AIM: A prednisone and calcineurin inhibitor (CNI)-free protocol was compared with a sirolimus, cyclosporine A (CsA), and prednisone-based immunosuppressive regimen for simultaneous pancreas-kidney transplantation (SPK). METHODS: A nonrandomized, single-center, sequential study enrolled low-immune responder SPK transplant recipients. The prednisone/CNI-free (minimization) group of 22 patients received thymoglobulin followed by sirolimus and reduced-dose CsA. Prednisone was withdrawn on day 5, and recipients were converted from CsA to mycophenolic acid at 6 months posttransplantation. The sirolimus/CsA group of 20 consecutive recipients transplanted immediately before this series received thymoglobulin followed by sirolimus, reduced-dose CsA, and prednisone. RESULTS: Donor and recipient demographic variables were equivalent between groups. The 24-month actual patient, kidney, and pancreas survivals for the minimization group were 100%, 100%, and 91% vs. 100%, 95%, and 95% for the sirolimus/CsA group (P=not significant [NS] for patient, kidney, and pancreas survivals). One acute rejection occurred in the minimization group and none in the sirolimus/CsA group. After withdrawal of CsA at 6 months, the minimization group showed an increase in mean estimated glomerular filtration rate, resulting in a significant improvement in renal function compared with the sirolimus/CsA group. At 24 months, the mean glomerular filtration rate of the minimization and sirolimus/CsA groups was 71.6+/-11.2 mL/min/1.73 m and 60.1+/-13.4 mL/min/1.73 m, respectively (P<0.05). Mean fasting blood glucose levels were equivalent between groups at all time points studied. CONCLUSION: Low-immune responder SPK recipients receiving a prednisone/CNI-free protocol achieved similar 2-year graft survivals and improved renal function compared with those treated with a sirolimus, CsA, and prednisone regimen.