*Purpose: Donor specific antibodies (DSA), whether pre-formed or developed de novo after kidney transplantation, have been associated with acute and chronic antibody mediated rejection, transplant glomerulopathy and graft loss. Development of DSA was not evaluated when comparing tacrolimus immediate release (tac-IR) to a novel formulation of tacrolimus, tacrolimus extended-release (LCP-Tac) or LCPT. At our center, a protocol change was made in 2015 to initiate de novo use of LCP-Tac in place of Tac-IR. The purpose of this study was to evaluate the development of DSA and DSA-related outcomes between these two formulations.

*Methods: We performed a retrospective cohort analysis of adult kidney transplant recipients at a single center from 1/2015 to 6/2017 who received either Tac-IR or LCP-Tac and remained on the same formulation for the first year post-transplant. The primary outcome was development of de novo DSA in the first year post-transplant. Secondary outcomes include incidence of antibody mediated rejection, graft loss, and GFR at 3, 6, and 12 months post-transplant. DSA characteristics were also evaluated.

*Results: : 445 patients met the inclusion criteria, 229 patients received LCP-Tac and 216 received Tac-IR. The LCP-Tac group were significantly older with higher Class I PRA and Class II PRA at the time of transplant. There were no differences in sex, race, history of diabetes or hypertension, type of induction, duration of dialysis, or type of donor between groups. The primary outcome of de novo DSA formation in the first year occurred in 6.1% (n=14) of patients in the LCP-Tac group compared to 3.2% (n=7) of patients in the Tac-IR group, p=0.153. There were no differences in antibody mediated rejection (3.9% vs. 2.3%, p=0.329) or graft loss (3.5% vs. 5.1%, p=0.404) in the LCP-Tac and Tac-IR groups, respectively. As shown in Table 1, there were no differences in GFR at 3, 6, and 12 months between the groups. The incidence of Class I, II and mixed I/II DSAs was 35.7%, 28.6%, and 35.7% in the LCP-Tac group, whereas the incidence of Class I, II, and mixed I/II DSAs was 28.6%, 57.1%, and 14.3% in the Tac-IR group. Class II DSAs were the immunodominant DSA identified in 64.2% and 71.4% of the LCP-Tac and Tac-IR groups, respectively. Table 1

*Conclusions: Use of de novo LCP-Tac was not associated with differences in development of de novo DSA or incidence of AMR compared to Tac-IR. We believe that this gives further support to de novo use of LCP-Tac after kidney transplantation.

« Back to 2019 American Transplant Congress