De novo sirolimus with low-dose tacrolimus versus full-dose tacrolimus with mycophenolate mofetil after heart transplantation--8-year results

Abstract

Background: Although acute cellular rejection after heart transplantation (HTX) can be controlled by full-dose calcineurin inhibitor (CNI)-based immunosuppressive regimens, cardiac allograft vasculopathy (CAV), nephrotoxicity, and malignancy remain ongoing problems. To evaluate the potential beneficial effects of sirolimus and CNI reduction, we compared de novo low-dose tacrolimus and sirolimus with standard tacrolimus and mycophenolate mofetil (MMF)-based immunosuppression after HTX.

Methods: We analyzed a long-term follow-up cohort of 126 patients who underwent HTX during the period 1998-2005 and received either de novo low-dose tacrolimus/sirolimus (lowTAC/SIR; n = 61) or full-dose tacrolimus/MMF (TAC/MMF; n = 64).

Results: Freedom from treatment switch was less in the low TAC/SIR group than in the TAC/MMF group (51.7% vs 73.0%, p = 0.038) 8 years after HTX. Freedom from acute rejection was 90.6% in the low TAC/SIR group vs 80.3% in the TAC/MMF group (p = 0.100). There was no difference in freedom from International Society for Heart and Lung Transplantation CAV grade ≥ 1 (55.4% vs 60.0%, p = 0.922), time until CAV diagnosis (4.2 ± 2.0 years vs 3.2 ± 2.4 years, p = 0.087), and CAV severity (p = 0.618). The benefit of reduced early maximum creatinine for low TAC/SIR treatment (1.8 ± 0.9 mg/dl vs 2.4 ± 1.1 mg/dl in TAC/MMF group, p < 0.001) did not continue 5 years and 8 years after HTX (1.4 ± 0.4 mg/dl vs 1.7 ± 1.2 mg/dl, p = 0.333, and 1.6 ± 1.1 mg/dl vs 1.6 ± 0.8 mg/dl, p = 0.957). The trend for superior survival at 5 years with low TAC/SIR treatment (93.1% vs 81.3% in TAC/MMF group, p = 0.051) could not be confirmed after 8 years (84.7% vs 75.0%, p = 0.138). Multivariate analysis at 8 years did not reveal any benefit of low TAC/SIR treatment.

Conclusions: Reduction of de novo CNI did not result in superior long-term renal function. Low-dose mechanistic target of rapamycin inhibition did not achieve any benefit in CAV prevention compared with full-dose TAC/MMF after HTX.

Keywords: HTX; cardiac allograft vasculopathy; de novo sirolimus; long-term study; low-dose tacrolimus; malignancy; nephrotoxicity.