Adequacy of Initial Everolimus Dose, with and Without Calcineurin Inhibitors, in Kidney Transplant Recipients

Background: This study investigates the adequacy of initial everolimus (EVR) dose, with and without calcineurin inhibitors (CNI), in kidney transplant recipients. Methods: This retrospective cohort analysis involved data from 305 kidney transplant recipients participating in 3 randomized trials receiving reduced dose cyclosporin A (CsA) combined with EVR 0.75 mg BID (CSA/EVR 0.75 , N = 32) or 1.5 mg BID (CSA/EVR 1.5 , N = 31), reduced dose tacrolimus (TAC) combined with EVR 1.5 mg BID (TAC 0.05 /EVR 1.5 , N = 83), standard dose TAC combined with EVR 1.5 mg BID (TAC 0.1 /EVR 1.5 , N = 93), and EVR 1.5 mg BID (EVR 1.5 , N = 66) with TAC introduction after day 5. The adequacy of the initial EVR dose, based on EVR whole blood trough between 3 and 8 ng/mL, was compared using first EVR blood concentrations obtained at day 3 after transplantation. Results: Recipient age, proportion of patients with diabetes mellitus, and proportion of grafts from living donors were different among the groups. Dose-corrected EVR concentrations were higher in patients receiving CsA than in those receiving TAC or no calcineurin inhibitors (6.7 ± 5.9 versus 5.4 ± 2.2 versus 2.4 ± 0.8 versus 2.5 ± 0.9 versus 2.2 ± 0.7, P = 0.000). No differences were observed comparing dose adjusted EVR concentrations combined with TAC or alone ( P = 0.073). The proportion of patients with EVR concentration below <3 ng/mL was lower when EVR was combined with CsA (25 versus 3 versus 43 versus 33 versus 50%, P = 0.000). Later introduction of TAC did not influence EVR concentrations. There were no differences in mean CsA concentrations comparing patients receiving EVR 0.75 or 1.5 mg BID (240 ± 143 versus 213 ± 105 ng/mL). On the other hand, mean TAC concentrations were higher according to the initial TAC dose regimen (6.4 ± 3.9 versus 9.8 ± 5.9 ng/mL). Conclusions: In de novo kidney transplant recipients, the choice of the initial dose of EVR should consider the type of calcineurin inhibitor to reach target EVR concentration within the first week in a higher proportion of patients, maximizing the efficacy/toxicity profile.