Evaluation of tacrolimus abbreviated area-under-the-curve monitoring in renal transplant patients who are potientially at risk for adverse events

In a cohort of 32 renal transplant patients who are potentially at risk for adverse events, we compared tacrolimus (TAC) abbreviated AUC values calculated by a method developed in Asians (AUCw) with those derived for Caucasians (AUCa). The relationships between TAC trough (C0), abbreviated AUC, and biopsy results were also assessed. Forty-eight AUCs and 15 associated biopsies were evaluated. For AUCs obtained only from Caucasian patients, median AUCw value was lower than that of AUCa (104 vs. 115 ng x h/mL, n = 29, p < 0.0001). AUCs obtained from the two methods for all patients correlated with C0 (r(s) > 0.72, n = 48, p < 0.0001). Median AUCw (72.9 vs. 174 ng x h/mL, p = 0.043) and AUCa (81.0 vs. 203 ng x h/mL, p = 0.043) were lower in patients experiencing biopsy-proven acute rejection (AR) than those with normal histology. C0 tended to be lower in biopsies showing AR > 6 months post-transplant (5.80 vs. 11.0 ng/mL, p = 0.110). Thus, lower abbreviated AUCs were obtained for Caucasians using a method developed in Asians. C0 correlated well with abbreviated AUCs. Lower C0 and AUC appeared to be associated with biopsy-proven AR > 6 months post-transplant. Further prospective evaluation of TAC AUC and C0 monitoring in a larger cohort of patients is warranted.