Fludarabine (Flu) Based Cytoreductive Regimen and T-Cell Depleted Grafts from Unrelated or Mismatched Related Donors for the Treatment of High Risk Patients with Fanconi Anemia (FA).

Between 05/98 and 06/04, 15 consecutive patients with FA received hematopoietic stem cell transplants (SCT) from alternative donors at our Center. There were 7 males and 8 females aged 5 to 24 years (median 11.5). Hematologic diagnoses included aplastic anemia (AA) (N=5), myelodysplastic syndrome (MDS) in RAEB (N=4), RAEBT (N=1) or acute myelogenous leukemia (AML) (N=5). High risk features included: Age > 20 years (n=4), prior multiple transfusions (n=11), prior androgen treatment (n=12), prior infections (n=10), or advanced MDS or AML (n=9). Eight pts had related mismatched donors transplants with respective matching at 3/6 (6/10), 4/6 (6/10), 4/6 (7/10) (n=2)), 5/6 (8/10) (n=3) and 5/6 (9/10) HLA-antigens. Seven pts had unrelated donors transplants with respective matching at 5/6 (7/10), 5/6 (8/10) (n=2), 5/6 (9/10) and 6/6 (10/10) (n=3) HLA-antigens. Cytoreduction included single dose total body irradiation (SDTBI) (450 cGy), fludarabine (Flu) (30 mg/m² x 5) and cyclophosphamide (Cy) (10 mg/Kg x 4). Immunosuppression included rabbit anti-thymocyte globulin (Thymoglobulin) and tacrolimus for all patients. Grafts were G-CSF mobilized CD34+ and E-rosette negative (E-) peripheral blood stem cell transplants for 12 pts and soybean agglutinin negative (SBA-) and E-rosette negative marrow transplants for 3 pts. Cell doses of the grafts were 1.5 – 29.6 x 10⁶ CD34 cells/Kg and 0 – 26 x 10³ CD3 cells/Kg. As evidenced by RFLP or FISH, all 15 evaluable pts were fully engrafted and complete chimeras. Fourteen pts were evaluable for graft-versus-host disease (GvHD). GvHD of the skin and of the gut was suspected in two pts but resolved completely prior to immunosuppressive treatment. With a median follow-up of 2.5 years (range 0.2–6), 13 of 15 pts are alive and 11 of 15 are alive disease-free. There were two deaths: one pt died from sepsis/ARDS at 2 months post SCT and one pt from pneumonitis/ARDS and EBV-infection 6 months post SCT. Three pts relapsed (MDS-RAEB x 1 – AML x 2): One pt relapsed 7 months post transplant, received a 2^nd transplant from the same donor following busulfan and Flu and is alive, disease-free 18 months post SCT, while the other two pts are awaiting a second SCT. In summary, this cytoreductive regimen used with T-cell depleted stem cell transplants from unrelated or HLA-mismatched related donors for the treatment of high risk patients with Fanconi anemia, results in rapid hematopoietic engraftment and lymphohematopoietic reconstitution with minimal GVHD and a high disease-free survival.