Once-daily, Prolonged-release Tacrolimus Vs Twice-daily, Immediate-release Tacrolimus in De Novo Living-donor Liver Transplantation: A Phase 4, Randomized, Open-label, Comparative, Single-center Study

Randomized, open-label, comparative, single-center, Phase 4, 24-week study comparing pharmacokinetics (PK), safety, and efficacy of once-daily, prolonged-release tacrolimus (PR-T) with twice-daily, immediate-release tacrolimus (IR-T) in adult de novo living-donor liver transplant (LDLT) recipients in Korea. All patients received intravenous tacrolimus from Day 0 (transplantation) for 4 days and were randomized (1:1) to receive oral PR-T or IR-T from Day 5. PK profiles were taken on Days 6 and 21. Primary endpoint: area under the concentration-time curve over 24 hour (AUC ). Predefined similarity interval for confidence intervals of ratios: 80%-125%. Secondary endpoints included: tacrolimus concentration at 24 hour (C ), patient/graft survival, biopsy-confirmed acute rejection (BCAR), treatment-emergent adverse events (TEAEs). One-hundred patients were included (PR-T, n = 50; IR-T, n = 50). Compared with IR-T, 40% and 66% higher mean PR-T daily doses resulted in similar AUC between formulations on Day 6 (PR-T:IR-T ratio of means 96.8%), and numerically higher AUC with PR-T on Day 21 (128.8%), respectively. Linear relationship was similar between AUC and C , and formulations. No graft loss/deaths, incidence of BCAR and TEAEs similar between formulations. Higher PR-T vs IR-T doses were required to achieve comparable systemic exposure in Korean de novo LDLT recipients. PR-T was efficacious; no new safety signals were detected.