Physician-Directed Mycophenolate Mofetil Dose Reduction After Kidney Transplantation: A Multicenter Real Word Experience.

Background: Mycophenolate mofetil (MMF) dose is commonly reduced after kidney transplantation (KT). This study examined MMF dosing in the first 5 years after KT to determine if a lower MMF dose impacted outcomes.

Methods: We retrospectively studied 432 recipients who underwent KT between February 2012 and February 2015 in 3 centers. Induction was with IL-2 receptor blocker (23%) or depleting antibody (67%) and maintenance was with calcineurin inhibitor, MMF 1.5 to 2g/day and in 70% prednisone. MMF dose was reduced within the first post-KT year as clinically indicated or for elevated mycophenolic acid (MPA) levels. All 432 patients underwent 1-year protocol biopsy. Donor-specific antibodies (DSAs) were assessed at 1 year.

Results: At 1 year, 219 KT recipients (51%) received standard MMF (> 1 g/day) and 213 (49%) received low MMF (≤ 1 gr/d). Low MMF was for clinical indication (49%) or elevated MPA level (51%). At 1 year, there was no difference in rejection rate, type and degree of rejection, degree of inflammation, or DSA formation between the low and standard MMF groups (P = not significant [NS]). The reason for MMF dose reduction did not impact outcome. By 5 years, 69% of the KT recipients were on ≤ 1 g/d MMF. The 5-year patient and death-censored graft survival were comparable between the low and standard MMF groups.

Conclusions: Almost 50% of KT recipients were on low dose MMF at 1 year and this percentage increased by 5 years. We did not observe a difference in outcomes between those on standard or low MMF dose regardless of the reason for dose reduction. Physician-directed MMF dose-reduction may be safe but randomized studies are needed to validate this finding.