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Cited by 16CAR-T cell therapy researchImmunotherapy and Immune ResponsesVirus-based gene therapy research

Harmonisation of quality control tests for academic production of CAR-T cells: a position paper from the WP-bioproduction of the UNITC consortium

Open access
Marton, Chrystel, Clémenceau, Béatrice, Dachy, Guillaume, Demerle, Clémence, Derenne, Sophie, Ferrand, Christophe, Giverne, Camille, Latouche, Jean-Baptiste +19 more·2025·Bone Marrow Transplantation
DOI 10.1038/s41409-025-02637-8PMC PMC12401719
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Abstract

This position paper from the Bioproduction Working Group of the UNITC Consortium seeks to harmonize quality control (QC) procedures for academic production of autologous CAR-T cells. The primary objective is to standardize QC testing for batch release in academic cell therapy units. Academic CAR-T manufacturing under the hospital exemption pathway enables faster, more cost-effective production and the use of fresh cells, eliminating the need for cryopreservation. Standardized QC processes are critical to ensure consistent product quality and safety. This paper focuses on key QC measures, including mycoplasma detection using validated commercial kits or in-house methods with on-site validation, endotoxin testing via Limulus Amebocyte Lysate (LAL) or Recombinant Factor C (rFC) assays with validated protocols to prevent matrix interference, vector copy number (VCN) quantification through validated qPCR or ddPCR techniques, and potency assessment through IFN-γ ELISA following antigenic stimulation. Emphasizing method validation and standardized testing, this work underscores the importance of robust QC strategies to ensure the safety and efficacy of CAR-T cell therapies, with ongoing efforts dedicated to optimizing these processes. This workshop focuses on addressing the harmonization of some quality control (QC) measures required for the validation of academic CAR-T cell production :mycoplasma detection; endotoxin testing; vector copy number (VCN) quantification; potency testing and the use of surrogate markers, if applicable. Sterility testing and characterization/identity/purity assessments are not covered in this work.

AI snapshot

Written from the paper’s full text.

TL;DR

This UNITC WP-bioproduction position paper proposes harmonized quality control tests for academic autologous CAR-T cell batch release under hospital exemption, focusing on mycoplasma, endotoxin, vector copy number (VCN), and potency. It recommends validated commercial or in-house nucleic acid tests for mycoplasma, LAL/rFC for endotoxin, qPCR/ddPCR for VCN, and IFN-γ ELISA/ELISpot after antigen-specific stimulation for potency.

Key findings

  • Mycoplasma: the European Pharmacopoeia reference test requires 28 days and ~15 mL, unsuitable for products with 48–72 h shelf life; commercial kits or in-house qPCR/ddPCR are acceptable if locally validated, with sensitivity <10 CFU/mL and validation on CAR-T cell suspension and supernatant.
  • Endotoxin: LAL (gel-clot, chromogenic, turbidimetric) or recombinant Factor C (rFC) assays are recommended; the general injectable limit is 5 EU/kg/hour, and matrix interference from CAR-T proteins/cells must be validated, with results reported in EU/mL and converted to EU/kg.
  • VCN: qPCR and ddPCR are the main methods; qPCR requires standards and is indirect, while ddPCR gives absolute quantification without a standard curve; validation should cover sensitivity, specificity, linearity, and reproducibility, with protocol harmonization and shared reference materials encouraged.
  • Potency: IFN-γ quantification by ELISA or ELISpot after antigen-specific stimulation is chosen; the proposed test includes four conditions—no stimulation, antigen-positive cell line, antigen-negative cell line, and polyclonal stimulation—and ELISA with 18–24 h incubation is likely to be proposed, while ELISpot is more complex and costly.

Methods

  • Position paper developed by the UNITC Consortium WP3-Bioproduction using the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC) methodology recommended by EBMT, based on GMP, European Pharmacopoeia, EMA, ICH, FDA guidance, literature review, a national survey, and expert discussions.
  • The work followed an initial workshop on release requirements for fresh autologous CAR-T products, then used teleconferences, subgroup literature reviews, and a two-day in-person meeting in Lille, France, in October 2024 to draft the document.

Limitations

  • Stated: sterility testing and characterization/identity/purity assessments are not covered and will be addressed in another workshop; potency recommendations are preliminary, with a first comparative ELISA versus ELISpot study to be conducted before final recommendations.
  • Stated/evident: QC methods face matrix interference, limited autologous material, and the need for local validation and standardization; as a position paper, it reports expert consensus and recommendations rather than primary experimental data.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41409-025-02637-8

Cites

40 of 40 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

19 of 28 cited sources checked · 5 supported · 0 flagged · accuracy not yet measured

  • Premisecitation

    Homogenous results were shown in the manufacturing of CD20 CAR T cells freshly used in a clinical phase I melanoma trial produced at two different manufacturing sites.

    “In addition, we could show homogenous results in the manufacturing of CD20 CAR T cells freshly used in a clinical phase I melanoma trial produced at two different manufacturing sides [5].”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [5] Aleksandrova K, Leise J, Priesner C, Aktas M, Apel M, Assenmacher M, et al. Automated manufacturing and characterization of clinical grade autologous CD20 CAR T cells for the treatment of patients with stage III/IV melanoma. Front Immunol. 2024;15:1328368. https://doi.org/10.3389/fimmu.2024.1328368. source
  • Premisecitation

    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].”
    Quote in the paperSubstantial claim4 of 4 sources checked
    • cites [27] Rodriguez-Marquez P, Calleja-Cervantes ME, Serrano G, Oliver-Caldes A, Palacios-Berraquero ML, Martin-Mallo A, et al. CAR density influences antitumoral efficacy of BCMA CAR T cells and correlates with clinical outcome. Sci Adv. 2022;8:eabo0514 https://doi.org/10.1126/sciadv.abo0514. source

      The Results section (page unavailable) reports fewer vector integrations and lower CAR expression in CARLow cells, alongside lower in vitro cytotoxic activity than CARHigh cells. It does not report absent CAR expression from insufficient copies or establish that low copy number compromises clinical product efficacy; its clinical findings instead associate more CARHigh cells with poorer responses. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [28] Baras A, Bocket L, Beauvais D, Hallaert C, Varlet P, Yakoub-Agha I, et al. A real-time quantitative PCR targeting the viral vector for the monitoring of patients treated with axicabtagene ciloleucel. J Mol Diagn. 2021;23:447–54. https://doi.org/10.1016/j.jmoldx.2020.12.004. source

      The Introduction and Discussion (page unavailable) describe vector-copy quantification as a way to monitor CAR T cells and report that their persistence is a marker of long-term clinical efficacy. They do not establish that an insufficient number of vector copies causes low or absent CAR receptor expression, or that this mechanism compromises product efficacy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [29] Luostarinen A, Kailaanmaki A, Turkki V, Koylijarvi M, Kayhty P, Leinonen H, et al. Optimizing lentiviral vector formulation conditions for efficient ex vivo transduction of primary human T cells in chimeric antigen receptor T-cell manufacturing. Cytotherapy. 2024;26:1084–94. https://doi.org/10.1016/j.jcyt.2024.04.002. source

      The Introduction (page unavailable) states that suboptimal multiplicity of infection leads to low CAR expression and impaired anticancer function, supporting the claimed concern about efficacy. It does not establish that a low vector copy number specifically causes this outcome, or explicitly describe absent CAR expression. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [30] Straetemans T, Janssen A, Jansen K, Doorn R, Aarts T, van Muyden ADD, et al. TEG001 insert integrity from vector producer cells until medicinal product. Mol Ther. 2020;28:561–71. https://doi.org/10.1016/j.ymthe.2019.11.030. source

      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)

      Experimental — accuracy not yet measured
  • Premisecitation

    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.”
    Quote in the paperSubstantial claim4 of 4 sources checked
    • cites [28] Baras A, Bocket L, Beauvais D, Hallaert C, Varlet P, Yakoub-Agha I, et al. A real-time quantitative PCR targeting the viral vector for the monitoring of patients treated with axicabtagene ciloleucel. J Mol Diagn. 2021;23:447–54. https://doi.org/10.1016/j.jmoldx.2020.12.004. source

      The Introduction (page unavailable) says monitoring CAR T-cell kinetics could help assess associations with adverse events, and the Discussion (page unavailable) describes measuring axi-cel vector copies. Neither passage, nor the additional passages searched for overexpression and toxicity, says that excessive vector copies cause CAR overexpression or increase toxicity risk. (LLM, conf=0.76)

      Experimental — accuracy not yet measured
    • cites [29] Luostarinen A, Kailaanmaki A, Turkki V, Koylijarvi M, Kayhty P, Leinonen H, et al. Optimizing lentiviral vector formulation conditions for efficient ex vivo transduction of primary human T cells in chimeric antigen receptor T-cell manufacturing. Cytotherapy. 2024;26:1084–94. https://doi.org/10.1016/j.jcyt.2024.04.002. source

      The Introduction (page not provided) says excessive virus may increase vector copy number, a potential risk factor for insertional mutagenesis. It separately says high cell-surface receptor density may increase tonic signaling and accelerate exhaustion, but does not establish that excessive vector copies cause CAR overexpression or that this is the route to increased toxicity risk. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
    • cites [30] Straetemans T, Janssen A, Jansen K, Doorn R, Aarts T, van Muyden ADD, et al. TEG001 insert integrity from vector producer cells until medicinal product. Mol Ther. 2020;28:561–71. https://doi.org/10.1016/j.ymthe.2019.11.030. source

      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
    • cites [31] Kunz A, Gern U, Schmitt A, Neuber B, Wang L, Huckelhoven-Krauss A, et al. Optimized assessment of qPCR-based vector copy numbers as a safety parameter for GMP-grade CAR T cells and monitoring of frequency in patients. Mol Ther Methods Clin Dev. 2020;17:448–54. https://doi.org/10.1016/j.omtm.2020.02.003. source

      The Introduction (page not provided) says vector copy numbers must be assessed before CAR T-cell administration to warrant safety, and the Discussion (page not provided) calls their evaluation mandatory biosafety testing. Neither passage says excessive copies cause CAR overexpression or increase toxicity, so the proposed mechanism is unsupported. (LLM, conf=0.83)

      Experimental — accuracy not yet measured
  • Premisecitation

    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].”
    Quote in the paperSubstantial claim4 of 4 sources checked
    • cites [28] Baras A, Bocket L, Beauvais D, Hallaert C, Varlet P, Yakoub-Agha I, et al. A real-time quantitative PCR targeting the viral vector for the monitoring of patients treated with axicabtagene ciloleucel. J Mol Diagn. 2021;23:447–54. https://doi.org/10.1016/j.jmoldx.2020.12.004. source

      The Introduction describes an integrated CAR transgene, and the Discussion describes measuring axi-cel vector copy numbers, but neither connects a high copy number to insertional mutagenesis. Searches for insertional mutagenesis, oncogene activation, tumor-suppressor disruption, and integration-related risk found no passage addressing that claim. Page numbers were unavailable in our copy. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [29] Luostarinen A, Kailaanmaki A, Turkki V, Koylijarvi M, Kayhty P, Leinonen H, et al. Optimizing lentiviral vector formulation conditions for efficient ex vivo transduction of primary human T cells in chimeric antigen receptor T-cell manufacturing. Cytotherapy. 2024;26:1084–94. https://doi.org/10.1016/j.jcyt.2024.04.002. source

      The Introduction (page not provided) calls increased vector copy number in the host-cell genome a potential risk factor for insertional mutagenesis. It does not describe integration near proto-oncogenes or tumor-suppressor genes, so the specific mechanism in the claim is not supported by this paper. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [30] Straetemans T, Janssen A, Jansen K, Doorn R, Aarts T, van Muyden ADD, et al. TEG001 insert integrity from vector producer cells until medicinal product. Mol Ther. 2020;28:561–71. https://doi.org/10.1016/j.ymthe.2019.11.030. source

      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
    • cites [31] Kunz A, Gern U, Schmitt A, Neuber B, Wang L, Huckelhoven-Krauss A, et al. Optimized assessment of qPCR-based vector copy numbers as a safety parameter for GMP-grade CAR T cells and monitoring of frequency in patients. Mol Ther Methods Clin Dev. 2020;17:448–54. https://doi.org/10.1016/j.omtm.2020.02.003. source

      The Discussion states that viral vectors integrate into the target-cell genome and that assessing integrated vector copy numbers is mandatory for biosafety. The Introduction also describes copy-number assessment as a safety measure. Neither passage says that a high copy number increases insertional-mutagenesis risk or describes activation of proto-oncogenes or disabling of tumor-suppressor genes. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
  • Premisecitation

    Higher degrees of expansion (Cmax) and/or longer durations of expansion (AUC) of CAR-T cells in patients are biomarkers associated with positive clinical responses.

    “Higher degrees of expansion (Cmax) and/or longer durations of expansion (area under the curve, AUC) of CAR-T cells in patients have been identified as biomarkers associated with positive clinical responses [34, 35].”
    • Also stated in: § Potency test methods for assessing the functional activity of CAR-T cells · plain
      “higher expansion levels (Cmax) and/or longer expansion durations (area under the curve, AUC) in patients are biomarkers associated with improved clinical responses [38].”
    Quote in the paperNot a substantial claim2 of 3 sources checked
    • cites [34] Deng Q, Han G, Puebla-Osorio N, Ma MCJ, Strati P, Chasen B, et al. Characteristics of anti-CD19 CAR T cell infusion products associated with efficacy and toxicity in patients with large B cell lymphomas. Nat Med. 2020;26:1878–87. https://doi.org/10.1038/s41591-020-1061-7. source

      In Results, under “A CD8 T-cell exhaustion signature associated with failure to achieve an early molecular response” (page unavailable), patients with a poor early molecular response showed a trend toward reduced CAR T-cell expansion, and early molecular response was associated with later complete response. The paper does not establish peak expansion (Cmax) or expansion over time (AUC) as biomarkers of positive clinical response; its measured response biomarker was tumor-derived cell-free DNA. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [35] Fraietta JA, Lacey SF, Orlando EJ, Pruteanu-Malinici I, Gohil M, Lundh S, et al. Determinants of response and resistance to CD19 chimeric antigen receptor (CAR) T cell therapy of chronic lymphocytic leukemia. Nat Med. 2018;24:563–71. https://doi.org/10.1038/s41591-018-0010-1. source
    • cites [38] Halford Z, Anderson MK, Bennett LL. Axicabtagene ciloleucel: clinical data for the use of CAR T-cell therapy in relapsed and refractory large B-cell lymphoma. Ann Pharmacother. 2021;55:390–405. https://doi.org/10.1177/1060028020944233. source
  • Classified as probably not a substantial claim. 20
  • May combine two claims. 18

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    The LAL chromogenic method is more sensitive than the gel-clot method and allows for more precise quantification.

    “The chromogenic method is more sensitive than the gel-clot method and allows for more precise quantification.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationreasoning

    Thorough validation of VCN quantification methods helps minimize batch-to-batch variations and ensures result consistency.

    “A thorough validation process helps minimize batch-to-batch variations and ensures result consistency.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Harmonizing VCN quantification protocols can be challenging because reagents must be adapted to the vector used for each genetic modification, which is easier with backbone-specific probes.

    “However, harmonization can be challenging, as reagents must be adapted to the vector used for each genetic modification (which is easier with backbone-specific probes).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Scaling on-site cell manufacturing across numerous medical centers while ensuring consistent product quality remains a major challenge.

    “However, scaling this practice across numerous medical centers while ensuring consistent product quality remains a major challenge.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationnone given

    Different laboratories or production centers may use different reagents, equipment, and protocols, which can lead to variations in VCN quantification results.

    “Each laboratory or production center may use different reagents, equipment, and protocols, potentially leading to variations in results.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    Given the use of GMP-certified reagents and a controlled, semi-closed environment, the risk of mycoplasma contamination is considered reduced.

    “Given the use of GMP-certified reagents for CAR-T cell production process, as well as a controlled, semi-closed environment, the risk of mycoplasma contamination is considered reduced.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    ddPCR is expensive and requires specialized equipment, and may be slower than qPCR in some laboratories.

    “Expensive method requiring specialized equipment. May be slower than qPCR in some laboratories.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    The LAL turbidimetric method is faster, making it useful for high-throughput testing.

    “The turbidimetric method is faster, making it useful for high-throughput testing.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    CAR-T cell products, particularly autologous ones, are often produced in small quantities, making quality testing challenging as each test requires a certain volume of the final product, potentially reducing the amount available for the patient.

    “Moreover, CAR-T cell products, particularly autologous ones, are often produced in small quantities. This makes quality testing challenging, as each test requires a certain volume of the final product, potentially reducing the amount available for the patient.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    The reference test for mycoplasma detection requires culturing mycoplasmas using a combination of broth culture, solid permissive medium culture, and fluorescent antibody detection of non-cultivable organisms grown on a cell monolayer.

    “This test requires culturing mycoplasmas using a combination of three methods: broth culture, solid permissive medium culture, and fluorescent antibody detection of non-cultivable organisms grown on a cell monolayer.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Chapter 2.6.7 of the European Pharmacopoeia

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Classified as probably not a substantial claim.

    Premisecitation

    In-house developed qPCR or ddPCR methods for mycoplasma detection require full validation by the laboratory in accordance with ICH Q2 guidelines.

    “Full validation to be performed by the laboratory, in accordance with ICH Q2 guidelines.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites ICH Q2

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Cellular components or excipients may interfere with the LAL test by masking the presence of endotoxins or disrupting the lysate-endotoxin reaction.

    “Cellular components or excipients may interfere with the test by masking the presence of endotoxins or disrupting the lysate-endotoxin reaction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisenone given

    ddPCR provides absolute quantification of VCN, eliminating the need for a standard curve, with high precision, sensitivity, and reproducibility, and is less prone to variations than qPCR.

    “ddPCR | Absolute quantification of VCN, eliminating the need for a standard curve. High precision, sensitivity, and reproducibility. Less prone to variations than qPCR, allowing detection of copy number variations even in heterogeneous samples.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Commercial kits for mycoplasma detection have a sensitivity of <10 CFU/mL as stated by the supplier.

    “<10 CFU/mL (as stated by the supplier)”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    The Biofire Mycoplasma kit detects more than 120 strains.

    “>120 strains”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Variability in vector copy number among modified cells in CAR-T products can complicate VCN quantification and lead to significant result fluctuations.

    “This variability can complicate quantification and lead to significant result fluctuations.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: CAR-T products often consist of heterogeneous cell populations, with modified cells containing varying amounts of vector copies.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    Academic production of CAR-T cells offers a significant advantage in VCN quantification, as the same method can be applied both to the production process and patient monitoring.

    “Of note, academic production of CAR-T cells offers a significant advantage in VCN quantification, as the same method can be applied both to the production process and patient monitoring.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Academic production of autologous CAR-T cells enables the use of fresh cell products, avoiding the cryopreservation/thawing step, which poses a risk of quantitative and qualitative loss of CAR-T cells.

    “Academic CAR-T manufacturing under the hospital exemption pathway enables faster, more cost-effective production and the use of fresh cells, eliminating the need for cryopreservation.”
    • Also stated in: § Introduction and state of the art · plain
      “Additionally, local academic production enables the administration of fresh cell products, avoiding the cryopreservation/thawing step, which poses a risk of quantitative and qualitative loss of CAR-T cells.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    In a Phase 1 dose escalation and expansion trial using fresh bispecific anti-CD20/anti-CD19 CAR T cells for relapsed B-cell malignancies, on-site manufacturing and infusion of non-cryopreserved CAR T cells were feasible and therapeutically safe, with low toxicity and high efficacy.

    “In a Phase 1 dose escalation and expansion trial using fresh bispecific anti-CD20/anti-CD19 CAR T cells for relapsed B-cell malignancies, investigators found that on-site manufacturing and infusion of non-cryopreserved CAR T cells were both feasible and therapeutically safe, demonstrating low toxicity and high efficacy [4].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [4] Shah NN, Johnson BD, Schneider D, Zhu F, Szabo A, Keever-Taylor CA, et al. Bispecific anti-CD20, anti-CD19 CAR T cells for relapsed B cell malignancies: a phase 1 dose escalation and expansion trial. Nat Med. 2020;26:1569–75. https://doi.org/10.1038/s41591-020-1081-3. source

  • Classified as probably not a substantial claim.

    Interpretationnone given

    Quality control remains a significant hurdle due to its complexity, especially concerning potency assessment.

    “While the simplicity of CAR-T cell production using automated bioreactors with closed systems enables broader manufacturing access, quality control remains a significant hurdle due to its complexity, especially concerning potency assessment.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisenone given

    qPCR is an indirect method that requires standards for quantification and can be subject to variations depending on amplification efficiency and biases introduced during analysis.

    “qPCR is an indirect method that requires the use of standards for quantification. It can be subject to variations depending on amplification efficiency and biases introduced during analysis.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Interpretationnone given

    The ELISpot test provides additional quantitative data (number of cells capable of producing IFN-γ) but is more complex and costlier compared to the ELISA technique.

    “While the ELISpot test provides additional quantitative data (number of cells capable of producing IFN-γ), it is more complex and costlier (not universally available in all labs) compared to the ELISA technique.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Interpretationnone given

    The potency test can also be used to validate a freezing/thawing step and to conduct stability studies.

    “This test can also be used to validate a freezing/thawing step and to conduct stability studies.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    The IFN-γ quantification test is only relevant if it specifically quantifies CAR-dependent IFN-γ production.

    “The working group emphasizes that this test is only relevant if it specifically quantifies CAR-dependent IFN-γ production.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Method validation and standardized testing ensure the safety and efficacy of academic CAR-T cell therapies.

    “This work emphasizes method validation and standardized testing to ensure the safety and efficacy of academic CAR-T cell therapies.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Quantitative evaluation of cytotoxic activity, cytokine production, or proliferation helps validate the CAR-T manufacturing process and ensures the quality of the final CAR-T cell preparation.

    “A quantitative evaluation of one of these functional activities helps validate the manufacturing process and ensures the quality of the final CAR-T cell preparation.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    A proliferation assay based on fluorochrome labeling (e.g., CFSE) and flow cytometry analysis requires a minimum of 3 to 4 days of CAR-T cell culture following antigen-specific stimulation, making it incompatible with the release of fresh CAR-T products.

    “it requires a minimum of 3 to 4 days of CAR-T cell culture following antigen-specific stimulation. This extended timeframe is incompatible with the release of fresh CAR-T products.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationnone given

    CAR-T cells with insufficient potency may be ineffective, while an overly potent product can cause toxicity, including cytokine release syndrome (CRS), neurological (ICANS), and hematological (ICAHT) toxicities.

    “CAR-T cells with insufficient potency may be ineffective, whereas an overly potent product can lead to toxicity, such as cytokine release syndrome (CRS) or on-target, off-tumor toxicity, including neurological (ICANS) and hematological (ICAHT) toxicities.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Obtaining additional patient-derived T lymphocytes is incompatible with clinical-scale CAR-T cell production.

    “Since obtaining additional patient-derived T lymphocytes is incompatible with clinical-scale CAR-T cell production”
    Quote in the paperNot a substantial claim
29 of 29

  • The paper relies on this without support.

    Academic production of autologous CAR-T cells is faster and more cost-effective than commercial production.

    “Academic CAR-T manufacturing under the hospital exemption pathway enables faster, more cost-effective production”
    “Academic production of autologous CAR-T cells offers several potential advantages, such as faster and more cost-effective production”

  • The paper relies on this without support.

    For injectable products, the endotoxin limit is 5 EU/kg/hour.

    “Generally, for injectable products, the limit is 5 EU/kg/hour (endotoxin units per kilogram of body weight per hour).”

  • The paper relies on this without support.

    CAR-T products often consist of heterogeneous cell populations, with modified cells containing varying amounts of vector copies.

    “CAR-T products often consist of heterogeneous cell populations, with modified cells containing varying amounts of vector copies.”

  • The paper relies on this without support.

    VCN quantification varies depending on the vector used in the production process.

    “Additionally, VCN quantification varies depending on the vector used in the production process.”

  • The paper relies on this without support.

    Currently, the most performed potency test is the quantification of interferon-gamma (IFN-γ) production after CAR-T cell stimulation.

    “Currently, the most performed potency test is the quantification of interferon-gamma (IFN-γ) production after CAR-T cell stimulation.”

  • The paper relies on this without support.

    Currently, commercially available CAR-T cell products with MA are released based on IFN-γ quantification.

    “Currently, commercially available CAR-T cell products with MA are released based on IFN-γ quantification.”

  • The paper relies on this without support.

    Most batches will be released fresh.

    “since most batches will be released fresh”

  • The paper relies on this without support.

    All currently approved commercial CAR-T products are released based on IFN-γ quantification.

    “all currently approved commercial CAR-T products are released based on IFN-γ quantification.”
8 of 8

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Five cytotoxicity techniques are called four

    Minor

    The text says there are four techniques for measuring target-cell lysis but lists five.

  • ELISpot is called costlier despite lower listed costs

    Minor

    The text calls ELISpot costlier than ELISA, whereas Table 5 lists a lower per-test strip cost for ELISpot (€50 versus €60) and a lower upper end for pre-coated plates (€400 versus €800).

  • The three listed effector-to-target ratios include a duplicate

    Minor

    The table calls for at least three ratios, but 0.1/1 and 1/10 are the same ratio, leaving only two distinct ratios in the list.

3 of 3

Cites

Flagged first, then by citations

Cited by

Sorted by citations

Related

Authors
Marton, C., Clémenceau, B., Dachy, G., Demerle, C., Derenne, S., Ferrand, C., Giverne, C., Latouche, J.-B., Lemée, L., Martinet, J., Bonig, H., Bensoussan, D., Chabannon, C., Köhl, U., Deschamps, M., De Vos, J., Diana, J.-S., Dougé, A., Forcade, E., Galaine, J., Thiant, S., Galy, A., Larghero, J., Reppel, L., Viel, S., Boyer, O., & Yakoub-Agha, I.
Affiliations
  • Inserm (FR)
  • Cliniques Universitaires Saint-Luc (BE)
  • Établissement Français du Sang (FR)
  • Goethe University Frankfurt (DE)
  • Centre Hospitalier Régional et Universitaire de Nancy (FR)
  • Hôpital Necker-Enfants Malades (FR)
  • Université Clermont Auvergne (FR)
  • Hôpital Maisonneuve-Rosemont (CA)
  • Hospices Civils de Lyon (FR)
Corresponding author
Marton, Chrystel
ORCID
Venue
Bone Marrow Transplantation
Publisher
Springer Science and Business Media LLC
Published
2025-05-29
Volume
60
Issue
9
Pages
1209-1217
ISSN
  • 0268-3369 (ISSN-L)
  • 1476-5365
DOI
10.1038/s41409-025-02637-8
PMC
PMC12401719
OpenAlex
W4410864172
Cited by
16
References
40
Citations by year
2026: 15 · 2025: 1
FWCI
6.66
Type
journal article
Language
en
Update notices
correction (2025-06-30)
Open access
Licence
Locations
  • Bone Marrow Transplantation (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by)
  • HAL (submittedVersion, cc-by)
  • Europe PMC (PubMed Central) (submittedVersion, cc-by)
  • Digital Access to Libraries (Université catholique de Louvain (UCL), l'Université de Namur (UNamur) and the Université Saint-Louis (USL-B)) (submittedVersion)
  • LillOA (Université de Lille (University Of Lille)) (submittedVersion)
  • Fraunhofer-Publica (Fraunhofer-Gesellschaft) (submittedVersion)
Funders
Centre hospitalier régional universitaire de Lille
Topics
  • Health Sciences › Medicine › Oncology › CAR-T cell therapy research
  • Life Sciences › Immunology and Microbiology › Immunology › Immunotherapy and Immune Responses
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Virus-based gene therapy research
Keywords
CAR T cell manufacturing, quality control, harmonization, batch release, mycoplasma detection, endotoxin testing, Limulus amebocyte lysate assay, potency assay, method validation
MeSH terms
Receptors, Chimeric Antigen, Endotoxins, Humans, Quality Control, T-Lymphocytes, Immunotherapy, Adoptive

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-28.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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