Stem cell transplantation for patients with Fanconi anemia with low-dose cyclophosphamide and antithymocyte globulins without the use of radiation therapy

In all, 22 patients with confirmed Fanconi anemia ( FA) underwent stem cell transplantation ( SCT) from HLA-matched, related donors at KFSHRC. Median age at SCT was 7.6 years ( range, 2.5 - 14.6 years). Conditioning regimen consisted of cyclophosphamide ( CY) 15 mg/ kg/ day intravenously ( i. v.) for 4 consecutive days, in addition to equine antithymocyte globulins ( ATG) given i. v. at 40 mg/ kg/ day for four doses pre- SCT. No radiation therapy was given. For graft- versus- host disease prophylaxis, we used cyclosporin at the standard doses; ATG was added at 20 mg/ kg/ dose i. v. on days 2, 4, 6, 8, 10, and 12 post- SCT ( total of six doses). All patients engrafted and are alive and transfusion independent with a median follow- up time of 20.2 months ( range, 3.3 - 59 months). One patient however developed a decrease in her WBC and platelet count. Her work- up revealed slightly hypocellular bone marrow, and a series of chimerism studies over 1 year confirmed that she has stable mixed chimerism; she remains transfusion independent. We conclude that low- dose CY without radiation therapy can be used satisfactorily in the conditioning of patients with FA undergoing related SCT.