Beneficial Effects of High-Dose Mizoribine on ABO-Incompatible Living-Related Kidney Transplantation: Two-Year Results by a Japanese Multicenter Study

Abstract

BackgroundMizoribine (MZ) has been developed as an immunosuppressive agent in Japan, but it has a less-potent immunosuppressive effect up to 3 mg/kg/d. In the previous study, a Japanese multicenter study, we reported that high-dose MZ, at 6 mg/kg/d, with a calcineurin inhibitor was effective and safe in reducing the frequency of cytomegalovirus (CMV)-related events in ABO-incompatible (ABO-i) living-related kidney transplantation (LKT). In the present study, therefore, we investigated the effects of high-dose MZ with a CNI in ABO-i LKT recipients in a Japanese multicenter study. MethodsA total of 37 patients were treated with high-dose MZ (6 mg/kg), a CNI (cyclosporine [CsA] or tacrolimus [Tac]), basiliximab (Bas), rituximab (Rit), and corticosteroids. CsA was started at a dose of 7 mg/kg to maintain blood levels [200 ng/mL (C0), 6000 ng-h/mL (AUC 0–9)]. Tac was started at a dose of 0.2 mg/kg to maintain blood levels [8–10 ng/mL (C0), 100 ng-h/mL (AUC 0–9)]. Bas (20 mg/body) was administrated on day 0 and day 4 after transplantation. Rit (100–200 mg/body) was administrated on day −14 and day −7 before transplantation. MZ was adjusted to maintain target C0 levels of 1.5 to 2.0 μg/mL. ResultsPatient and graft survival rates for 2 years were 100% in the CsA group (n = 22) and 93.3% in the Tac group (n = 15) (not significant, NS). Overall incidence of acute rejection for 2 years was 22.7% in the CsA group and 26.7% in the Tac group. Mean serum creatinine levels at 2 years were 1.29 ± 0.2 mg/dL in the CsA group and 1.21 ± 0.34 mg/dL in the Tac group (NS). The incidence of CMV disease was 0% in both groups, and positive rates of CMV antigenemia were 50.0% and 26.7% in the CsA and Tac groups, respectively (NS). Mean serum uric acid levels were 5.5 ± 1.3 mg/dL and 6.4 ± 1.2 mg/dL at 2 years (NS) in the CsA and Tac groups, respectively. ConclusionsA high-dose MZ regimen including calcineurin inhibitor (CsA or Tac), Bas, Rit, and steroids was effective and safe in reducing the frequency of CMV-related events in ABO-i LKT.