title: Lentiviral hematopoietic cell gene therapy for X-linked adrenoleukodystrophy.
abstract: X-linked adrenoleukodystrophy (X-ALD) is a severe genetic demyelinating disease caused by a deficiency in ALD protein, an adenosine triphosphate-binding cassette transporter encoded by the ABCD1 gene. When performed at an early stage of the disease, allogeneic hematopoietic stem cell transplantation (HCT) can arrest the progression of cerebral demyelinating lesions. To overcome the limitations of allogeneic HCT, hematopoietic stem cell (HSC) gene therapy strategy aiming to perform autologous transplantation of lentivirally corrected cells was developed. We demonstrated the preclinical feasibility of HSC gene therapy for ALD based on the correction of CD34+ cells from X-ALD patients using an HIV1-derived lentiviral vector. These results prompted us to initiate an HSC gene therapy trial in two X-ALD patients who had developed progressive cerebral demyelination, were candidates for allogeneic HCT, but had no HLA-matched donors or cord blood. Autologous CD34+ cells were purified from the peripheral blood after G-CSF stimulation, genetically corrected ex vivo with a lentiviral vector encoding wild-type ABCD1 cDNA, and then reinfused into the patients after they had received full myeloablative conditioning. Over 3 years of follow-up, the hematopoiesis remained polyclonal in the two patients treated with 7-14% of granulocytes, monocytes, and T and B lymphocytes expressing the lentivirally encoded ALD protein. There was no evidence of clonal dominance or skewing based on the retrieval of lentiviral insertion repertoire in different hematopoietic lineages by deep sequencing. Cerebral demyelination was arrested 14 and 16months, respectively, in the two treated patients, without further progression up to the last follow-up, a clinical outcome that is comparable to that observed after allogeneic HCT. Longer follow-up of these two treated patients and HSC gene therapy performed in additional ALD patients are however needed to evaluate the safety and efficacy of lentiviral HSC gene therapy in cerebral forms of X-ALD.
authors.affiliation: INSERM UMR745, University Paris-Descartes, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Cartier
authors.forename: Salima
authors.initials: S
authors.lastname: Hacein-Bey-Abina
authors.forename: Cynthia C
authors.initials: CC
authors.lastname: Bartholomae
authors.forename: Pierre
authors.initials: P
authors.lastname: Bougnères
authors.forename: Manfred
authors.initials: M
authors.lastname: Schmidt
authors.forename: Christof Von
authors.initials: CV
authors.lastname: Kalle
authors.forename: Alain
authors.initials: A
authors.lastname: Fischer
authors.forename: Marina
authors.initials: M
authors.lastname: Cavazzana-Calvo
authors.forename: Patrick
authors.initials: P
authors.lastname: Aubourg
mesh_terms: D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000326:Adrenoleukodystrophy / Q000628:therapy*; D002648:Child; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D057809:HEK293 Cells; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000821:virology; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D008297:Male; D016896:Treatment Outcome
chemical_list: C115572:ABCD1 protein, human; D000074063:ATP Binding Cassette Transporter, Subfamily D, Member 1; D018528:ATP-Binding Cassette Transporters