New Approaches in TransplantationKidney transplantationMycophenolate Mofetil Withdrawal With Conversion to Everolimus to Treat BK Virus Infection in Kidney Transplant Recipients

•In vitro data suggest an inhibitory effect of mTOR inhibitors on BK virus replication.•Conversion to everolimus from MMF versus MMF reduction did not result in improved BK virus clearance at 3 months.•At 1 year there was a nonstatistically significant trend toward improved clearance with everolimus conversion.

BackgroundBK virus (BKV) is a significant post-transplant infection. Mammalian target of rapamycin inhibitors (mTORis) reduce BKV large T antigen expression in vitro and are associated with lower rates of BKV infection when used as de novo immunosuppression in clinical studies.MethodsWe performed a prospective, single-center, randomized, open label pilot trial to evaluate the impact of mycophenolate mofetil (MMF) withdrawal with conversion to the mTORi everolimus versus a 50% reduction of the MMF dose for the treatment of BKV infection after kidney transplantation. Patients maintained on tacrolimus, MMF, and corticosteroids that developed BK viremia or BK viruria ≥1 × 106 copies/mL were eligible. The primary endpoint was a >50% reduction of BK viruria or clearance of viremia at 3 months postrandomization.ResultsForty patients were enrolled and randomized in a 1:1 manner; 11 (55%) and 8 patients (40%) reached the primary endpoint in the everolimus group and the MMF group, respectively (P = .53). Of those with BK viremia at the time of enrollment, 8 of 16 (50%) and 5 of 15 (33.3%) cleared the viremia by month 3 in the everolimus conversion and MMF dose reduction groups, respectively (P = .47).ConclusionConversion from MMF to everolimus in BKV infection demonstrated a trend toward improved viral clearance but did not reach statistical significance.