2.1 Study design and population
This is a retrospective, single center study. Patients who received lung transplantation at China-Japan Friendship Hospital from August 2016 to August 2022 were selectively enrolled according to the criteria for the study. The inclusion criteria were: (1) lung transplantation for the first time; (2) received TAC-based immunosuppressive therapy. The exclusion criteria were: (1) unable to participate in CYP3A5genotyping; (2) switched to cyclosporine or sirolimus; (3) incomplete baseline data; (4) survived less than three months.
All procedures in this study were in accordance with the 1964 Helsinki declaration and its amendments, and was approved by the Ethics Committee of China-Japan Friendship Hospital in June, 2022 (No. 2022-KY-056-1).
2.2 Immunosuppressive regimens
For induction therapy, patients received methylprednisolone alone or in combination with basiliximab. Methylprednisolone was given intraoperatively at a dose of 500–1000 mg. Basiliximab were given both before transplantation and on post-operative day (POD) 4 at a dose of 20 mg.
The maintenance immunosuppressive regimen consists of immediate-release capsules of TAC, immediate-release tablets of mycophenolate mofetil, and prednisone. TAC administration was initiated on POD 1 at a standard dosage of 2 mg per day, divided into two doses, unless the patient had an exceptionally high or low body weight. Monitoring of C0 commenced on POD 3 and continued thrice weekly during hospitalization, with additional blood draws conducted monthly or during follow-up visits. Per protocol in our center, the target ranges for TAC C0 were set at 8–10 ng/mL within the first year (0–12 months) and 6–8 ng/mL within the second year (12–24 months) after lung transplantation, respectively. Initially, mycophenolate mofetil was administered in a dose of 1000 mg/day divided into two doses. Prednisone was intravenously administered at a dosage of 1 mg/kg/day from POD 1 to POD 3, followed by oral administration at a dosage of 0.5 mg/kg/day which gradually tapered down to a long-term maintenance dose ranging between 5–10 mg/day.