Retrieval of vector integration sites from cell-free DNA

• Published in: Nature medicine Vol. 27; no. 8; pp. 1458 - 1470
• Main Authors: Cesana, Daniela, Calabria, Andrea, Rudilosso, Laura, Gallina, Pierangela, Benedicenti, Fabrizio, Spinozzi, Giulio, Schiroli, Giulia, Magnani, Alessandra, Acquati, Serena, Fumagalli, Francesca, Calbi, Valeria, Witzel, Maximilian, Bushman, Frederic D., Cantore, Alessio, Genovese, Pietro, Klein, Christoph, Fischer, Alain, Cavazzana, Marina, Six, Emmanuelle, Aiuti, Alessandro, Naldini, Luigi, Montini, Eugenio
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.08.2021; Nature Publishing Group
• Subjects: 631/61/2300/1514; 692/308/575; Biomedical and Life Sciences; Biomedicine; Biopsy; Blood cells; Blood circulation; Cancer Research; Deoxyribonucleic acid; DNA; DNA sequencing; Gene therapy; Genetic modification; Genetic vectors; Health aspects; Hematopoietic stem cells; Identification and classification; In vivo methods and tests; Infectious Diseases; Innovations; Integration; Metabolic Diseases; Molecular Medicine; Monitoring; Neurosciences; Nucleotide sequencing; Organs; Patients; Polymerase chain reaction; Safety; Stem cells; Telemedicine; Tracking; Tracking techniques; United States
• ISSN: 1078-8956; 1546-170X; 1546-170X
• DOI: 10.1038/s41591-021-01389-4

Gene therapy (GT) has rapidly attracted renewed interest as a treatment for otherwise incurable diseases, with several GT products already on the market and many more entering clinical testing for selected indications. Clonal tracking techniques based on vector integration enable monitoring of the fate of engineered cells in the blood of patients receiving GT and allow assessment of the safety and efficacy of these procedures. However, owing to the limited number of cells that can be tested and the impracticality of studying cells residing in peripheral organs without performing invasive biopsies, this approach provides only a partial snapshot of the clonal repertoire and dynamics of genetically modified cells and reduces the predictive power as a safety readout. In this study, we developed liquid biopsy integration site sequencing, or LiBIS-seq, a polymerase chain reaction technique optimized to quantitatively retrieve vector integration sites from cell-free DNA released into the bloodstream by dying cells residing in several tissues. This approach enabled longitudinal monitoring of in vivo liver-directed GT and clonal tracking in patients receiving hematopoietic stem cell GT, improving our understanding of the clonal composition and turnover of genetically modified cells in solid tissues and, in contrast to conventional analyses based only on circulating blood cells, enabling earlier detection of vector-marked clones that are aberrantly expanding in peripheral tissues. A new approach called liquid biopsy integration site sequencing enables monitoring of genetically modified cells in solid tissues of patients receiving gene therapy.