RecruitingDevice studyUltrasound Neuroimmune Modulation in Adults With Rheumatoid ArthritisThis two-stage, multicenter clinical trial is designed to evaluate the feasibility, safety, and preliminary efficacy of splenic ultrasound stimulation to activate immune-neuromodulation (SUSTAIN) in patients with rheumatoid arthritis (RA) and at least moderate disease activity. The findings from this trial will directly inform the design and power calculations for a future pivotal trial by identifying an appropriate effect size and confirming protocol feasibility and safety.