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Characterizing the metabolic profiles of patients with rheumatoid arthritis (RA) via high resolution ¹H-nuclear magnetic resonance (NMR) may provide insight into patients’ potential response to tocilizumab therapy, according to new research released in conjunction with the American College of Rheumatology’s (ACR) annual meeting, ACR Convergence.

“Metabolomics may provide information about the activity and severity of specific diseases and potentially help discriminate between diseases,” the researchers wrote. “Choosing the right biological therapy earlier in the course of RA could help to reach the goal of remission.”

To assess whether ¹H-NMR could help predict response to tocilizumab therapy prior to treatment among patients with RA, the researchers studied data on 41 participants who had met the 2010 ACR/European League Against Rheumatism (EULAR) classification criteria and who had initiated treatment with tocilizumab, 8 mg/kg, every 4 weeks following usual clinical practice.

At baseline and again at 6 months after treatment, the participants’ clinical outcomes were recorded. Based on EULAR response criteria, the participants were categorized as responders (good response) or nonresponders (moderate response or no response). 

Also at the same 2 time points, NMR spectra of serum samples were collected. The researchers analyzed the relationship between metabolites and clinical outcomes. 

Overall, the participants had an initial Disease Activity Score 28 for RA with C-reactive protein (DAS28CRP) of 5.7±1.1. 

Both at baseline and 6 months after tocilizumab treatment, the ¹H-NMR baseline spectra were able to discriminate between participants classified as tocilizumab responders (n = 22) or nonresponders (n = 19).

According to a multivariate diagnostic model, concentrations of hydroxybutyrate, leucine, tryptophan, and alanine improved the sensitivity and specificity of the diagnosis, with an area under the curve of 92.7%. Using this biomarker model, 85% of the participants were correctly classified.

“The clear relationship between blood profiles and patient response to tocilizumab therapy suggests that the application of ¹H-NMR profiling is a promising clinical tool for RA therapy optimization,” the researchers concluded. “More metabolic profiles studies are needed to determine if metabolic profiling can predict response to other biological therapies in RA patients.”

—Colleen Murphy

Reference:

Murillo-Saich J, Diaz-Torne C, Angeles Ortiz M, et al. Metabolomics profiling predicts outcome of tocilizumab in rheumatoid arthritis. Study presented at: American College of Rheumatology Convergence 2020; November 5-9, 2020; Virtual. Accessed November 4, 2020. https://acrabstracts.org/abstract/metabolomics-profiling-predicts-outcome-of-tocilizumab-in-rheumatoid-arthritis/