Haploidentical Transplantation in Severe Aplastic Anemia

A Research on Haploidentical Transplantation in Severe Aplastic Anemia Using Reduced-intensity Fludarabine-based Conditioning

This is a prospective case-control study on SAA patients treated with HSCT, order to further discuss and assess the safety, feasibility and effectiveness of HFD-HSCT which performed with reduced-intensity fludarabine-based conditioning regimen.Our findings would indicate that SAA patients who lack MSD benefited most if HFD-HSCT was performed with reduced-intensity fludarabine-based conditioning regimen, and our improved outcomes with HFD-HSCT may lead to a salvaged therapy and an expanded direct role for SAA in the future.

This group received treatment of matched sibling donor - hematopoietic stem cell transplantation (MSD-HSCT).

This group received treatment of haploid family donor - hematopoietic stem cell transplantation (HFD-HSCT).

Conditioning regimens: (A) Patients had SAA and PNH, or heavy transfusion (RBC≥25U), or failed rabbit ATG therapy, and received 0.8 mg/kg/6h busulfan (days -7 to -6), 30mg/m2/day fludarabine (days -5 to -2), 25 mg/kg/day cyclophosphamide (days -5 to -2) and 2.5 mg/kg/day r-ATG (days -5 to -2). (B) The other patients with SAA or VSAA received same procedure but without busulfan; Allogeneic HSC infusion: Doner BM cells were harvested to achieve a target mononuclear cell count (MNC) of 2-4 × 108 per kilogram of recipient weight. The target MNC from PB was 4-6× 108 per kilogram of recipient weight; Prophylaxis and treatment of GVHD: GVHD prophylaxis consisted of intravenous CSP 2-3 mg/kg/day in divided doses beginning on the day before transplantation (day -5) and the target concentration was adjusted to 150-250 ng/ml. The oral MMF dose was 20 mg/kg/day from day -1 and was tapered off after 1 months if no aGVHD was observed.

Conditioning regimens: (A) Patients had SAA and PNH, or heavy transfusion (RBC≥25U), or failed rabbit ATG therapy, and received 0.8 mg/kg/6h busulfan (days -7 to -6), 35mg/m2/day fludarabine (days -5 to -2), 25 mg/kg/day cyclophosphamide (days -5 to -2) and 2.5 mg/kg/day r-ATG (days -5 to -2). (B) The other patients with SAA or VSAA received same procedure but without busulfan; Allogeneic HSC infusion: Doner BM cells were harvested to achieve a target mononuclear cell count (MNC) of 2-4 × 108 per kilogram of recipient weight. The target MNC from PB was 4-6× 108 per kilogram of recipient weight; Prophylaxis and treatment of GVHD: GVHD prophylaxis consisted of intravenous CSP 2-3 mg/kg/day in divided doses beginning on the day before transplantation (day -5) and the target concentration was adjusted to 200-300 ng/ml. The oral MMF dose was 20 mg/kg/day from day -3 and was tapered off after 2 months if no aGVHD was observed.

Neutrophil engraftment was defined as the first of three consecutive days in which the neutrophil counts (ANC) exceeded 0.50 × 109/L, and platelet engraftment was defined as the first of five consecutive days in which the platelet count exceeded 20 × 109/L without transfusion. GF was classified as follows: (1) primary non-engraftment (failure to reach a neutrophil count of 0.5×109/L after transplant); (2) rejection (decrease in blood counts to < 0.5×109/L neutrophils, after achieving a neutrophil count of 0.5×109/L); (3) late graft failure (decrease of blood counts after day 100 to < 1.0×109/L neutrophils and < 30×109/L platelets).

The transplantation-related toxicity (TRT) was graded using the National Cancer Institute Common Toxicity Criteria for Adverse Events version 4.0. Organ damage due to GVHD or infectious complications were excluded.

Chimerism would be evaluated in recipient BM cells usually on days +30 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.

Chimerism would be evaluated in recipient BM cells usually on days +180 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.

Chimerism would be evaluated in recipient BM cells usually on days +100 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.

Chimerism would be evaluated in recipient BM cells usually on days +365 after HSCT using cytogenetic G-banding or fluorescence in situ hybridization. Sex-matched donor-recipient chimerism was assessed using PCR-based analyses of polymorphic minisatellite or microsatellite regions. HLA typing was performed for patients with HLA-haploidentical donors.

EFS was defined as survival with a response to therapy. Death, GF and relapse were considered as treatment failure. EFS was defined as survival with a response to therapy. Death, GF and relapse were considered as treatment failure.

EFS was defined as survival with a response to therapy. Death, GF and relapse were considered as treatment failure.

EFS was defined as survival with a response to therapy. Death, GF and relapse were considered as treatment failure.

Inclusion Criteria: (i) Diagnosis of SAA, very SAA or SAA and paroxysmal nocturnal hemoglobinuria (PNH) according to the International Aplastic Anemia Study Group; (ii) SAA patients no response to previous IST; (iii) adequate performance status [Eastern Cooperative Oncology Group (ECOG) score 0-2]. Exclusion Criteria: (i) Congenital forms of aplastic anemia; (ii)Patients with any severe pulmonary, cardiac, liver, or renal diseases or active infection.