THE DURATION OF ADMINISTRATION OF MONOCLONAL-ANTIBODY OKT3 FOR INDUCTION IMMUNOSUPPRESSION AFTER HEART-TRANSPLANTATION

The effective treatment of refractory allograft rejection with murine antihuman monoclonal antibody muromonab-CD3 (OKT3) and of patients wit h renal dysfunction has led to its use as induction therapy. The optim al protocol for OKT3 prophylaxis remains to be established. We compare d 59 patients consecutively transplanted with the total orthotopic tec hnique between 1/92 and 5/94. The first 21 patients were treated with OKT3 for 14 days, the next 19 for 10 days, and the last 19 for 7 days. Patients operated with different surgical techniques or other inducti on treatment were exluded. We compared length of stay (total and ICU), time to first rejection, rejection incidence and infection incidence (cytomegalovirus separately), and survival. Preoperative characteristi cs were similar except for significantly younger age in the 10-day gro up (p=0.04). Preoperative hemodynamic parameters were similar except f or a significantly higher left-ventricular ejection fraction (21 %) in the 7-day group. Length of stays in the ICU and hospital were similar for the three groups (p = NS). Freedom from cellular rejection was lo wer with the 7 days course (p = 0.02), but freedom from humoral reject ion was slightly higher (p = 0.11). However, patients in the 7-day gro up required treatment for rejection less frequently than patients in t he other two groups (95 % untreated at 2 months vs. 43 % in the 14-day and 53% in the 10-day group; p = 0.002). There were no differences in incidences of infections, including cytomegalovirus. Survival was sim ilar between the groups. There was one death in the 14-day and 1 in th e 10-day group, both due to rejection. In conclusion, OKT3 therapy can be reduced safely to 7 days with a higher overall incidence of reject ion but no increased necessity to treat for rejection, and no differen ce in infection incidence.