Background: Everolimus (EVL) and sirolimus (SRL) were introduced into immunosuppressive regimens, in an attempt to replace or reduce the dose of the nephrotoxic calcineurin inhibitors (CNI). In our institution, due to an administrative decision, conversion from SRL to EVL, was carried out, providing us the opportunity to investigate the effectiveness and safety profile of both drugs and to review the practical conversion dose between them.
Methods: We retrospectively analyzed the medical records of 51 maintenance kidney transplant recipients receiving an SRL-based CNI-free regimen, who were switched to EVL. SRL dose was concentration controlled to a through level of 4-8 ng/mL. Patients were converted to a variable dose of EVL that was adjusted to achieve a trough concentration of 3-8 ng/mL.
Results: SRL mean dose at time of conversion was 2.0 ± 0.9 mg/d. Initial EVL mean dose was 1.3 ± 0.5 mg/d. Six months after conversion, mean EVL trough level was 6.2 ± 2.8 ng/mL. EVL dose at this point was 2.0 ± 0.9 mg/d, which was not statistically different from SRL dose at the time of conversion (p = 0.575), suggesting a conversion factor of 1:1. During this six month period post conversion, no significant changes were observed in serum creatinine, hematocrit level, platelet count, proteinuria or lipid levels. No patient experienced an acute rejection episode.
Conclusions: Conversion from SRL to EVL in renal transplant recipients receiving a CNI-free immunosuppressive regimen can be performed safely with a low trough level range of EVL. We report for the first time a conversion factor between SRL and EVL.
© 2011 John Wiley & Sons A/S.