Treatment of acute cellular rejection with T10B9.1A-31 or OKT3 in renal allograft recipients.

T10B9.1A-31, a nonmitogenic immunoglobulin Mk monoclonal antibody that detects an epitope on the alpha/beta chains of the T cell antigen receptor (TCR alpha/beta), or OKT3, an anti-CD3 mAb, was employed in a randomized double-blind phase II clinical trial to treat biopsy-proven acute cellular renal allograft rejection. Two of the 40 patients initially selected for the protocol were considered to be nonevaluable. Analysis of the remaining 38 patients receiving both living related and cadaveric donor allografts revealed a patient survival of 100% and a graft survival of 97%. Primary rejection reversal was achieved in 18/19 (95%) patients treated with T10B9.1A-31 and in 20/21 (95%) of patients receiving OKT3. The two patients who did not respond to the first mAb responded to the crossover mAb. Rerejection occurred in 3/18 (17%) of patients treated with T10B9.1A-31 and in 3/20 (15%) treated with OKT3. The mean day of rejection reversal was 1.9 +/- 0.7 with T10B9.1A-31 and 3.37 +/- 1.21 with OKT3 treatment. The rise in mean serum creatinine after mAb administration and the mean creatinine on days 1 through 6 were significantly less in patients treated with T10B9.1A-31. Biopsy specimens analyzed for rejection revealed no significant difference between the T10B9.1A-31 and OKT3 cohorts. The mean serum creatinines at 30, 60, 180, and 360 days posttransplantation were the same for both groups. Significantly fewer febrile, respiratory, and untoward effects followed the first dose (day 0) and fewer febrile, gastrointestinal, and neurological side effects occurred with subsequent doses (days 1-9) in patients treated with T10B9.1A-31. Infectious complications occurred in 3/13 patients treated only with T10B9.1A-31, in 9/17 OKT3-treated patients, and in 4/8 patients treated with both mAb. Analysis of human antimouse antibody (HAMA) revealed that the development of HAMA with T10B9.1A-31 was similar to that of OKT3.