Matched and mismatched allogeneic stem-cell transplantation from unrelated donors using combined graft-versus-host disease prophylaxis including rabbit anti-T lymphocyte globulin

Purpose : With improved HLA-typing techniques, it is presently unclear what degree of identity is necessary for successful unrelated-donor stem-cell transplantation (UD SCT). Here, we describe the outcome after matched and mismatched UD SCT using a graft-versus-host disease (GVHD) prophylaxis including high-dose rabbit anti-T lymphocyte globulin (ATG). Patients and Methods: One hundred adult patients (median age, 37 years; range, 17 to 65 years) with hematologic malignancies underwent transplantation in early disease (first complete remission [CRI] or first chronic phase [CP1]; n = 34) or in advanced disease (second complete remission or second chronic phase, no remission, refractory; n = 66) with nondepleted bone marrow (n = 87) or peripheral-blood- derived (n = 13) stem cells from an HLA-A, HLA-B, HLA-DRB1*, or HLA-DQB1* identical (n = 75) or mismatched (one antigen, n = 21; two to three antigens, n = 4) unrelated donor. GVHD prophylaxis consisted of rabbit ATG before transplantation in addition to cyclosporine and short-course methotrexate. Results: The cumulative incidence of acute GVHD degreesII-degreesIV was 21% (95% confidence interval (CI), 14% to 33%) and 20% (95% Cl, 9% to 44%) and acute GVHD degreesIII-degreesIV was 5.3% (95% Cl, 2% to 14%) and 4% (95% Cl, 0.6% to 28%) in HLA-matched and HLA-mismatched transplantations, respectively. The risk for extensive chronic GVHD was 43% (95% Cl, 32% to 59%) and 44% (95% CI, 26% to 75%) for HLA-matched and HLA-mismatched patients, respectively. The risk of relapse at 4 years was 17% (95% Cl, 79/6 to 43%) and 43% (95% Cl, 31% to 60%) for CR1/CP1 and advanced disease patients, respectively. With a median follow-up of 1,068 days (range, 12 to 1,958 days), 3-year disease-free and overall survival for patients who underwent transplantation in CR1/CP1 was 63% (95% Cl, 46% to 81%) and 75% (95% Cl, 59% to 90%), respectively; and for patients with advanced disease, it was 34% (95% CI, 22% to 46%) and 39% (95% CI, 25% to 53%), respectively. Conclusion: A certain degree of one antigen mismatching may not compromise the outcome after UD SCT when using this rabbit ATG in addition to standard GVHD prophylaxis regimen. (C) 2003 by American Society of Clinical Oncology.