In the last few years, much progress in avoiding acute and chronic rejection in transplanted patients has been made by introducing new and more effective drugs with different formulations and combinations, and fewer side effects. Standardized protocols have been proposed for different organs, but individualized therapy based on immunosuppressive therapy blood monitoring is necessary because of pharmacological interaction, new generic drug introductions, and different absorptions and biodistributions. In specific mycophenolate mofetil dosing through mycophenolic acid (MPA), therapeutic drug monitoring has demonstrated minimal risk of organ transplant rejection. Even if the MPA area under the 12 h concentration–time curve is more accurate than MPA levels, it appears to be resource consuming and clinically impractical because of the need for numerous blood samples. Limited sampling strategy (LLS) has been proposed to overcome this problem. In heart-transplanted patients, MPA LSS is useful in guiding clinical management and dosing. The purpose of this chapter is to describe the state of the art of MPA LSS employment in heart transplantation and to perform an update of the scientific literature.
Part of the book: Topics in Heart Failure Management
Mycophenolate mofetil (MMF) represents a cornerstone in heart transplant (HTx) treatment. The area under the 12-hour concentration-time curve (AUC0-12h) of mycophenolic acid (MPA) -MMF’s active drug- is associated with treatment outcome. Nonetheless, therapeutic drug monitoring (TDM) of MPA AUC0-12h is impractical to assess in clinical practice and Limited Sampling Strategies (LSSs) represent a consolidated tool to estimate AUC0-12h. Two LSSs were previously generated in a selected cohort of HTx recipients treated with MMF and cyclosporine (CsA). This pilot study aimed to test these LSSs in a cohort of non-selected HTx recipients treated with MMF combined with CsA or tacrolimus (TAC). Complete PK profile was performed in 40 adults HTx recipients. MPA-AUC0-12h was estimated by two algorithms, LSS3 and LSS4, based on 3 and 4 time-points. The evaluation was made through linear regression and Bland-Altman analyses. Both LSS3 and LSS4 tended to underestimate the value of MPA-AUC0-12h (mean percentage prediction error, MPE%: −6.0%; and −4.8%, respectively). Nonetheless, high correlations (r: 0.92 and 0.94, respectively) and goodness of fit of linear regression models (R2: 0.84 and 0.88, respectively) emerged for both LSSs. A study with a wider and more homogenous sample size should be performed to support these results.
Part of the book: Heart Transplantation