Mental Health, Education Among Factors Predicting Lack of Response to TNF-alpha Inhibitors in Axial Spondyloarthritis, Study Says

Poor mental health, not having a full-time job, spending fewer years in school, and having comorbidities such as hypertension or diabetes all contribute to failure to respond to initial treatment with TNF-alpha inhibitors among people with axial spondyloarthritis (axSpA), according to a real-world study.

The study, “Predicting response to anti-TNFα therapy among patients with axial spondyloarthritis (axSpA): results from BSRBR-AS,” was published in the journal Rheumatology.

axSpA is a type of arthritis that primarily affects the joints of the spine, causing chronic back pain. It is classified as ankylosing spondylitis if joint damage is visible through X-rays, or nr-axSpA if no damage can be seen.

Excessive levels of tumor necrosis factor (TNF), a molecule that drives inflammation, contribute to pain and swelling in people with axSpA. Inhibitors — such as Enbrel (etanercept), Humira (adalimumab), and infliximab (brand names Remsima, Remicade) — block TNF, and are common treatments in inflammatory disorders.

These therapies have improved function and quality of life for those with axSpA. However, studies that report benefits of TNF-alpha therapies typically average data across participants, overlooking people who do not respond to therapy or show limited improvement. Indeed, in a real-world setting, about 25% of patients with axSpA will no longer be on an a TNF-alpha inhibitor one year after starting treatment.

Obesity is one factor that has been linked with a lower likelihood of responding to TNF-alpha treatment. Researchers from Scotland and Canada used data from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS) — which includes patients from more than 80 clinical centers throughout Great Britain — to identify others, collecting socioeconomic, clinical, and patient-reported data.

The scientists assessed the proportion of patients meeting the Assessment in SpondyloArthritis International Society (ASAS) response, specifically ASAS 20 and ASAS 40, These are defined as improvement of at least 20% or 40% in a minimum of three of four categories — patient global assessment of disease, pain, function, and inflammation — with no more than 20% or 40% worsening in the other categories.

Changes in the composite Ankylosing Spondylitis Disease Activity Score (ASDAS) were also analyzed.

Overall, 335 people with a median age 46.6 years begain TNF-alpha therapy for the study, and were followed over a median of 14 weeks. None had received a biologic therapy prior to the study.

The proportion of patients responding to treatment ranged from 33% (with ASAS40) to 52% (with ASAS20).

Those who were not working full time and those who were less educated were less likely to respond to treatment, the study found. Having other conditions, such as hypertension, diabetes, or depression, and poor mental health were also associated with lack of response.

The outcome measures, particularly ASDAS, were good at predicting patients who did not respond to TNF inhibitors, the study found.

“Some factors predicting non-response [such as mental health] are modifiable, but many [such as social/economic factors] are not modifiable in clinic,” the researchers wrote. All factors, however, can help identify people who are unlikely to benefit from biologic therapy alone, they added.

“Priority should be focused on how we ensure that these patients receive the benefits that many patients derive from such therapies,” the researchers said.