Outcome of microemulsion cyclosporine C₂ concentration monitoring in kidney transplantation

Abstract: Profiling of absorption of cyclosporine (CsA) microemulsion is a concept in therapeutic drug monitoring (TDM) designed to optimize the clinical benefits of the drug in transplant recipients. A single blood concentration at 2 h (C₂) after CsA microemulsion administration in kidney transplant recipients accurately predicts graft outcome. An international guidelines has recommended the target C₂ over time-course post-transplantation. We determined whether this recommendation is appropriate for our patients who are Asian ethnic. The clinical data of these C₂ monitoring kidney transplant recipients were compared with the historical cohort of microemulsion CsA trough (C₀) level monitoring during the first 24-month post-transplantation. The inclusion and exclusion criteria were applied for both C₂ and C₀ cohorts. The mean target C₂ concentrations at 1, 3, 6, and 12-month post-transplantation were achieved in the C₂ cohort as the international guildlines. At 3-month post-transplantation, patients who had C₂ concentrations over 1500 ng/mL had higher serum creatinine as compared with those who had C₂ levels <1300 ng/mL (2.23 ± 0.8 vs. 1.44 ± 0.38 mg/dL: p = 0.01). Also, at 6-month post-transplantation, patients who had C₂ concentrations over 1300 ng/mL had higher serum creatinine (1.96 ± 0.29 vs. 1.37 ± 0.34 mg/dL: p < 0.01) as compared with those who had C₂ levels <1100 ng/mL. There was no statistical difference of acute rejection episodes between the two cohorts. The international consensus for C₂ concentraion may be too high for Asian ethnic kidney transplant recipients. The data from this study indicated lower than recommended C₂ concentraion as an appropriate C₂ target concentraion.