Inolimomab [anti-CD25 monoclonal antibody B-B10, anti-interleukin-2 receptor monoclonal antibody B-B10, B-B10, BT 563, Leukotac®] is a murine IgG1-kappa monoclonal antibody directed against the &agr;-chain (pp55 region) of the human interleukin-2 receptor (CD25). It is undergoing clinical trials with Biotest Pharma in Germany for the suppression or reversal of graft-versus-host disorders (GVHD) and acute transplant rejection (phase III). It is also undergoing clinical trials in France (phase III) for GVHD, and clinical trials in the Netherlands (phase III) for the prophylaxis of organ transplant rejection.