Comparison of two drug regimens upon clinical outcome among renal transplant recipients with positive flow cytometric crossmatches.

Renal transplant recipients with positive flow cytometric crossmatches (FCXM) face greater risk of early rejection and graft failure. It is clear that the pharmacologic needs of this high risk group have not been identified. We retrospectively compared the impact of two drug regimens upon early rejection and 5 yr actuarial survival among 324 primary cadaveric transplant recipients with positive and negative FCXM. Patients received either Regimen I (OKT3 induction, cyclosporine and steroids) or Regimen II (mycophenolate mofetil with cyclosporine or Prograf). Recipient gender, age, disease etiology, ethnic distribution and cytotoxic panel reactive antibody (PRA) were equivalent between regimens (p=ns). With Regimen I, the incidence of rejection was greater for FCXM positive vs. FCXM negative patients (51 vs. 21%, p=0.001). In contrast, with Regimen II the incidence of rejection for FCXM positive and FCXM negative patients was equivalent (18 vs. 12%, p=ns) and lower than patients treated with Regimen I (p < 0.01). Ethnic variation was only observed with Regimen I in which African Americans with positive FCXM had more rejections than Caucasians (60 vs. 45%, p < 0.05). Five-year actuarial survival was lower for FCXM positive vs. FCXM negative patients treated with Regimen I (40 vs. 75%, p=0.0006) or Regimen 2 (60 vs. 90%, p=0.001). Allograft survival was equivalent (p=ns) among FCXM positive individuals receiving Regimen I or II. However, allograft survival among FCXM negative individuals improved with Regimen II (p < 0.05). Ethnic variation in survival was not observed with either regimen (p=ns).