Sustained suppression of peripheral blood immune functions by treatment with mycophenolate mofetil correlates with reduced severity of cardiac allograft rejection.

Background: We tested the hypothesis that sustained suppression of immune functions by mycophenolate mofetil (MMF) throughout the dosing interval reduces the severity of rejection.

Methods: Four groups of rat heart allograft recipients were treated orally daily through Day 5 with either: "low-dose" MMF, 10 mg/kg once daily (QD) or 5 mg/kg twice daily (BID); or "high-dose" MMF, 20 mg/kg QD or 10 mg/kg BID. The following were determined for all animals on Day 6: pharmacokinetics (PK, using high-performance liquid chromatography) of mycophenolic acid (MPA); pharmacodynamics (PD, by flow cytometry quantitation of whole blood mitogen-stimulated lymphocyte proliferation and expression of diverse T-cell surface activation molecules); and histologic graft rejection scores (RS).

Pharmacodynamics of mycophenolate mofetil after heart transplantation: new mechanisms of action and correlations with histologic severity of graft rejection.

The primary mechanism of action in vivo of mycophenolate mofetil (MMF) is believed to be inhibition of lymphocyte proliferation. We used novel assays of lymphocyte functions (pharmacodynamics, PD) in whole blood collected from rat heart allograft recipients treated with MMF to investigate the mechanisms of action of the active metabolite of MMF, mycophenolate acid (MPA) in vivo. Allograft recipients were treated orally once daily with 3 different doses of MMF.