Sequential treatment for allogeneic hematopoietic stem cell transplantation in Fanconi anemia with acute myeloid leukemia

Fanconi anemia is a rare and heterogeneous inherited disorder. The natural history of FA is characterized by marrow failure and a risk for clonal evolution. Evolution to acute myeloid leukemia is the main cause of premature mortality. Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) is considered the treatment of choice in this situation but the evolution is usually poor post-HSCT (due to treatment-related mortality). From August 2006 to December 2011, 6 consecutive patients with FA who received a sequential treatment with chemotherapy and reduced-intensity conditioning for clonal evolution in four different French institutions were reviewed. Five patients presented an AML and one a myelodysplastic syndrome. The sequential strategy consisted of a pre-transplant chemotherapy by fludarabine 30 mg/m2/d 5 days and cytarabine 1gr/m2x2/d 5 days with granulocyte-colony stimulating factor injections (FLAG) followed early after by a reduced-intensity conditioning [4 days cyclophosphamide 10 mg/kg , 4 days fludarabine 30 mg/m2, 2 days anti-thymocyte globulin (3.75 mg/kg) and TBI (2 Gy)]. The source of stem cells was cord blood for three patients (HLA 5/6 for 2 and 4/6 for one) and bone marrow of unrelated donors for others (HLA 9/1O for one and 10/10 for two). Graft versus host disease prophylaxis consisted in cyclosporine plus MMF. Median age of the patients at HSCT was 20.5 years (5-28). Pre-transplant chemotherapy and conditioning regimen were well tolerated. The median time between chemotherapy and the date of HSCT was 30 days (when neutrophil count reached values below 500/microL). All patients engrafted. Median time to engraftment was 26 days (14,21,25,27,31,35) for neutrophils and 29 days for platelets(21,25,29,29,35,42). Donor chimerism was complete at day 100 for 5 patients. Septicemias were encountered in three patients (Staphylococcus, Enterobacter, and Candida) at 1, 3 and 4 months after HSCT, respectively. One patient developed a diarrhea to Campylobacter jejuni one month after HSCT and another patient underwent meatotomy. Acute GvHD (1 grade I of the skin and 1 grade II in the gastrointestinal tract ) occurred in 2 patients . Both responded to steroid therapy. Chronic GvHD occurred in two patients (involve the skin). After a median follow-up (FU) of 30 months (5-72), all patients are still alive in complete remission from the clonal evolution. With a median FU of 30 months, all patients are alive and free from their original AML or MDS. The number of patients is little but the usual evolution is very poor post-HSCT in this particular situation. We thus believe this study supports the use of a sequential strategy (FLAG and RIC HSCT) in FA patients with AML or MDS.