The protocol plan was a two stage, controlled, phase II study to assess safety and compare the grade of acute graft-versus-host disease (GVHD) with visilizumab, or Anti-thymocyte Globulin (ATG) in combination with tacrolimus + methotrexate in patients at high risk of GVHD after transplant from unrelated donors mismatched for 1-2 alleles of any type at human leukocyte antigen (HLA) A, B, C and DRB1.~The study design included two stages. The first stage of the trial was to enroll 15 patients on a single arm to be treated with study treatment (visilizumab, tacrolimus and methotrexate) to assess for treatment safety and exclude intolerable GVHD. The second stage of the trial was to include a random control group of patients treated with the current standard treatment (ATG, tacrolimus, and methotrexate) or study treatment. The purpose of this comparison was to determine if the study treatment visilizumab causes less severe side effects and if it is more potent in reducing graft-versus-host disease symptoms than the standard treatment.
The purpose of this study was to test whether a new drug named visilizumab would decrease the severity of graft-versus-host disease in patients treated with a mismatched donor. Investigators planned to use visilizumab in combination with tacrolimus and methotrexate as the study treatment.