This study is testing a new treatment, **NXC-201 CAR-T**, for patients with **light chain (AL) amyloidosis**, a condition where abnormal proteins build up in organs. This is an **open-label Phase 1b study**, meaning doctors and patients know what treatment is given, and it's early in testing. Patients who have tried other treatments without success can join. The process involves a blood procedure called **leukapheresis** at least a month before receiving NXC-201. After preparing the body with drugs called **cyclophosphamide** and **fludarabine**, patients receive NXC-201 on **Day 0**. Safety and effectiveness are monitored by a committee. **Key Points:** - Participation involves multiple medical visits and procedures over several months. - There are specific health criteria for joining, including age and previous treatments. - Some risks are involved, and participants must agree to certain safety rules, like using birth control. If you're interested, discuss with your doctor to see if this study is right for you. Ensure you understand the potential benefits and risks before joining.