Conversion From Immediate-Release Tacrolimus to Prolonged-Release Tacrolimus in Stable Heart Transplant Patients: A Retrospective Study

Background. Lifelong adherence with post-transplant immunosuppression is challenging, with nonadherence associated with greater acute rejection (AR) risk. Methods. This retrospective study evaluated conversion from immediate-release tacrolimus (IRT) to prolonged-release tacrolimus (PRT), between January 2008 and December 2012 in stable adult heart transplant recipients. Cumulative incidence rate (IR) of AR and infection pre- and postconversion, safety, tacrolimus dose and trough levels, concomitant immunosuppression, and PRT discontinuation were analyzed (intention-to-treat population). Results. Overall, 467 patients (mean age, 59.3 [SD, 13.3] years) converted to PRT at 5.1 (SD, 4.9) years post transplant and were followed for 3.4 (SD, 1.5) years. During the 6 months post conversion, 5 patients (1.1%; 95% CI, 0.35%-2.48%) had an AR episode and IR was 2.2/100 patient-years (95% CI, 0.91-5.26). Incidence of rejection preconversion varied by time from transplant to conversion. Infection IR was similar post- and preconversion (9.2/100 patient-years [95% CI, 7.4-11.3] vs 10.6/100 patient-years [95% CI, 8.8-12.3], respectively; P = .20). Safety variables remained similar post conversion. The IR of mortality/graft loss was 2.3/100 patient-years (95% CI, 1.7-3.1). Conclusions. Conversion from IRT to PRT in heart transplant recipients in Spain was associated with no new safety concerns and appropriate immunosuppressive effectiveness.