Mycophenolic Acid Plasma Trough Level: Correlation with Clinical Outcome

Abstract

Objectives: Assess the relationship between clinical diagnosis, state of immunosuppression, mycophenolic acid (MPA) plasma trough levels (MPACmin), and mycophenolate mofetil (MMF) dosage in renal transplant recipients.

Materials and Methods: MPACmin were determined in 30 kidney transplant patients, of whom 7 exhibited biopsy-proven acute rejection. The remaining 23 had normal graft function. Graft outcome, defined by clinical diagnosis and serum creatinine level, was compared according to MPACmin, MMF dosage, and total lymphocyte count (LC).

Results: Patients with acute rejection had similar MPACmin (2.4 ± 1.7 µg/mL), MMF dosages (1.7 ± 0.5 g), and LCs (0.001165 ± 0.0040 x 109/L) when compared with normal patients (2.2 ± 0.7 µg/mL, 1.7 ± 0.4 g and 0.001160 ± 0.00527 x 109/L) respectively. Rejection rates were comparable irrespective of MPACmin ranges and higher in those receiving the 1-g dose (30%) when compared with those receiving 1.5-g and 2-g doses (12.5% and 11.7%). No relationship was observed between MPACmin and MMF doses, and neither parameter correlated with LC.

Conclusions: These results suggest that MPACmin is a poor correlate of clinical outcome and state of immunosuppression. Although the usually recommended dosage of MMF (2 g) may be associated with acute rejection, low-dose MMF (1 g) seems to constitute a higher risk.