An integrated sampling strategy for therapeutic mycophenolic acid monitoring in lung transplant recipients

BACKGROUND: Mycophenolic Acid (MPA) is the most used anti-proliferative in lung transplantation, but its pharmacokinetic (PK) variability has precluded therapeutic drug monitoring. Both genetic and clinical factors have been implicated in MPA variability. This study aimed to integrate genetic and clinical factors with PK measurements to quantify MPA exposure. METHODS: We performed 12-hour pharmacokinetic analysis on 60 adult lung transplant recipients maintained on MPA for immunosuppression. We genotyped a SLCO1B3 polymorphisms previously associated MPA metabolism and collected relevant clinical data. We calculated area under the curve (AUC0-12) and performed univariate linear regression analysis to evaluate its association with genetic, clinical, and pharmacokinetic variables. We performed lasso regression analysis to create final AUC estimation tools. RESULTS: PK-only measurements obtained 2, 3, and 8 hours after MPA administration (C2, C 3, and C8) were strongly associated with MPA AUC 0-12 (R2 67%, 67% and 68% respectively). Clinical and genetic factors associated with MPA AUC 0-12 included the MPA dose (p = 0.001), transplant diagnosis (p = 0.015), SLCO1B3 genotype (p = 0.049), and body surface area (p = 0.050). The best integrated single-sampling strategy included C2 and achieved an R2 value of 80%. The best integrated limited- sampling strategy included C0, C 0.25 , and C2 and achieved an R2 value of 90%. CONCLUSIONS: An integrated limited sampling strategy (LSS) for MPA allows increased accuracy in prediction of MPA AUC 0-12 compared to PK-only modeling. Validation of this model will allow for clinically feasible MPA therapeutic drug monitoring and help advance precision management of MPA. J Heart Lung Transplant 2025;44:46-56 (c) 2024 The Authors. Published by Elsevier Inc. on behalf of International Society for Heart and Lung Transplantation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).