Study to Evaluate Pharmacokinetic and Bioavailability of Envarsus® vs. Advagraf® in Liver Transplant Recipients

Inclusion Criteria: 1. Ability to understand the patient information and to personally sign and date the informed consent to participate in the clinical trial, before completing any clinical trial related procedures. 2. Male or female recipients ≥ 18 years of a liver graft from a deceased or living donor 3. The patient must receive a twice daily Tacrolimus based immunosuppression treatment. 4. Females of child-bearing potential who agree to comply with any applicable contraceptive requirements of the protocol or females who are permanently sterilized (at least 6 weeks post sterilization). 5. Non-pregnant, non-lactating female. 6. Recipients of a first or re-liver transplant in the last 30 days 7. The patient is co-operative and available for the entire clinical trial. Exclusion Criteria: 1. Patients with a known hypersensitivity to any of the drugs used in the study. 2. Patients who are not able to take oral medication at the time point of randomization. 3. Recipients of combined organ transplants. 4. Patients who are recipients of AB0 incompatible transplant grafts. 5. Currently participation in a clinical trial and any IMP intake within the last four weeks. 6. Patients who use drugs known to strongly interact with the cytochrome P-450 3A4 pathway and therefore influence the tacrolimus blood level are not allowed during Envarsus®/Advagraf® treatment period. 7. Patient with renal impairment with need of dialysis treatment at the time point of randomization. 8. Patient with a quick value \< 30 % 9. Patient with a thrombocytopenia \<20 Mrd./L 10. Patients with a leukopenia \< 1.0 Mrd. / L 11. Patients with inability of oral food intake.