One-month prophylactic use of OKT3 in cadaver kidney transplant recipients

Fifty-five recipients of first cadaveric renal allografts were randomly assigned to three treatment groups in order to compare the safety and efficacy of a mouse antihuman T cell monoclonal antibody (OKT3) given prophylactically for a one-month period. This long period of administration was made possible by concomitant administration of azathioprine. The immune response against the foreign immunoglobulin was thus delayed and decreased in both intensity and severity, and OKT3 treatment could be given during almost the entire month in the majority of patients. The 18 patients who were enrolled in this treatment group had significantly (P less than 0.01) fewer rejection episodes during the first month posttransplantation than the 19 patients allocated to the high-dose (HD) steroid control group or the 18 patients allocated to the low-dose (LD) control group. Actual 2-year as well as actuarial 4-year graft survival rates were 89% in the OKT3 group, whereas they were 70% and 67% respectively in the steroid control groups. Four-year serum creatinine levels were normal and doses of steroids and other immunosuppressive agents were lower in the OKT3 group as compared with the control groups. Tolerance to OKT3 was good, and while viral infections were more frequently observed in OKT3 treated patients, the total number and the severity of infectious episodes were similar in all groups. The combination of one-month OKT3 plus azathioprine prophylaxis followed by conventional azathioprine plus low-dose steroid maintenance produced very satisfactory long-term results comparable to the best results now being obtained with cyclosporine regimens.