Preclinical development of lentiviral vector gene therapy for Diamond-Blackfan anemia syndrome.

Abstract

Diamond-Blackfan anemia syndrome (DBAS) is an inherited bone marrow failure disorder caused by haploinsufficiency of ribosomal protein genes, most commonly RPS19. Limited access to patient hematopoietic stem/progenitor cells (HSPCs) is a major roadblock to developing novel therapies for DBAS. We developed a novel self-inactivating third-generation RPS19-encoding lentiviral vector (LV), termed "SJEFS-S19", for DBAS gene therapy. To facilitate LV design, optimize transduction and assess potential therapeutic efficacy, we leveraged a human cellular model of DBAS based on heterozygous disruption of RPS19 in healthy donor CD34⁺ HSPCs. We show that SJEFS-S19 LV can rescue DBAS-associated defects in ribosomal RNA processing, erythropoiesis and competitive bone marrow repopulation. Transduction of RPS19^+/- CD34⁺ HSPCs with SJEFS-S19 LV followed by xenotransplantation into immunodeficient mice generated a polyclonal HSPC population with normal multi-lineage differentiation and a diverse integration site profile resembling that of clinically proven LVs. Overall, these preclinical studies demonstrate the safety and efficacy of SJEFS-S19, a novel LV for future DBAS gene therapy.