Tacrolimus exposure in the real world: An analysis from the Mycophenolic acid Observational REnal transplant study

Tacrolimus exposure and renal function data to 36 months post-transplant were analyzed from the prospective, observational Mycophenolic acid Observational REnal transplant (MORE) registry in which de novo kidney transplant patients were managed according to local practice. Tacrolimus trough (C₀) concentration at month 12 was stratified as low (<6 ng/mL), moderate (6-8 ng/mL), or high (>8 ng/mL) in 724 patients. Estimated glomerular filtration rate (eGFR) was stratified as low (<60 mL/min/1.73 m²) or high (≥60 mL/min/1.73 m²). High tacrolimus C₀ (>8 ng/mL) was observed in 47.7%, 34.1%, 26.8%, and 26.7% of patients at baseline and months 12, 24, and 36, respectively. Biopsy-proven acute rejection was similar to month 36 regardless of tacrolimus C₀ category at month 12. Tacrolimus C₀ >8 ng/mL vs. <6 ng/mL at month 12 was predictive of low eGFR at month 24 (p = 0.023) with a nonsignificant trend at month 36 (p = 0.085). Infections (p < 0.013) and BK virus infection (p < 0.001) were most frequent in the low tacrolimus C₀ cohort. Neutropenia was most frequent in the high tacrolimus C₀ category (p = 0.010). In conclusion, over a quarter of patients were exposed to high tacrolimus C₀ to 36 months post-transplant. Tacrolimus exposure did not affect rejection risk, but tacrolimus C₀ >8 ng/mL at month 12 was predictive of subsequent low eGFR compared to C₀ <6 ng/mL.