Summary
This phase II trial tests how mosunetuzumab with or without polatuzumab vedotin works in treating patients undergoing chemotherapy followed by chimeric antigen receptor (CAR) T-cell therapy for diffuse large B-cell lymphoma that has come back (recurrent) or does not respond to treatment (refractory) or in patients with grade IIIB follicular lymphoma. Mosunetuzumab is a monoclonal antibody that binds to a protein called CD3, which is found on T cells (a type of white blood cell). It also binds to a protein called CD20, which is found on B cells (another type of white blood cell) and some lymphoma cells. This may help the immune system kill cancer cells. Polatuzumab vedotin is a monoclonal antibody called polatuzumab, linked to an anticancer drug called vedotin. Polatuzumab vedotin attaches to specific molecules (receptors) called CD79B, which is found on B cells and some lymphoma cells and delivers vedotin to kill them. It is a form of targeted therapy and a type of antibody-drug conjugate. Fludarabine is in a class of medications called purine analogs. It stops cells from making DNA and may kill cancer cells. It is a type of antimetabolite. Cyclophosphamide is in a class of medications called alkylating agents. It works by damaging the cell’s DNA and may kill cancer cells. It may also lower the body’s immune response. CAR T-cell therapy is a type of treatment in which a patient's T cells are changed in the laboratory so they will attack cancer cells. T cells are taken from a patient’s blood. Then the gene for a special receptor that binds to a certain protein on the patient’s cancer cells is added to the T cells in the laboratory. The special receptor is called a chimeric antigen receptor. Large numbers of the CAR T cells are grown in the laboratory and given to the patient by infusion for treatment of certain cancers. Giving mosunetuzumab with or without polatuzumab vedotin after chemotherapy and CAR T-cell therapy may be more effective at controlling or shrinking relapsed/refractory diffuse large B-cell lymphoma or grade IIIB follicular lymphoma than not giving them.