An Open-label Study to Assess the Safety, Efficacy, and Cellular Kinetics of YTB323 in Relapsing Multiple Sclerosis

This trial is testing YTB323, a type of CAR-T cell therapy (engineered immune cells designed to attack a specific target on immune cells), in people with relapsing multiple sclerosis (MS) — a condition where the immune system mistakenly attacks the nervous system. The therapy involves re-engineering a patient's own immune cells to reduce the harmful immune response. **You may be eligible if...** - You are between 18 and 60 years old - You have been diagnosed with relapsing multiple sclerosis - Your disease has broken through (worsened) while you were on a strong MS medication like rituximab, ocrelizumab, natalizumab, ofatumumab, ublituximab, or alemtuzumab - You have had a recent relapse or new MRI changes showing disease activity - Your organ function is adequate **You may NOT be eligible if...** - Your MS has not shown breakthrough activity while on a high-efficacy therapy - You have serious kidney, liver, heart, or blood count issues - You have certain infections or immune conditions that could make this therapy dangerous Talk to your doctor to see if this trial is right for you.