Targeting Lymphoma with Bispecific Antibody-Armed T Cells and their Potential for use in an Allogeneic Setting (41.31)

Abstract

Abstract Patients with high-risk refractory or relapsed lymphomas face a poor prognosis and limited therapeutic options. Current treatment regimens of chemotherapy with either rituximab (anti-CD20 mAb) or with allogeneic stem cell transplant (alloSCT) yield serious toxicities and high relapse rates. In particular, benefits of alloSCT are grossly limited by life-threatening graft vs host disease (GvHD). New approaches to enhance graft vs lymphoma (GvL) effects without increased GvHD are needed. Bispecific antibodies (BiAbs) are produced by linking anti-CD3 for T cell binding to an antibody specific for a tumor antigen. Anti-CD3 activated T cells (ATC) "armed" with BiAb express tumor-specific CTL function independent of further activation, proliferation, antigen presentation or costimulation. Studies here examined allo-reactivity of BiAb-armed ATC for potential application in an allogeneic setting. Data show that ATC armed with anti-CD3 x anti-CD20 BiAb specifically target and kill B cell lymphomas. However, BiAb-armed ATC are remarkably poor stimulators of, or responders to, allo-stimlulation. These results provide important evidence of a functional separation between the GvL and GvH effects of BiAb-armed ATC.