A Novel Reduced Intensity Conditioning Can Induce a High Incidence of Sustained Donor Engraftment After Double Unit Cord Blood Transplantation (CBT) without Anti-Thymocyte Globulin

• Published in: Blood 2010-11, Vol.116 (21), p.2351-2351
• Main Authors: Ponce, Doris M, Sauter, Craig, Lubin, Marissa, Gonzales, Anne Marie, Heller, Glenn, Castro-Malaspina, Hugo, Giralt, Sergio, Kernan, Nancy A., Papadopoulos, Esperanza B., Scaradavou, Andromachi, Barker, Juliet N.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V116.21.2351.2351

Abstract 2351 CBT can be curative for patients with high-risk hematologic malignancies. However, patients of older age, those with extensive prior therapy, or significant co-morbidities may not tolerate high-dose myeloablative conditioning. Reduced intensity (RI) or non-myeloablative (NMA) conditioning has been successfully used in CBT, especially in patients with lymphomas. However, patients with myeloid malignancies without extensive prior therapy have an increased risk of graft rejection following NMA CBT. Further, the addition of anti-thymocyte globulin (ATG) to enhance engraftment increases the risk of serious infections and Epstein-Barr virus post-transplant lymphoproliferative disease, and could increase the risk of relapse. Therefore, we investigated the efficacy and safety of a novel ATG-free RI conditioning prior to double unit CBT in patients with acute leukemias and myelodysplasia with the hypothesis that this regimen can induce a high incidence of sustained donor engraftment. Conditioning consisted of cyclophosphamide 50 mg/kg (day -6), fludarabine 30 mg/m2/day × 5 (days -6 to -2), thiotepa 5 mg/kg/day × 2 (days -5 and -4), and total body irradiation 200 cGy × 2 (days -2 and -1). All patients received cyclosporine-A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Between 10/01/07-04/30/10, 20 patients were transplanted. The median age was 56 years (range 18–69). Thirteen (65%) had AML (9 CR1, 4 CR2), 4 (20%) had ALL (3 CR1, 1 CR3), and 3 (15%) had MDS (with one patient also having follicular lymphoma). The majority had high-risk disease. Indications for RI conditioning were the risk factors for transplant-related mortality (TRM) with high-dose conditioning of age ≥50 years, and/or extensive prior therapy, and/or significant co-morbidities. Thirteen patients had only 1 of these risk factors, whereas 7 had ≥2 risk factors. Units were predominantly 4–5/6 HLA-matched to the recipient (one 6/6, twenty-four 5/6, fifteen 4/6). The median infused cell doses of the larger units were 2.7 × 107 total nucleated cells/kg (range 1.46–5.56) and 0.95 × 105 CD34+ cells/kg (range 0.35–3.32), and 1.89 × 107/kg total nucleated cells/kg (range 1.42–2.47) and 0.59 × 105/kg CD34+ cells/kg (range 0.18–1.52) for the smaller units, respectively. The cumulative incidence of sustained donor engraftment at day 45 was 95% (95%CI: 81–100). The single patient with graft failure was 100% donor in the day 21 bone marrow, but died early post-transpla