Ten-year follow-up of recipients of a kidney or heart transplant who received induction therapy with a monoclonal antibody against the interleukin-2 receptor.

Objectives: Twelve years ago, we performed two randomized clinical trials to investigate safety and efficacy of induction therapy with BT563, a highly potent murine monoclonal antibody against the interleukin-2 receptor after kidney and heart transplantation. We analyzed the long-term safety and efficacy data from all 120 patients who participated in the two randomized trials after kidney and heart transplantation 10 years ago.

Materials And Methods: One of these two trials was a randomized, double-blind, placebo-controlled trial, with 60 primary and secondary kidney allograft recipients (cadaveric and living-related donors). The control group was treated with the standard regimen at that time, consisting of cyclosporin and prednisone. In the study group, BT563 was added for 10 days. The second trial was a randomized, double-blind trial, with 60 recipients of a primary heart transplant. In that study, we compared induction therapy with BT563 with the standard regimen at that time, consisting of cyclosporin, prednisone, and OKT3 (both induction agents were given for 7 days).

Results: Patient survival in the kidney trial was excellent: in the BT563 group, 24 patients were alive (80%), and in the placebo, group 21 (70%) 10 years after transplantation. Also, graft survival was good: in the BT563 group, 63.3% of the kidneys (19/30) were functioning, in the placebo group, 72.4% (21/29) were functioning (P = 0.455). Also, in the heart study, patient (and graft) survival was excellent: 18 patients were alive in the BT563 group (58%), and in the OKT3 group, 21 (72%) patients were alive (P = ns). No increase in the incidence of malignancies was observed between patients treated with BT563 compared with the control groups. Patients following heart transplantation more often suffered from a malignancy than did patients after kidney transplantation (20/60 vs 10/59).

Conclusions: We report follow-up data on all patients participating in the two randomized trials, and our data reflect a total of 932 years of patient follow-up. Patient and graft survival appear to be excellent in both the BT563-treated patients and the control groups. BT563 treatment was not associated with an increased likelihood of developing infections or malignancies.