IL-17 inhibitors and Janus kinase (JAK) inhibitors.

TNF inhibitors were the first biologic agents to demonstrate meaningful disease modification in ankylosing spondylitis and remain widely used as first-line biologic therapy. These agents target TNF-alpha, a key inflammatory cytokine involved in the disease process. Drugs in this class include AbbVie’s blockbuster Humira (adalimumab), Amgen/Pfizer’s Enbrel (etanercept), J&J/Janssen’s Remicade (infliximab), Janssen’s Simponi (golimumab) and UCB Pharma’s Cimzia (certolizumab pegol).

Humira has generated over $200 billion in global revenue since its approval in 2002, making it one of the highest-selling pharmaceutical products in history. The drug maintained a 20-year monopoly for manufacturer AbbVie, reaching peak annual sales of nearly $20 billion before facing biosimilar competition in 2023.

While highly effective for many patients, a significant proportion either fail to respond adequately or lose response to TNF inhibitors over time.

This unmet need has driven the development and rapid adoption of IL-17 inhibitors, which represent the next major advance in biologic therapy for the condition. Novartis’ Cosentyx (secukinumab) was the first IL-17A inhibitor approved for ankylosing spondylitis (approved in 2016 by the FDA and 2015 in Europe) and established the class as a key treatment option. It was later joined by Eli Lilly with Taltz (ixekizumab), which also targets IL-17A and has demonstrated strong efficacy in axial symptoms.

More recently, UCB Pharma’s Bimzelx (bimekizumab), approved in 2024 for the treatment of ankylosing spondylitis, introduced a dual mechanism of action by inhibiting both IL-17A and IL-17F. At the same time as its approval for ankylosing spondylitis, it was also approved for psoriatic arthritis and non-radiographic axSpA, making it the first and only IL-17A and IL-17F inhibitor approved in the US for the treatment of four chronic immune-mediated inflammatory diseases, according to the company.

Alongside biologic therapies, oral JAK inhibitors have added a new dimension to treatment options for ankylosing spondylitis. Pfizer’s Xeljanz (tofacitinib) was one of the first JAK inhibitors evaluated in this setting, offering an oral alternative to injectable biologics.

More recently, AbbVie’s Rinvoq (upadacitinib), a selective JAK1 inhibitor, has emerged as a particularly important therapy in axSpA due to its once-daily oral dosing and strong clinical efficacy in patients who have had an inadequate response to biologics, including TNF alpha. Rinvoq’s global net revenues in 2025 totaled $8.30 billion. The drug is also approved for the treatment of several other immune-mediated diseases, including eczema (atopic dermatitis), rheumatoid arthritis, psoriatic arthritis, inflammatory bowel disease (IBD), Crohn’s disease, ulcerative colitis (UC) and giant cell arteritis.

The pipeline for ankylosing spondylitis is increasingly focused on improving precision, selectivity and patient convenience. Pharmaceutical companies are actively exploring next-generation IL-17 inhibitors and additional dual-target strategies that build on the success of drugs like bimekizumab.

At the same time, there is growing interest in targeting upstream inflammatory pathways such as IL-23, although results in axial disease have been less consistent than in other inflammatory conditions like psoriasis and IBD. Several IL-23 inhibitors, including guselkumab (Janssen), risankizumab (AbbVie) and mirikizumab (Eli Lilly), are under investigation in axSpA populations, though they have not yet established a clear role in ankylosing spondylitis.

In parallel, the JAK inhibitor class continues to expand, with newer molecules designed to offer greater selectivity for specific JAK pathways such as JAK1 or TYK2. Next-generation agents aim to maintain strong anti-inflammatory effects while improving safety profiles, particularly with respect to infection risk and metabolic side effects that have been associated with broader JAK inhibition.

Jiangsu Hengrui Pharmaceuticals’ ivarmacitinib (SHR0302) is emerging as a promising, highly selective JAK1 inhibitor in late-stage trials.