Impact of converting adult kidney transplant recipients with high tacrolimus variability from twice daily immediate release tacrolimus to once daily LCP-Tacrolimus

Background: The influence of converting to once daily, extended-release LCP-Tacrolimus (Tac) for those with high tacrolimus variability in kidney transplant recipients (KTRs) is not well-studied. Methods: Single-center, retrospective cohort study of adult KTRs converted from Tac immediate release to LCP-Tac 1-2 years post-transplant. Primary measures were Tac variability, using the coefficient of variation (CV) and time in therapeutic range (TTR), as well as clinical outcomes (rejection, infections, graft loss, death). Results: A total of 193 KTRs included with a follow-up of 3.2 ±.7 years and 1.3 ±.3 years since LCP-Tac conversion. Mean age was 52 ± 13 years; 70% were African American, 39% were female, 16% living donor and 12% donor after cardiac death (DCD). In the overall cohort, tac CV was 29.5% before conversion, which increased to 33.4% after LCP-Tac (p =.008). In those with Tac CV >30% (n = 86), conversion to LCP-Tac reduced variability (40.6% vs. 35.5%; p =.019) and for those with Tac CV >30% and nonadherence or med errors (n = 16), LCP-Tac conversion substantially reduced Tac CV (43.4% vs. 29.9%; p =.026). TTR significantly improved for those with Tac CV >30% with (52.4% vs. 82.8%; p =.027) or without nonadherence or med errors (64.8% vs. 73.2%; p =.005). CMV, BK, and overall infections were significantly higher prior to LCP-Tac conversion. In the overall cohort, 3% had rejection before conversion and 2% after (p = NS). At end of follow-up, graft and patient survival were 94% and 96%, respectively. Conclusions: In those with high Tac CV, conversion to LCP-Tac is associated with a significant reduction in variability and improvement in TTR, particularly in those with nonadherence or medication errors.