A phase I/II study of mycophenolate mofetil in combination with cyclosporine for prophylaxis of acute graft-versus-host disease after myeloablative conditioning and allogeneic hematopoietic cell transplantation.

Abstract In a phase I/II study, the combination of cyclosporine (CSP) and mycophenolate mofetil (MMF) was investigated as graft-versus-host disease (GVHD) prophylaxis after myeloablative conditioning and hematopoietic cell transplantation from an HLA-matched sibling donor. In phase I, 3 groups, each with 10 or 11 patients, received MMF (15 mg/kg) from day 0 to day 27 at decreasing dose intervals of every 12, 8, and 6 hours to determine a safe and effective total daily dose. At the 45 mg/kg/d dosage level, 4 of 11 patients developed only grade II GVHD, and a concentration at steady state of mycophenolic acid (the active moiety of MMF) consistent with a therapeutic range described for solid-organ transplantation was achieved. There was a suggestion of increased toxicity without improved efficacy at the 60 mg/kg/d dosage level. Accordingly, the 45 mg/kg/d dosage was therefore selected for phase II, and another 15 patients were added to this group from the phase I study (n=26). The concentrations at steady state for this dosage at days 0, 6, 13, 20, and 27 were 2.73, 3.02, 3.20, 2.62, and 2.64 microg/mL, respectively. No toxicities were attributed to MMF at this dose. The median time to engraftment after hematopoietic cell transplantation was 15 days (range, 10-20 days). The incidence of acute GVHD was 62%, which was comparable to a group of historical controls receiving CSP and methotrexate (MTX) for GVHD prophylaxis. Although a significant improvement in the prevention of GVHD was not suggested, compared with CSP and MTX, MMF in combination with CSP could be considered in cases in which MTX is contraindicated.