Fludarabine, Cytarabine, Busulphan, and Cyclophosphamide (FABC) as Conditioning Regimen in Hematopoietic Stem Cell Transplantation for Treatment of 92 Patients with Hematologic Malignancies.

Abstract 1147

Poster Board I-169

In the past twenty years, allogeneic hematopoietic stem cells transplantation (Allo-HSCT) has been accepted as the most effective treatment for many hematologic malignancies. However, the successful rate of allo-HSCT has been limited by transplantation-related mortality and malignancies relapse, no matter using traditional intensity conditioning or reduced-intensity conditioning. In this study, we presented ninety-two patients with hematopoietic malignancies received fludarabine combinasion with modified Bu/Cy (FABC) conditioning regimen before allogeneic hematopoietic stem cell transplantation.

Ninety-two patients with hematological malignancies (58 males, 34 females) ranged in age from 14 to 50 (median 28) years. These patients were diagnosed with acute lymphoblastic leukemia (ALL, n=30), acute myelogenous leukemia(AML, n=24), chronic myelogenous leukemia (CML, n=33; CP, n=27; CML-AP, n=5; CML-BC, n=1), myelodysplastic syndrome ( MDS, n=3), chronic myelomonocytic leukemia (CMML, n=1), and one patient coexisted chronic myelomonocytic leukemia and T lymphoblast cell lymphoma. Fifty-five (59.8%) patients were at high risk. From June 2004 to October 2008, 92 patients gave their informed consent and received conditioning regimen with fludarabine-based modified Bu/Cy (FABC conditioning regimen) in allo-HSCT. The FABC regimen consist of cytarabine 2.0 g/ m² on day -9, busulphan (Bu) 3.2 mg/kg per day for intravenous on days -8 to day-6, followed by cyclophosphamide (Cy) 60 mg/kg per day on days -5 and day-4, combined fludarabin 30 mg/m² per day for three consecutive days, on days -6 to day-4, and Me-CCNU (1-(2-Chloroethyl)-3-(4-ethylnitrobiphenyl Cylohexyl4)-1- Nitrosourea) 250 mg/m² on day -3. Graft-versus-host-disease(GVHD) prophylaxis consisted of cyclosporine A, short-term MTX and Mycophenolate Mofefil (MMF 1.0g/day, on d-8 to d-1). Anti-T-lymphocyte globulin (2.5 mg·kg^-1·d ^-1, on d-3 to d-1) was added to patients with mismatched sibling or unrelated donors.

Follow-up was performed on 30 December, 2008. Ninety-two patients engrafted successfully, the median time for ANC >0.5×10⁹/L was 12 (8 to 22) days, and for BPC > 20×10⁹/L was 12 (7 -32) days. Detected by short tandem repeat (STR)-PCR, complete donor chimerism was comfirmed in all patients on day +21 or day+30. The incidence of acute GVHD was 25% (23/92), and grades 3 to 4 acute GVHD developed in 8 (8.7%) of 92 patients with in 100 days after HSCT. Chronic GVHD developed in 40(47.6%) of 84 patients who were alive more than 100 days after HSCT, and the incidence of extensive cGVHD was 35.7%(30/84). The transplant related mortality (TRM) was 19.6% (18/92), mainly from severe infection (n=7), acute or chronic GVHD (n=5), transplant associated-microangiopathy (n=2), diffusion alveolar hemorrhage (n=2), and post-transplant lymphoproliferative disorders (n=2). With a median follow-up of 16.2(1.5 to 54.5) months, 70 (76.1%) of the 92 patients were alive and 67(72.8%) were disease-free. The probabilities of OS at 1 year and 2 years was 80% and 72.5%, and DFS was 79.1% and 71.4%, respectively. These results suggest that the fludarabine-based modified Bu/Cy conditioning regimen (FABC) should reduce severe acute GVHD and accelerate hematopoietis resconsition without increasing chronic GVHD and lower leukemia relapse rates even in high-risk patients.

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