#3440 TOCILIZUMAB INDUCTION THERAPY IN KIDNEY TRANSPLANTATION

Abstract Background and Aims Antibody induction therapy is frequently used as an adjunct to the maintenance immunosuppression in adult kidney transplant recipients (KTRs). There are few comparisons of antibody induction therapy allowing early glucocorticoid withdrawal in KTRs. The purpose of the present study was to compare induction therapy involving tocilizumab with the most commonly used induction regimens in patient populations at either high immunologic risk or low immunologic risk. Method In this prospective study, we randomly assigned patients to receive tocilizumab or conventional induction therapy such as basiliximab. Patients were stratified according to acute rejection risk, with a high risk defined by a repeat transplant, a peak or current value of panel-reactive antibodies of 30% or more. The 102 high-risk patients received tocilizumab (one dose of 8 mg/kg, in 52 patients) or basiliximab (a total of 40 mg over 4 days, in 50 patients). The 113 low-risk patients received tocilizumab (one dose of 8 mg/kg, in 62 patients) or basiliximab (a total of 40 mg over 4 days, in 51 patients). All patients received tacrolimus and mycophenolate mofetil and underwent a 10-days glucocorticoid (prednisone) taper in a regimen of early steroid withdrawal. The primary end point was biopsy-confirmed acute rejection at 6 months and 12 months. Patients were followed for 2 years for safety and efficacy end points. Results The rate of biopsy-confirmed acute rejection was significantly lower in the tocilizumab group than in the basiliximab group at both 6 months (5.3% vs. 10.9%, P<0.01) and 12 months (7.9% vs. 12.9%, P<0.01). At 2 years, the rate of biopsy-confirmed acute rejection in low-risk patients was lower with tocilizumab than with basiliximab (9.7% vs. 17.7%, P<0.05), but among high-risk patients, no significant difference was seen between tocilizumab and basiliximab (19.2% vs. 16.0%, P = 0.68). Adverse-event rates were similar among all four treatment groups. Conclusion By the first year after transplantation, biopsy-confirmed acute rejection was less frequent with tocilizumab than with conventional therapy. The apparent superiority of tocilizumab with respect to early biopsy-confirmed acute rejection was restricted to patients at low risk for transplant rejection; among high-risk patients, tocilizumab and basiliximab had similar efficacy. Further randomized and controlled studies are needed to support these results.