Cited by 13Virus-based gene therapy researchCAR-T cell therapy researchCRISPR and Genetic Engineering

TEG001 Insert Integrity from Vector Producer Cells until Medicinal Product

Open access
Straetemans, Trudy, Janssen, Anke, Jansen, Koen, Doorn, Ruud, Aarts, Tineke, van Muyden, Anna D.D., Simonis, Marieke, Bergboer, Judith +3 more·2020·Molecular Therapy

Abstract

Despite extensive usage of gene therapy medicinal products (GTMPs) in clinical studies and recent approval of chimeric antigen receptor (CAR) T cell therapy, little information has been made available on the precise molecular characterization and possible variations in terms of insert integrity and vector copy numbers of different GTMPs during the complete production chain. Within this context, we characterize αβT cells engineered to express a defined γδT cell engineered to express a defined γδT receptor (TEG) currently used in a first-in-human clinical study (NTR6541). Utilizing targeted locus amplification in combination with next generation sequencing for the vector producer clone and TEG001 products, we report on five single-nucleotide variants and nine intact vector copies integrated in the producer clone. The vector copy number in TEG001 cells was on average a factor 0.72 (SD 0.11) below that of the producer cell clone. All nucleotide variants were transferred to TEG001 without having an effect on cellular proliferation during extensive in vitro culture. Based on an environmental risk assessment of the five nucleotide variants present in the non-coding viral region of the TEG001 insert, there was no altered environmental impact of TEG001 cells. We conclude that TEG001 cells do not have an increased risk for malignant transformation in vivo.

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Integrity signals

Registry

Crossref · 10.1016/j.ymthe.2019.11.030

Cites

59 of 59 references verified0 citation errors · 0 not checkable

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  • An insufficient number of vector copies may result in low or absent CAR receptor expression, compromising product efficacy.

    “Therapeutic Efficacy: an insufficient number of vector copies may result in low or absent CAR receptor expression, compromising product efficacy [27–30].”

    From Harmonisation of quality control tests for academic production of CAR-T cells: a position paper from the WP-bioproduction of the UNITC consortium (2025) · cites this paper as [30]

    The Discussion (page unavailable) suggests that higher vector copy numbers may be needed for TEG001 receptor expression because its introduced TCR competes for CD3 molecules. It explicitly contrasts TEG001 with CAR T products; it does not say that insufficient copies cause low or absent CAR expression or compromise product efficacy. (LLM, conf=0.76)

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  • An excessive number of vector copies can lead to CAR overexpression, increasing toxicity risks.

    “Safety: an excessive number of vector copies can lead to CAR overexpression, increasing toxicity risks.”

    From Harmonisation of quality control tests for academic production of CAR-T cells: a position paper from the WP-bioproduction of the UNITC consortium (2025) · cites this paper as [30]

    The Introduction links higher vector copy numbers to potential safety risks, and the Discussion says CAR T products have generally stayed below a five-copy threshold. The paper does not say that excess copies cause CAR overexpression or that CAR overexpression increases toxicity; its transgene-copy-number section says it is unclear whether more integration sites per cell add to genotoxicity risk. The supplied passages have section labels but no page numbers. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • A high vector copy number raises the risk of insertional mutagenesis, where the vector integrates into genomic regions that could activate proto-oncogenes or disable tumor suppressor genes.

    “Additionally, a high copy number raises the risk of insertional mutagenesis, where the vector integrates into genomic regions that could activate proto-oncogenes or disable tumor suppressor genes [28–31].”

    From Harmonisation of quality control tests for academic production of CAR-T cells: a position paper from the WP-bioproduction of the UNITC consortium (2025) · cites this paper as [30]

    The Introduction (page unavailable) discusses potential risks from integration sites and higher copy numbers, and gives an example of a gene disrupted by integration. But “Transgene Copy Number in TEG001 Drug Product” (page unavailable) says it is unclear whether more integration sites per cell add to genotoxicity risk; it does not establish that high copy number raises that risk. The cited passages also do not state the proposed proto-oncogene or tumor-suppressor mechanism. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

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Research works printed but not linked: 2

  1. [7]7. [Kierkels, G.J.J., Scheper, W., Meringa, A.D., Johanna, I., Beringer, D.X., Janssen, A., Schif fl er, M., Aarts-Riemens, T., Kramer, L., Straetemans, T., et al. (2019). Identi fi cation of a tumor-speci fi c allo-HLA-restricted gd TCR. Blood Adv. 3 , 2870 -2882.](http://refhub.elsevier.com/S1525-0016(19)30556-8/sref7)
  2. [16]16. [Straetemans, T., Kierkels, G.J.J., Doorn, R., Jansen, K., Heijhuurs, S., Dos Santos, J.M., van Muyden, A.D.D., Vie, H., Clemenceau, B., Raymakers, R., et al. (2018). GMPGrade Manufacturing of T Cells Engineered to Express a De fi ned gd TCR. Front. Immunol. 9 , 1062.](http://refhub.elsevier.com/S1525-0016(19)30556-8/sref16)

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Authors
Straetemans, T., Janssen, A., Jansen, K., Doorn, R., Aarts, T., van Muyden, A. D. D., Simonis, M., Bergboer, J., de Witte, M., Sebestyen, Z., & Kuball, J.
Affiliations
  • Utrecht University (NL)
  • Cergentis (Netherlands) (NL)
Corresponding author
  • Straetemans, Trudy
  • Kuball, Jurgen
Venue
Molecular Therapy
Publisher
Elsevier BV
Published
2020-02
Volume
28
Issue
2
Pages
561-571
ISSN
1525-0016 (ISSN-L)
OpenAlex
W2996130480
Cited by
13
References
59
Citations by year
2026: 1 · 2025: 1 · 2023: 1 · 2022: 1 · 2021: 6 · 2020: 3
FWCI
1.51
Type
journal article
Language
en
Open access
Locations
  • Molecular Therapy (publishedVersion, cc-by-nc-nd)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Utrecht University Repository (Utrecht University) (submittedVersion, other-oa)
  • Utrecht University Repository (Utrecht University) (submittedVersion)
Funders
  • ZonMw (43400003, 917.11.337)
  • KWF Kankerbestrijding (UU 2010-4669, UU 2013-6426, UU 2014-6790, UU 2015-7601, UU 2018-11393)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Virus-based gene therapy research
  • Health Sciences › Medicine › Oncology › CAR-T cell therapy research
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › CRISPR and Genetic Engineering
Keywords
vector copy number, CAR T-cell therapy, single nucleotide variants, malignant transformation risk, environmental risk assessment
MeSH terms
Genetic Engineering, Genetic Vectors, Humans, Mutation, Phenotype, Receptors, Antigen, T-Cell, T-Lymphocytes, Genetic Therapy, Immunotherapy, Adoptive, Mutagenesis, Insertional, Virus Integration, Transgenes, Untranslated Regions

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