Prophylactic daclizumab did not seem to prevent acute graft-versus-host disease (GVHD) in a multi-center, double-blind randomized trial involving 210 individuals who had unrelated marrow transplant for hematologic malignancies or severe aplastic anemia. Additionally, it tended to increase chronic GVHD risk and decrease relapse risk.

Participants were randomized to receive 5 weekly doses of daclizumab at 0.3 mg/kg (n=69), 1.2 mg/kg (n=76), or placebo (n=65) post-transplant. Investigators analyzed T cells in a subset of patients (n=107). Among the results:

• Patients treated with daclizumab saw their odds of relapse reduced by 43%.
• They also had increased risk of chronic GVHD, but the difference was not statistically significant.
• Survival odds were similar.
• In the subgroup analysis, daclizumab decreased the proportion of Tregs among CD4 T cells at days 11 through 35, and increased the proportion of central memory cells among CD4 T cells at 1 year.