Higher Incidence of Acute Rejection in Renal Transplant Recipients With Low Everolimus Exposure

Everolimus (EVL) has shown a potential to reduce nephrotoxicity associated with cyclosporine (CsA) while providing similar protection against rejection. We analyzed the incidence of acute rejection episodes (ARE) among 20 cadaveric renal transplant recipients treated with the combination of EVL + CsA. Immunosuppression consisted of basiliximab induction given pretransplant and on day 4 posttransplant; EVL at a starting dose of 1.5 mg/day followed by concentration control to trough levels of 3 to 8 ng/mL by day 7; CsA at a starting dose of 4 mg/kg per day and then concentration controlled with C2 monitoring (C2 500-700 ng/mL); and steroids in a tapering regimen to reach 5 mg by day 30. The overall incidence of ARE was 25%. On postoperative day 7, patients with ARE showed significantly lower mean EVL trough concentrations compared with those not experiencing ARE (NO ARE: 2.2 ± 2.1 ng/mL vs 4.8 ± 2.4 ng/mL) (P = .05). The CsA C2 values were close to the lower end of the target range on day 3 (583 ± 334 ng/mL). All rejecting grafts were functioning at 3 months posttransplantations, but mean serum creatinine was higher in the ARE group (ARE 2.2 ± 0.7 mg/dL vs 1.1 ± 0.2 NO ARE; P = .04). In conclusion, whenever EVL is used in combination with CsA to protect kidney transplant patients against the risk of acute rejection, a threshold of 3 ng/mL must be reached in the first week posttransplantation. We suggest careful monitoring of EVL exposure and increased EVL starting doses.