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Author Notes:

Christopher B. Doering, PhD, 2015 Uppergate Drive, Emory Children’s Center, Rm 450, Atlanta, GA 30322, USA. cdoerin@emory.edu

Conceptualization, A.L.R., H.T.S., S.C., and C.B.D.; methodology, C.P., G.D., K.A.K., J.S.A., H.T.S., S.C., and C.B.D.; investigation, A.L.R., C.P., T.S.L., K.A.K., J.T.Z., and G.D.; validation, A.L.R.; formal analysis, A.L.R.; resources, J.A.; writing – original draft, A.L.R.; writing – review & editing, A.L.R., H.T.S., S.C., and C.B.D.; visualization, A.L.R.; supervision, S.C. and C.B.D.; funding acquisition, H.T.S., S.C., and C.B.D.

C.B.D. and H.T.S. are co-founders of Expression Therapeutics and own equity in the company. Expression Therapeutics owns the intellectual property associated with ET3. G.D. is an employee of Expression Therapeutics and owns equity in the company. S.C. serves on the advisory committee on emapalumab for Sobi. The terms of this arrangement have been reviewed and approved by Emory University in accordance with its conflict of interest policies. A.L.R., C.P., T.S.L., K.A.K., J.T.Z., and J.S.A. declare no competing interests.

Subject:

Research Funding:

This work was supported by funding from the National Institutes of Health (NIH)/National Heart, Lung and Blood Institute (NHLBI) (C.B.D. and H.T.S.) grant number U54 HL141981 and Hemophilia of Georgia (C.B.D. and H.T.S.).

Research reported in this publication was supported in part by the Pediatrics/Winship Flow Cytometry Core of Winship Cancer Institute of Emory University, Children's Healthcare of Atlanta, and NIH/NCI under award number P30CA138292.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Graphical abstract and original schematic figures created with https://biorender.com/.

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Medicine, Research & Experimental
  • Research & Experimental Medicine
  • HIGH-LEVEL EXPRESSION
  • VERSUS-HOST-DISEASE
  • PORCINE FACTOR-VIII
  • ANTITHYMOCYTE GLOBULIN
  • MONOCLONAL-ANTIBODIES
  • ENABLES SAFE
  • TRANSPLANTATION
  • ALEMTUZUMAB
  • TRANSGENE
  • PROPHYLAXIS

Non-genotoxic conditioning facilitates hematopoietic stem cell gene therapy for hemophilia A using bioengineered factor VIII

Tools:

Journal Title:

MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT

Volume:

Volume 21

Publisher:

, Pages 710-727

Type of Work:

Article | Final Publisher PDF

Abstract:

Hematopoietic stem and progenitor cell (HSPC) lentiviral gene therapy is a promising strategy toward a lifelong cure for hemophilia A (HA). The primary risks associated with this approach center on the requirement for pre-transplantation conditioning necessary to make space for, and provide immune suppression against, stem cells and blood coagulation factor VIII, respectively. Traditional conditioning agents utilize genotoxic mechanisms of action, such as DNA alkylation, that increase risk of sterility, infection, and developing secondary malignancies. In the current study, we describe a non-genotoxic conditioning protocol using an immunotoxin targeting CD117 (c-kit) to achieve endogenous hematopoietic stem cell depletion and a cocktail of monoclonal antibodies to provide transient immune suppression against the transgene product in a murine HA gene therapy model. This strategy provides high-level engraftment of hematopoietic stem cells genetically modified ex vivo using recombinant lentiviral vector (LV) encoding a bioengineered high-expression factor VIII variant, termed ET3. Factor VIII procoagulant activity levels were durably elevated into the normal range and phenotypic correction achieved. Furthermore, no immunological rejection or development of anti-ET3 immunity was observed. These preclinical data support clinical translation of non-genotoxic antibody-based conditioning in HSPC LV gene therapy for HA.

Copyright information:

© 2021 The Authors

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/rdf).
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