Fluorescence optical imaging is helpful in the decision for rituximab (RTX) re-therapy in patients with rheumatoid arthritis

Objective: To evaluate the ability of fluorescence optical imaging (FOI) Xiralite® in the prediction of RTX re-therapy in rheumatoid arthritis (RA) patients - in comparison to clinical, laboratory and musculoskeletal ultrasound (US) parameters. Patients and methods Patients with established RA were prospectively followed over one year by DAS28, patient’s global disease activity (VAS 0-100 mm), CRP and ESR, US7 score and FOI in phases 1-3 and automatically generated PrimaVistaMode (PVM) at baseline (before RTX) and after 3, 6, and 12 months. The need for RTX re-therapy was decided by the treating rheumatologist – blinded to imaging data. Results: : 31 patients (female 77.4%, mean age 60.1±11.4, mean disease duration 14.9±7.1 years) were included. Fourteen patients (45.2%) received RTX re-therapy within 12 months. In the group with RTX re-therapy, FOI in PVM mode was the only parameter that presented significant increase over time (beta 0.40, CI 0.08-0.71; p=0.013) – compared to the group without re-therapy. In the prediction model via ROC analysis, FOI in PVM reached the highest values of all imaging, clinical and laboratory parameters for the prediction of re-therapy over one year with an area under the curve (AUC) of 0.78 (OR 0.84, CI 0.72;0.98, p=0.031). US7 GS synovitis score revealed similar predictive power with an AUC of 0.73 (p=0.049). Conclusion: US7 GS synovitis score and FOI in PVM are able to discriminate between patients with and without need for RTX re-therapy better than clinical and laboratory parameters.