Single Center, Pilot Evaluation of Home-based Therapeutic Drug Monitoring for Tacrolimus and Mycophenolate in Kidney Transplantation

Optimal immunosuppression therapy, most commonly with tacrolimus and mycophenolate, is critical for kidney transplantation success. While graft and patient survival are multifaceted phenomena, they are commonly attributed to chronic, subclinical immune-mediated damage, tacrolimus nephrotoxicity, or premature death secondary to complications amplified by immunosuppression such as infection, malignancy, and cardiovascular disease. New approaches are required to explore ways to optimize the precision dosing of immunosuppression to reduce the associated significant long-term side effects with the potential to improve kidney transplantation outcomes.

Currently, immunosuppressant dose adjustments empirically balance efficacy and toxicity in conjunction with limited tacrolimus blood concentrations. However, both tacrolimus and mycophenolate possess interpatient variability in drug exposure and response with considerable overlap between therapeutic and adverse effects. Only tacrolimus is routinely monitored as mycophenolate trough concentration is not correlated with drug exposure or outcomes. The pharmacokinetic parameter area under the concentration-time curve (AUC) offers a greater understanding of total drug exposure and has been associated with improved outcomes for both tacrolimus and mycophenolate. Yet, AUC is not routinely determined because it is impractical due to the need for multiple repeated samples in the clinic.

The investigators propose a prospective, single-center pilot study to evaluate the ability of a text messaging intervention coupled with a novel lancet device, the Tasso-M20, to facilitate the collection of dried blood samples by the patient at home for AUC estimation. The goal of the project is to develop a patient-centric strategy to allow frequent, longitudinal, minimally invasive sample collection which allows for more detailed assessments of immunosuppression exposure.

The primary objective is to compare the effect of bidirectional text communication on adherence to and accuracy of home-based AUC collection versus unidirectional text reminders in kidney transplant recipients receiving tacrolimus and mycophenolate.

The secondary objective is to assess the bioanalytical agreement of two sample collection methods (dried blood spot and venipuncture) as measured by Liquid Chromatography with tandem mass spectrometry (LC-MS/MS).