Deciphering telltale signs, symptoms of non-radiographic axial SpA remains a challenge
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Given the limited awareness of non-radiographic axial spondyloarthritis, differentiating this disease from radiographic disease and prescribing appropriate therapy remains a key challenge, according to a presentation at the Biologic Therapies Summit.
“Epidemiological knowledge in the United States about this disease is limited,” Marina Magrey, MD, the rheumatology fellowship program director at MetroHealth in Cleveland, said of non-radiographic axSpA. “Up until recently, it did not have ICD-9 code.”
Patients with non-radiographic axSpA need to have either clinical evidence or imaging evidence for diagnosis. Clinical features may include uveitis, psoriasis, a family history of axial spondyloarthritis, inflammatory bowel disease (IBD), dactylitis, enthesitis or elevated C-reactive protein.
Patients generally have back pain for 3 or more months and are aged 45 years or younger, according to Magrey. Those who are diagnosed using imaging show evidence of sacroiliitis on MRI plus at least one of the aforementioned spondyloarthritis features.
Those who are diagnosed clinically are positive for the HLA-B27 mutation and have two of the spondyloarthritis features.
Clinicians should ask patients about the pattern of their back pain and other spondyloarthritis features. If the pain gets better with activity, non-radiographic axSpA should be considered. Skin rash is also commonly present, along with uveitis. “Uveitis is a low-hanging fruit,” Magrey said. “We can easily correlate this with axial disease.”
Family history is important, she added. If a patient meets these criteria and has a history of axial disease, the clinician should order HLA-B27 testing.
CRP levels are often lower in non-radiographic axSpA compared with radiographic disease.
In addition, patients have usually had a shorter disease duration at the time of diagnosis, despite frequent diagnostic delays. Radiographic damage is not as severe in non-radiographic axSpA compared with radiographic disease. Consequently, patients with radiographic disease often have lower spinal mobility, according to Magrey.
“It is more common in females than males,” she said. “Women don’t fuse the spine as often as men.”
Most cases of non-radiographic axSpA are diagnosed based on changes on MRI without contrast of the pelvis, which is the gold standard diagnostic approach, according to Magrey.
Magrey is often asked about which patients are likely to progress from non-radiographic to radiographic disease. “Several studies have tried to get an answer,” she said. “About 10% to 40% of patients progress over a period of 2 to 10 years. The probability of lifetime progression is 50%.”
Predictors of progression can range from high disease activity of CRP on MRI and HLA-B27 positivity to smoking and dactylitis.
Treatment paradigms for non-radiographic axSpA start with TNF-alpha and interleukin-17a inhibitors. Magrey suggested that TNF inhibitors adalimumab (Humira, Abbvie), certolizumab (Cimzia, UCB) and secukinumab (Cosentyx, Novartis) have shown long-term efficacy in this patient population. “They have all worked in axial disease,” she said. “We should not be surprised that they work in non-radiographic axSpA, since they are the same disease.”
The IL-17a blocker ixekizumab (Taltz, Eli Lilly & Co.) has met primary endpoints out to 52 weeks. Another drug in this class, bimekizumab (UCB), is moving into phase 3 trials. “I am hopeful that it is going to work in non-radiographic axSpA,” Magrey said.
In the janus kinase (JAK) inhibitor class, upadacitinib (Rinvoq, Abbvie) has shown “robust improvement” in this patient population, while tofacitinib has also yielded “significant improvement” in Ankylosing Spondylitis Disease Activity Score (ASDAS), according to Magrey.
If there is a key patient concern, it pertains to withdrawal or dose reduction. “If you stop treatment, there is a risk of the disease flaring,” Magrey said, putting this chance at roughly fifty-fifty.
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Magrey, M. What do we really know about non-radiographic spondyloarthropathy? Presented at: Biologic Therapies Summit IX; May 21-23, 2021 (virtual meeting).
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