Administration of mycophenolate mofetil in a murine model of acute graft-versus-host disease after bone marrow transplantation.
BACKGROUND: Graft-versus-host disease (GVHD) remains the most significant obstacle to the use of allogeneic bone marrow transplantation as a treatment for leukemia and other hematological malignancies. Because current GVHD treatment regimens such as cyclosporine and methotrexate are only partially effective, there is a need for new immunosuppressive drugs for the treatment of this condition. METHODS: A recently developed immunosuppressive drug, mycophenolate mofetil (MM), was tested in a fully mismatched (C57BL/6 donors to BALB/c recipients) murine model of acute GVHD after bone marrow transplantation. RESULTS: A dose regimen of 30 mg/kg/day given by oral gavage and begun at 1 day before transplant had no positive effect on survival and was found to retard the rate of marrow engraftment as measured by absolute blood neutrophil counts. In all subsequent experiments, treatment was begun on day 5 after transplant. Three different doses (30, 60, and 90 mg/kg/day) were tested, but no significant improvement in mean survival time (MST) was observed for the first two doses (P=0.412 and 0.100, respectively). The highest dose (90 mg/kg/day) reduced MST (P=0.059), and no further dose increases were attempted. MM in combination with cyclosporine also failed to improve MST compared with animals treated with cyclosporine alone or controls. CONCLUSIONS: These results suggest that MM given orally is not effective in this murine model of GVHD and may not have a role in the treatment and prevention of acute GVHD arising from bone marrow transplantation in the clinical setting.