Background For years, we have been looking for effective immunosuppressive regimens, but tolerability of the drug is important too. Otherwise patients cannot tolerate the drug and the incidence of death, graft loss or premature treatment withdrawal will increase. New therapeutic approaches have been developed such as calcineurin inhibitors for mTOR inhibition. Our study aimed to increase the understanding of immunosuppression and adverse effects.

Purpose The purpose of this retrospective analysis was to investigate the short- and long-term safety profile of immunosuppressive regimes evaluated in the original study. In this current analysis, data from only a single centre were used, consisting of data from 185 kidney transplant recipients previously enrolled in the core study, between February/2008 to May/2010. These patients were followed for two years post-transplant.

Materials and methods This study is a retrospective safety analysis data from a larger open-label, randomised, multicentre study titled “Planned randomised conversion from tacrolimus to sirolimus-based immunosuppressive regimen in de novo kidney transplant recipients”, previously approved by our local ethics committee. Of 169 patients evaluated at month 3, 160 met the criteria for intervention. Of these 60 patients converted to sirolimus and 60 kept on initial tacrolimus-based maintenance therapy, as earlier randomised. The 41 patients who did not meet the month 3 criteria for the core protocol interventional plan were considered a non-criteria group and were also followed for 12 months.

Results Biochemical and haematological parameters were recorded at fixed time visits (month 3, month 12 and month 24) from groups (SRL versus TAC), including haemoglobin g/dL (M3:12.8 ± 1.61 × 13.1 ± 2.02; M12:13.6 ± 2.47; X14.1 ± 1.64; M24:13.41.83 ± X14 ± 1.69), leukocytesN/mm³ (M3:6938 ± 3218 × 64912789 ±; M12:6811 ± 2434X6011 ± 1985; M24:7622 ± 2902X7598 ± 2378), urine protein to creatinine ratio (M3: 0.3 ± 0.8X 0.1 ± 0.21; M120.3 ± 0.6X0.2X0.6; M24:0.5 ± 0.3 ± 8), creatinine mg/dL (M3: 1.30 ± 0.33X1.25 ± 0.30; M12:1.29 ± 0.33X1.27 ± 0.35; M24:1.33 ± 0.41X1.25 ± 0.35), clearance mL/min/m² (M3; M12; M24) cholesterol mg/dL (M3:17542 ± X179 ± 35; M12:225 ± 47X190 ± 43; M24:221 ± 53X187 ± 54) and cholesterol fractions, including LDL mg/dL, (M3:97 ± 35 × 102 ± 30; M12:134 ± 38 × 112 ± 34; M24:131 ± 39 × 108 ± 34) were collected.

Conclusions At the moment, the current study showed that biochemical and haematological values did not differ statistically, however, cholesterol fractions showed differences between immunosuppression regimes. In addition, all adverse events (serious or not) reported at medical records were evaluated, according to the Common Terminology Criteria for Adverse Event v.4. The incidence of infections and gastrointestinal disorders pre- and post-conversion was collected. This information will be explored at greater depth.

No conflict of interest.