Bispecific antibodies against cd3 and cd20 for treating richter's syndrome

A method of treating Richter's syndrome (RS) in a human subject, the method comprising administering to the subject a bispecific antibody comprising:

• (i) a first binding arm comprising a first antigen-binding region which binds to human CD3ε (epsilon) and comprises a variable heavy chain (VH) region and a variable light chain (VL) region, wherein the VH region comprises the CDR1, CDR2 and CDR3 sequences that are in the VH region sequence of SEQ ID NO:
• 6, and the VL region comprises the CDR1, CDR2 and CDR3 sequences that are in the VL region sequence of SEQ ID NO:
• 7;
• and
• (ii) a second binding arm comprising a second antigen-binding region which binds to human CD20 and comprises a VH region and a VL region, wherein the VH region comprises the CDR1, CDR2 and CDR3 sequences that are in the VH region sequence of SEQ ID NO:
• 13, and the VL region comprises the CDR1, CDR2 and CDR3 sequences that are in the VL region sequence of SEQ ID NO:
• 14;
• wherein the bispecific antibody is administered at a dose ranging from 12-60 mg in 28-day cycles,
• wherein administration of the bispecific antibody continues at least until the subject exhibits a complete response (CR), a partial response (PR), or stable disease, or until progressive disease develops or unacceptable toxicity occurs.