Evaluating the state of the science for adeno-associated virus integration: An integrated perspective

Denise E Sabatino; Frederic D Bushman; Randy J Chandler; Ronald G Crystal; Beverly L Davidson; Ricardo Dolmetsch; Kevin C Eggan; Guangping Gao; Irene Gil-Farina; Mark A Kay; Douglas M McCarty; Eugenio Montini; Adora Ndu; Jing Yuan; American Society of Gene and Cell Therapy (ASGCT) Working Group on AAV Integration

doi:10.1016/j.ymthe.2022.06.004

Evaluating the state of the science for adeno-associated virus integration: An integrated perspective

Mol Ther. 2022 Aug 3;30(8):2646-2663. doi: 10.1016/j.ymthe.2022.06.004. Epub 2022 Jun 10.

Authors

Affiliations

¹ The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Division of Hematology, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA. Electronic address: dsabatin@pennmedicine.upenn.edu.
² Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
³ National Human Genome Research Institute, NIH, Bethesda, MD, USA.
⁴ Department of Genetic Medicine, Weill Medical College of Cornell University, New York, NY, USA.
⁵ The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
⁶ uniQure N.V., Amsterdam, the Netherlands.
⁷ BioMarin Pharmaceutical Inc, San Rafael, CA, USA.
⁸ Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
⁹ ProtaGene CGT GmbH, Heidelberg, Germany.
¹⁰ Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA.
¹¹ NeuroGT, Inc., Durham, NC, USA.
¹² San Raffaele Telethon Institute for Gene Therapy, IRCCS San Raffaele Scientific Institute, Milan, Italy.
¹³ BridgeBio Pharma, Inc., Palo Alto, CA, USA.
¹⁴ Drug Safety Research and Development, Pfizer Inc., Cambridge, MA, USA.

Abstract

On August 18, 2021, the American Society of Gene and Cell Therapy (ASGCT) hosted a virtual roundtable on adeno-associated virus (AAV) integration, featuring leading experts in preclinical and clinical AAV gene therapy, to further contextualize and understand this phenomenon. Recombinant AAV (rAAV) vectors are used to develop therapies for many conditions given their ability to transduce multiple cell types, resulting in long-term expression of transgenes. Although most rAAV DNA typically remains episomal, some rAAV DNA becomes integrated into genomic DNA at a low frequency, and rAAV insertional mutagenesis has been shown to lead to tumorigenesis in neonatal mice. Currently, the risk of rAAV-mediated oncogenesis in humans is theoretical because no confirmed genotoxic events have been reported to date. However, because insertional mutagenesis has been reported in a small number of murine studies, there is a need to characterize this genotoxicity to inform research, regulatory needs, and patient care. The purpose of this white paper is to review the evidence of rAAV-related host genome integration in animal models and possible risks of insertional mutagenesis in patients. In addition, technical considerations, regulatory guidance, and bioethics are discussed.

Keywords: AAV; bioethics; clonal expansion; genome integration; genotoxicity; hepatocellular carcinoma (HCC); insertional mutagenesis; next-generation sequencing; oncogenicity risk; recombinant AAV (rAAV).

Publication types

Review

MeSH terms

Animals
Dependovirus* / genetics
Genetic Vectors* / genetics
Humans
Mice
Mutagenesis, Insertional
Plasmids
Transgenes
Virus Integration