Renal function and safety in stable kidney transplant recipients converted from immediate-release to prolonged-release tacrolimus

This multicenter, open, phase IIIb study assessed short-term efficacy, safety and dose adjustments in adult stable renal transplant recipients converted from tacrolimus twice-daily (BID) to once-daily (QD). Patients receiving unchanged tacrolimus BID for ≥ 12 weeks were enrolled, and after 6-weeks, converted from tacrolimus BID to QD (morning dose) on a 1 : 1 (mg : mg) total daily dose basis, for a further 12 weeks. Primary endpoint: change in steady-state creatinine clearance between treatment phases. Secondary endpoints: biopsy-proven acute rejection (BPAR), patient and graft survival, safety. 128 patients enrolled (mean age 48.9 years; time post-transplant 48.9 months); 91 evaluated for the primary endpoint. Mean total daily dose was 0.06 mg/kg (BID) and 0.07 mg/kg (QD); 79.1% required one/no dose changes post-conversion to maintain recommended blood-trough levels; average dose increase was small (0.6-0.7 mg/day) with more dose increases in patients on the lowest tacrolimus BID doses. Renal function remained stable and non-inferiority of tacrolimus QD against tacrolimus BID was demonstrated. There were no BPAR episodes; patient and graft survival were 100%. Adverse events were few; none led to dose modifications/discontinuation. Tacrolimus BID to tacrolimus QD conversion is straightforward and does not compromise renal function in stable kidney transplant patients in the short term.