Introduction: Medication non-adherence continues to affect our adolescent kidney transplant recipients. Standard immunosuppressive regimen in pediatric kidney transplant patients at our center include Tacrolimus and Mycophenolate (MMF) with or without steroids. Despite the availability of once daily extended release (ER) Tacrolimus, once daily anti-metabolite option was traditionally not available, thus necessitating patients to take twice daily MMF.  The additional burden of timed twice daily medications creates a barrier to adherence, especially for the adolescent population. We trialed patients on a once daily regimen of Tacrolimus ER and Myfortic dosed at minimum 600mg/m2 once daily with or without prednisone. We hypothesized that once daily immunosuppression regimen administered all together at a convenient time in the day will potentially improve medication adherence and thereby prolong graft survival.
Methods: A retrospective chart review was conducted to identify patients placed on once daily regimen as described above. We evaluated the cohort for acute cellular rejection (ACR), antibody mediated rejection (AMR), donor specific antibodies (DSA), graft function, neutropenia, viremia, and graft loss for 1 year after initiation of Myfortic.
Results: A total of 48 patients (8-22 years of age) were included who were converted from twice daily medications to a once daily regimen (7 months to 16.5 years post-transplant); 23 were steroid-based and 25 steroid-free. Seven patients (14%) presented with biopsy proven ACR within 3 months of starting the new regimen, which resolved with treatment, and 1 patient had AMR within 2 weeks of starting the new regimen.  Three patients developed de-novo DSA within the year following initiation.  The mean MFI of DSAs was 2625 pre-initiation of Myfortic and 2667 post initiation, thus there was no significant change of DSA.  GFR remained unchanged.  There was no graft loss.  There were no infections nor evidence of neutropenia.  There were no significant episodes of viremia, defined as patients requiring intervention or treatment.  The regimen was well tolerated with no report of gastrointestinal or other side effects. 

Conclusion: Once daily Mycophenolate Acid is well tolerated and offers patients the ability for once-a-day immunosuppression regimen and improved medication adherence without increasing the risk of graft loss.  There was no observed increased risk of viremia or associated deterioration of GFR or DSA.  The safety and efficacy of this regimen should be studied in a large scale randomized controlled study.