{
  "abstract": "Background CD19-directed chimeric antigen receptor (CAR) T-cell therapies have transformed the treatment landscape for pediatric B-cell acute lymphoblastic leukemia (B-ALL), yet relapses driven by antigen escape remain a major limitation. Dual-targeting CAR approaches recognizing CD19 and CD22 have shown promising clinical activity, but sustained remissions are limited by insufficient CAR T-cell persistence.Methods CAR22.19, a fully human tandem CD19/CD22 CAR, was developed and administered under a named-patient program to nine heavily pretreated pediatric patients with relapsed or refractory B-ALL. Treatment indications were CD19-negative blast population (n=5), relapse after CD19 CAR T (n=3) and/or restricted access to approved CAR T-cell products (n=3). Autologous and donor-derived CAR22.19 T-cells (CART22.19) were manufactured using a good manufacturing practice-compliant, semiautomated fresh-in-fresh-out process. Safety and efficacy were assessed through standardized clinical monitoring, measurable residual disease analysis, and CAR T-cell kinetics.Results Preclinical validation demonstrated antigen-specific cytotoxicity and dual antigen activity. Clinically, CART22.19 were well tolerated, with no treatment-related deaths and no grade ≥3 neurotoxicity, while grade ≥3 cytokine release syndrome occurred in 38.5% (5/13) of infusions and resolved with standard interventions. An initial complete molecular remission was achieved in 78% (7/9) of patients, with a 12-month overall survival rate of 55.6% (95% CI, 20.4-80.5%). Complete remission in CD19⁻CD22⁺ disease underscores the functional contribution of the CD22-targeting domain, whereas all patients refractory to prior CD19 CAR T-cell therapy relapsed early despite retained CD19⁺CD22⁺ expression. Limited in vivo persistence may represent a contributing factor to treament failure. Notably, durable remission and sustained functional persistence of CART22.19 was achieved in one patient refractory to autologous CART22.19 following infusion of donor-derived CART22.19 after reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (alloHSCT) in nonremission.Conclusions CART22.19 therapy demonstrated a favorable safety profile and promising clinical activity in a high-risk pediatric population, with dual targeting enabling disease control in CD19-negative leukemia. Nonetheless, limited CAR T-cell persistence may represent an important obstacle to sustained remission. Our findings support further clinical development of CART22.19 and indicate that donor-derived CAR T-cells following RIC alloHSCT may represent a potential therapeutic strategy to enhance persistence and improve outcomes in heavily pretreated pediatric patients.",
  "authors": [
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Anna-Sophia Mast"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "Excellence cluster iFIT (EXC 2180) “Image-Guided and Functionally Instructed Tumor Therapies”, University Hospital Tübingen, Tübingen, Germany",
        "German Cancer Research Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center, Heidelberg, Germany"
      ],
      "name": "Peter Lang"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Regensburg, Regensburg, Germany",
        "Leibniz Institute for Immunotherapy, Regensburg, Germany"
      ],
      "name": "Patrick Schlegel"
    },
    {
      "affiliations": [
        "Princess Máxima Center for Pediatric Oncology, Utrecht, Netherlands"
      ],
      "name": "Friso G Calkoen"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Daniel Atar"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "German Cancer Research Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center, Heidelberg, Germany",
        "Department of Pediatric Hematology, Oncology and Stem Cell Transplantation, University of Regensburg, Regensburg, Germany",
        "Hopp-Children’s Cancer Center Heidelberg (KiTZ), Heidelberg, Germany",
        "B310 Clinical Cooperation Unit Pediatric Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany",
        "Department of Pediatric Oncology, Hematology, and Immunology, Heidelberg University Hospital, Heidelberg, Germany"
      ],
      "name": "Sophia Scheuermann"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Sylvia Klein"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Christiane Braun"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Florian Schinle"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Marina Schmidt"
    },
    {
      "affiliations": [
        "Department of Hematology and Oncology, University Hospital Tübingen, Tübingen, Baden-Württemberg, Germany"
      ],
      "name": "Luca Hensen"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "German Cancer Research Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center, Heidelberg, Germany"
      ],
      "name": "Martin Ebinger"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Michaela Döring"
    },
    {
      "affiliations": [
        "Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Jürgen F Schäfer"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany"
      ],
      "name": "Johannes Schulte"
    },
    {
      "affiliations": [
        "Department of Hematology and Oncology, University Hospital Tübingen, Tübingen, Baden-Württemberg, Germany"
      ],
      "name": "Wolfgang A Bethge"
    },
    {
      "affiliations": [
        "German Cancer Research Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center, Heidelberg, Germany",
        "Department of Hematology and Oncology, University Hospital Tübingen, Tübingen, Baden-Württemberg, Germany"
      ],
      "name": "Claudia Lengerke"
    },
    {
      "affiliations": [
        "King Abdullah International Medical Research Center, Riyadh, Riyadh Province, Saudi Arabia",
        "Department of Oncology, Ministry of National Guard Health Affairs, Riyadh, Riyadh Province, Saudi Arabia"
      ],
      "name": "Bader Alahmari"
    },
    {
      "affiliations": [
        "Lentigen Technology, Gaithersburg, Maryland, USA"
      ],
      "name": "Peirong Hu"
    },
    {
      "affiliations": [
        "Lentigen Technology, Gaithersburg, Maryland, USA"
      ],
      "name": "Dina Schneider"
    },
    {
      "affiliations": [
        "Lentigen Technology, Gaithersburg, Maryland, USA"
      ],
      "name": "Rimas J Orentas"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "Research and Development Immunotherapy, Miltenyi Biotec BV & Co KG, Bergisch Gladbach, Germany"
      ],
      "name": "Rupert Handgretinger"
    },
    {
      "affiliations": [
        "Department of General Pediatrics, Hematology and Oncology, University Hospital Tübingen, Tübingen, Germany",
        "Excellence cluster iFIT (EXC 2180) “Image-Guided and Functionally Instructed Tumor Therapies”, University Hospital Tübingen, Tübingen, Germany",
        "German Cancer Research Consortium (DKTK), Partner Site Tübingen, German Cancer Research Center, Heidelberg, Germany",
        "Hopp-Children’s Cancer Center Heidelberg (KiTZ), Heidelberg, Germany",
        "B310 Clinical Cooperation Unit Pediatric Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany",
        "Department of Pediatric Oncology, Hematology, and Immunology, Heidelberg University Hospital, Heidelberg, Germany"
      ],
      "name": "Christian Martin Seitz"
    }
  ],
  "title": "Human CART22.19 therapy in refractory pediatric B-ALL: insights from a named-patient cohort",
  "uid": "265d52fa-6b17-5908-beff-6d7976f74df5"
}