The molecule CD32b is thought to be present on many B-cells including the malignant B-cells in some types of lymphoma and leukaemia. The study drug, BI-1206, is an anti-CD32b monoclonal antibody which attaches to CD32b on the surface of B-cells and is thought to act by recruiting host immune cells toward the tumour leading to cancer cell death as well as enhancing the anti-cancer effect of other anti-CD20 antibodies such as rituximab by stopping them being absorbed by cells.