Treatment of B-cell lymphomas with combination of bispecific antibodies and saporin.

We report the use of a bispecific F(ab')2 antibody to target the ribosome-inactivating protein saporin to the surface antigen CD22 in the treatment of low-grade, end-stage, B-cell lymphoma. Four patients were treated. Toxic effects were minimal (grade I), with mild fever, weakness, and myalgia for 1-2 days after treatment. One patient showed an antibody response to mouse Fab' and saporin. All patients showed rapid and beneficial responses to treatment with improvements in most disease sites and in peripheral blood cytopenia. The responses were short-lived (less than 28 days) but further study of this targeting system is warranted.