Early changes in blood-based joint tissue destruction biomarkers are predictive of response to tocilizumab in the LITHE study
One of the major challenges of RA treatment is choosing the correct treatment and dose for the individual patient, as treatment response can be heterogeneous. To help select the appropriate treatment, there is a need for effective and non-invasive ways to monitor disease activity and progression. In the LITHE study, Bay-Jensen et al. investigate whether early biomarker measurements could predict early joint protection response to TCZ. The biomarkers (CRPM, VICM, C1M, C2M, C3M, and CTX-I/OC [bone turnover]) were measured at week 16 in 740 patients who were treated with placebo, 4 or 8 mg/kg TCZ.
The best predictor for early TCZ response was high baseline CTX-I/OC, which had a 95.9% purity of selection on CAST analysis. Other markers that were associated with positive TCZ response included C1M, C2M, C3M, and a combination of biomarkers.
The results from this study show that RA patients, subject to IL6-R antagonism, can potentially be stratified into responders and non-responders as early as 4 weeks post treatment. The CTX-I/OC biomarker could potentially be used to assist in identification of TCZ responsive RA patients.