Efficacy of Envarsus XR and Digital Health Technology in Reducing Tacrolimus Fluctuation and Frequency of Dose Changes

Tacrolimus is a calcineurin-inhibitor immunosuppressant indicated for the prophylaxis of organ rejection in patients receiving allogeneic liver, kidney or heart transplants, in combination with other immunosuppressants. Envarsus XR (extended release tacrolimus) is a long acting form of tacrolimus that is prescribed as a single dose per day (every 24 hours) rather than immediate release tacrolimus (IR-Tac) which is prescribed as a two doses per day (every 12 hours).

In post-kidney transplant patients, tacrolimus blood trough level must be monitored frequently, and dose adjustments must be made as necessary to keep trough level within a very narrow therapeutic range. High intra-patient variability (IPV) has also been reported to promote donor-specific antibody development, increased graft rejection rates and poor long-term outcome after kidney transplantation. In addition to increased potential for poor graft outcomes, these fluctuations and frequent dose adjustments are confusing and burdensome for patients, add to costs via medication expenses and need for lab checks, and consume the limited resources of transplant centers.

Similarly, non-adherence with immunosuppression medications is common and also linked to poor graft outcomes in kidney transplant patients.

High tacrolimus IPV can be a marker of medication non-adherence. The presence of medication non-adherence could be due to multiple factors such as forgetfulness to take the medication or remembering the correct dose, misunderstanding or miscommunication due to language barrier or logistical issues. High tacrolimus IPV could also be due to difficulty in taking medication every 12 hours, variation in bioavailability of different generic tacrolimus formulations or drug interactions. Considering the IPV of Tacrolimus level, patients and their families often have difficulty managing medications, especially during frequent changes in medication doses. This problem is more prevalent for older patients, who are often on multiple medications and for whom side effects and drug-drug interactions may lead to more harm. Once daily tacrolimus has had mixed results in reducing tacrolimus IPV. Very few studies have been done till now to measure the IPV among patients who received twice daily IR-Tac and converted to once daily Envarsus-XR. These studies were able to show significant reduction in IPV among patients who had high IPV prior to conversion. It is also noteworthy as compared to Astragraf, Envarsus XR has a more favorable pharmacokinetic profile. Envarsus XR uses Melt Dose technology to increase bioavailability and allow a more controlled release of the drug. This results in less fluctuation between maximum ("peak") exposure and trough. From a clinical perspective, Envarsus is noninferior in terms of efficacy (composite endpoint, including kidney transplant graft loss, death, biopsy-proven acute rejection and loss to follow-up) when compared to IR-Tac with a similar safety profile.

Digital health technologies have not been studied in regards to tacrolimus IPV but have shown promising results in improving medication adherence, including in kidney transplant population. TransMedAxTM application; a proposed digital health platform that will be developed to be used in this study. It will utilize dynamic QR code based technology customized to each individual patient, to improve medication adherence. It is especially geared towards patient populations who have frequent changes in medication dosages and have limited English language proficiency. A brief description of TransMedAxTM workflow is as follows: