Mobilization and Collection of Peripheral Blood Stem Cells in Patients With Fanconi Anemia Using G-CSF and Plerixafor

Fanconi anemia is an autosomal recessive disease with an average survival of around 24 years old. The number of cells producted by bone marrow decreases around 5-10 years old. Hematological symptoms occur around 7 years old. 80% of patients with Fanconi anemia have clinical signs of bone marrow failure in the first decade of life. Generally macrocytosis is the first noticeable sign. Then it leads to thrombocytopenia, anemia and pancytopenia. Epidemiologic studies show that nearly all of the patients will have medullar aplasia before 40 years old, which is then the first cause of mortality. It must be emphasized that these complications may occur simultaneously for the same patient, so joint therapeutic intervention is needed. There is no basic treatment. Some currently used treatments cure cytopenias. These treatments involve blood transfusion, oral androgen, hematopoietic growth factor administration, such as Epo and G-CSF to treat anemia and neutropenia. These treatments are not curative. Hematopoietic stem cell transplantation is the only treatment able to restore permanently hematopoiesis. However, this treatment leads to a high level risk of developing solid tumors and other complications. All these data justify of developing a stem cells gene therapy treatment using a lentiviral vector expressing wild-type FANCA gene under CIBER promoter. Three studies have shown the potential number of cells to be mobilized in patients with Fanconi anemia. The aim is first, to show if administering G-CSF with plerixafor may lead to collect enough cells to potentially perform a gene therapy graft. Secondly the study will assess the tolerance, the stem cells' mobilization kinetic and collected cells' biological features. This study will be performed in Necker Children Hospital. 8 patients will be enrolled in order to reach 5 treated patients and to analyse how many injections and days are required to reach the cells' number goal. Sequential blood samples of patients will be drawn to monitor complete blood count (CBC), platelet, CD34+ cells rate and stem cells phenotype. The clinical and biological data will be anonymously entered in a electronic case report by the investigators up to the end of the study.