TNF, IL-17 inhibitors work equally regardless of MRI, CRP tests: Study

MRI or CRP testing may not help with treatment decisions, meta-analysis finds

Margarida Maia PhD avatar

by Margarida Maia PhD |

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People with axial spondyloarthritis (axSpA) respond equally well to two types of medications that ease inflammation — tumor necrosis factor (TNF) inhibitors or interleukin-17 (IL-17) inhibitors — regardless of their imaging findings or C-reactive protein (CRP) levels before treatment, a meta-analysis has found.

This suggests that neither magnetic resonance imaging (MRI) nor blood testing for CRP, a protein produced by the liver in response to inflammation, may help doctors make more informed decisions about which treatment is likely to be most effective for a particular patient.

The study, “Effect of Biologics in Subgroups of Axial Spondyloarthritis Based on Magnetic Resonance Imaging and C-Reactive Protein: A Systematic Review and Meta-Analysis,” was published as a brief report in ACR Open Rheumatology.

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Doctors currently use ‘trial and error’ approach for axSpA treatment

AxSpA occurs when the joints of the spine become inflamed, causing back pain and stiffness, along with swelling and fatigue. Some medications are available that may help ease these symptoms.

However, there are no objective indicators that can help predict how a patient will respond to a specific medication, so doctors “currently rely on a ‘trial and error’ approach for treatment,” the researchers wrote.

This means that doctors often try different medications for patients and observe how they respond over time. This process can be time-consuming and may not lead to optimal outcomes for all patients.

Identifying biomarkers could lead to a more personalized approach, moving away from trial and error. Now, researchers in the U.S. investigated whether MRI findings and blood CRP levels may be used as biomarkers.

The team searched the literature for Phase 2 or 3 randomized controlled trials and identified five studies where MRI findings and blood CRP levels were available before the start of treatment with TNF or IL-17 inhibitors.

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Meta-analysis included more than 1,500 patients from 5 trials

Three studies with a total of 729 patients — GO-AHEAD (NCT01453725), EMBARK (NCT01258738), and C-axSpAnd (NCT02552212) — tested the TNF inhibitors Simponi (golimumab), Enbrel (etanercept), and Cimzia (certolizumab pegol), respectively.

Two studies focused on IL-17 inhibitors, which also reduce inflammation: COAST-X (NCT02757352) tested Taltz (ixekizumab), whereas PREVENT (NCT02696031) tested Cosentyx (secukinumab). These two studies combined included 794 patients.

All five studies used a placebo as a control, and included adult patients who had non-radiological AxSpA, which means that damage caused by inflammation could not be seen on an X-ray, and they were followed for 12 to 16 weeks, or about 3 to 4 months.

In each study, the researchers created four distinct subgroups of patients based on the presence or absence of inflammation and damage on MRI of the sacroiliac joint, which connects the spine and hips, and higher-than-normal blood CRP levels.

All biologic therapies tested showed efficacy versus a placebo based on the Assessment of Spondyloarthritis International Society 40 (ASAS40), a measure of pain, inflammation, physical function, and overall well-being.

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No significant difference observed between 4 subgroups of patients

There was no significant difference between the four subgroups in terms of the proportion of patients who achieved an improvement, or no worsening, in their ASAS40 scores.

Similar observations were made when looking at data from Bath Ankylosing Spondylitis Disease Activity Index 50 (BASDAI50), a measure of disease activity.

“There was no statistically significant difference between the four subgroups in terms of efficacy based on ASAS40 or BASDAI50,” the researchers wrote.

There also were no differences between TNF and IL-17 inhibitors in terms of efficacy.

“Treatments were effective regardless of MRI and CRP positivity,” the team concluded. “Future studies should investigate the association of the degree of MRI inflammation … and CRP elevation with treatment response in axSpA.”