ACE1831 in Adult Subjects With Relapsed/ Refractory CD20-expressing B-cell Malignancies

This study tests a new treatment called ACE1831 — a type of engineered immune cell therapy — for adults with a type of blood cancer called B-cell lymphoma (non-Hodgkin's lymphoma) that has come back or stopped responding to previous treatments. **You may be eligible if...** - You have a CD20-positive B-cell lymphoma that has returned or did not respond to at least 2 prior standard treatments - You have at least one measurable tumor - You are generally well enough to carry out normal daily activities (ECOG 0–1, or ECOG 2 with normal protein levels) - Your blood, kidney, liver, and heart function are adequate - Your blood oxygen level is at least 92% at rest **You may NOT be eligible if...** - You have previously received a CD20-targeted gene-modified cell therapy - You had an autologous stem cell transplant within the last 6 weeks, or any allogeneic (donor) stem cell transplant - You have a history of lymphoma in the brain or spine - You have an active serious infection or significant heart disease - You have uncontrolled HIV, active hepatitis B, or hepatitis C - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.