Long-term follow-up of stable kidney transplant recipients after conversion from tacrolimus twice daily immediate release to tacrolimus once-daily prolonged release: a large single-center experience.

BACKGROUND

Adult kidney transplant recipients maintained on tacrolimus twice-daily (Tac BD) were given the opportunity to convert to tacrolimus once daily (Tac QD). Conversion was based upon a 1:1 mg:mg total daily dose ratio.

METHODS

Between November 2007 and September 2010, 589 patients were converted at a mean post-transplant period of 4.6 years. We retrospectively reviewed routine clinical records to assess the safety of conversion to Tac QD for up to 12 months post-conversion.

RESULTS

Tac QD mean dose barely changed from preconversion values. Mean exposure (tacrolimus trough blood level [Cmin]) remained within the target window but was reduced by 12% (P = NS) with a trend toward less interpatient variability. Renal function at 12 months remained stable within 2.5% of the preconversion mean value. There were 14 (2.4%) cases of biopsy-proven acute rejection: 6 (1.0%) borderline and 8 (1.4%) Banff grade ≥ IA. Actuarial first year post-conversion graft survival was 96.3% and patient survival 99.0%. Twenty-eight patients (4.8%) discontinued Tac QD and were switched to sirolimus: 19 for malignancy, 6 for thrombotic microangiopathy, and 3 with severe vascular changes; 3 patients were reconverted to Tac BD.

CONCLUSIONS

Conversion from Tac BD to Tac QD in renal recipients was accompanied by stable renal function, a low risk of acute rejection, and less interpatient variability in drug exposure.