{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T19:52:50Z","timestamp":1791229970800,"version":"4.1.0"},"reference-count":43,"publisher":"Oxford University Press (OUP)","issue":"10","license":[{"start":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T00:00:00Z","timestamp":1789516800000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Sonoma Biotherapeutics"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Chimeric antigen receptor (CAR)-regulatory T cell (Treg) therapies represent a promising approach for autoimmune diseases, but their nonclinical safety assessment remains challenging due to antigen-, disease-, and species-specific pharmacology that limits the relevance of conventional animal models. SBT777101, a CAR-Treg therapy targeting citrullinated proteins associated with rheumatoid arthritis and hidradenitis suppurativa, was evaluated using a nonclinical strategy centered on in vitro and ex vivo New Approach Methodologies (NAMs) and in vivo studies benchmarked against untransduced polyclonal Tregs,\u00a0which are manufactured identically but lack the CAR and have an established clinical safety record, complemented by immunodeficient mouse studies. We hypothesized that CAR engineering would not destabilize the Treg phenotype or introduce new toxicological liabilities relative to polyclonal Tregs. SBT777101 maintained phenotypic stability under repeated stimulation and proinflammatory conditions, produced minimal proinflammatory cytokines following activation, and demonstrated immunomodulatory activity comparable to untransduced Tregs. Tissue cross-reactivity and primary cell studies identified limited membrane-associated binding, no evidence of CAR-mediated cytotoxicity or activation in normal human tissues, and no off-target binding by broad protein array screening. Immunosuppressive activity toward natural killer and CD8+ T cell responses was limited and comparable to polyclonal Tregs. Lentiviral integration site analyses demonstrated polyclonal integration profiles without evidence of transformation or abnormal growth in a cytokine- and activation-independent growth assay. This study establishes a combined\u00a0in vivo and NAM-based nonclinical safety framework for CAR-Treg therapies and demonstrates that CAR engineering of SBT777101 does not introduce new safety liabilities relative to unmodified polyclonal Tregs. These findings supported progression of SBT777101 into Phase 1 clinical trials and offer a generalizable approach for evaluating the safety of future CAR-Treg therapeutics.<\/jats:p>","DOI":"10.1093\/toxsci\/kfag125","type":"journal-article","created":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T11:58:44Z","timestamp":1789473524000},"source":"Crossref","is-referenced-by-count":0,"title":["Nonclinical safety assessment of SBT777101, a CAR-engineered regulatory T cell therapy for autoimmune diseases"],"prefix":"10.1093","volume":"209","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-5702-4164","authenticated-orcid":false,"given":"Herve","family":"Lebrec","sequence":"first","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4729-0247","authenticated-orcid":false,"given":"Jonathan M","family":"Clingan","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anne-Renee","family":"van der Vuurst de Vries","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lauren","family":"Mihalcik","sequence":"additional","affiliation":[{"name":"Aclairo Pharmaceutical Development Group , Vienna, VA 22182,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuchi","family":"Honaker","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sara","family":"Charmsaz","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seonhwa","family":"Dura","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kathryn A","family":"Hooper","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuanyuan","family":"Xiao","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michelle","family":"Blake","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Max","family":"Fiebiger","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Radha","family":"Dhayal","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christine","family":"Saechao","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexandre","family":"Iannello","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fred","family":"Ramsdell","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jeffrey A","family":"Bluestone","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , South San Francisco, CA 94080,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Josh","family":"Beilke","sequence":"additional","affiliation":[{"name":"Sonoma Biotherapeutics , Seattle, WA 98119,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,9,15]]},"reference":[{"key":"2026100515071248000_kfag125-B1","doi-asserted-by":"publisher","first-page":"1078","DOI":"10.1016\/j.cell.2015.08.021","article-title":"A distinct function of regulatory T cells in tissue protection","volume":"162","author":"Arpaia","year":"2015","journal-title":"Cell"},{"key":"2026100515071248000_kfag125-B2","doi-asserted-by":"publisher","first-page":"949","DOI":"10.1016\/j.immuni.2013.10.016","article-title":"Self-antigen-driven activation induces instability of regulatory T cells during an inflammatory autoimmune response","volume":"39","author":"Bailey-Bucktrout","year":"2013","journal-title":"Immunity"},{"key":"2026100515071248000_kfag125-B3","doi-asserted-by":"publisher","first-page":"431","DOI":"10.1016\/j.jbspin.2012.01.008","article-title":"Citrullination under physiological and pathological conditions","volume":"79","author":"Baka","year":"2012","journal-title":"Joint Bone Spine"},{"key":"2026100515071248000_kfag125-B4","doi-asserted-by":"publisher","first-page":"1156","DOI":"10.1056\/NEJMra1911109","article-title":"Tolerance in the age of immunotherapy","volume":"383","author":"Bluestone","year":"2020","journal-title":"N Engl J Med"},{"key":"2026100515071248000_kfag125-B5","doi-asserted-by":"publisher","first-page":"315ra189","DOI":"10.1126\/scitranslmed.aad4134","article-title":"Type 1 diabetes immunotherapy using polyclonal regulatory T cells","volume":"7","author":"Bluestone","year":"2015","journal-title":"Sci Transl Med"},{"key":"2026100515071248000_kfag125-B6","doi-asserted-by":"publisher","first-page":"154","DOI":"10.1126\/science.aau2688","article-title":"T(reg) cells-the next frontier of cell therapy","volume":"362","author":"Bluestone","year":"2018","journal-title":"Science"},{"key":"2026100515071248000_kfag125-B7","doi-asserted-by":"publisher","DOI":"10.1126\/scitranslmed.aav5908","article-title":"Neutrophil extracellular traps, B cells, and type I interferons contribute to immune dysregulation in hidradenitis suppurativa","author":"Byrd","year":"2019","journal-title":"Sci Transl Med"},{"key":"2026100515071248000_kfag125-B8","doi-asserted-by":"publisher","first-page":"2507","DOI":"10.4049\/jimmunol.1500801","article-title":"Control of regulatory T cell migration, function, and homeostasis","volume":"195","author":"Campbell","year":"2015","journal-title":"J Immunol"},{"key":"2026100515071248000_kfag125-B9","doi-asserted-by":"publisher","first-page":"431","DOI":"10.1002\/art.40737","article-title":"Adoptive Treg cell therapy in a patient with systemic lupus erythematosus","volume":"71","author":"Dall\u2019Era","year":"2019","journal-title":"Arthritis Rheumatol"},{"key":"2026100515071248000_kfag125-B10","doi-asserted-by":"publisher","first-page":"72","DOI":"10.1097\/BOR.0000000000000452","article-title":"Rheumatoid arthritis and citrullination","volume":"30","author":"Darrah","year":"2018","journal-title":"Curr Opin Rheumatol"},{"key":"2026100515071248000_kfag125-B11","doi-asserted-by":"publisher","first-page":"1207","DOI":"10.1053\/j.gastro.2012.07.116","article-title":"Safety and efficacy of antigen-specific regulatory T-cell therapy for patients with refractory Crohn\u2019s disease","volume":"143","author":"Desreumaux","year":"2012","journal-title":"Gastroenterology"},{"key":"2026100515071248000_kfag125-B12","doi-asserted-by":"publisher","first-page":"252","DOI":"10.3389\/fimmu.2018.00252","article-title":"Clinical grade regulatory CD4(+) T cells (Tregs): moving toward cellular-based immunomodulatory therapies","volume":"9","author":"Duggleby","year":"2018","journal-title":"Front Immunol"},{"key":"2026100515071248000_kfag125-B13","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1097\/BOR.0000000000000356","article-title":"Anticitrullinated protein antibodies: origin and role in the pathogenesis of rheumatoid arthritis","volume":"29","author":"England","year":"2017","journal-title":"Curr Opin Rheumatol"},{"key":"2026100515071248000_kfag125-B14","doi-asserted-by":"publisher","first-page":"e123","DOI":"10.1016\/j.bbmt.2018.12.756","article-title":"Cytokine release syndrome with chimeric antigen receptor T cell therapy","volume":"25","author":"Frey","year":"2019","journal-title":"Biol Blood Marrow Transplant"},{"key":"2026100515071248000_kfag125-B15","doi-asserted-by":"publisher","first-page":"R182","DOI":"10.1186\/ar4372","article-title":"Differences in synovial fluid cytokine levels but not in synovial tissue cell infiltrate between anti-citrullinated peptide\/protein antibody-positive and -negative rheumatoid arthritis patients","volume":"15","author":"Gomez-Puerta","year":"2013","journal-title":"Arthritis Res Ther"},{"key":"2026100515071248000_kfag125-B16","doi-asserted-by":"publisher","first-page":"1860","DOI":"10.1038\/s41591-022-01960-7","article-title":"Post-infusion CAR T(reg) cells identify patients resistant to CD19-CAR therapy","volume":"28","author":"Good","year":"2022","journal-title":"Nat Med"},{"key":"2026100515071248000_kfag125-B17","first-page":"1","article-title":"Tissue cross-reactivity studies for monoclonal antibodies: predictive value and use for selection of relevant animal species for toxicity testing","author":"Hall","year":"2010","journal-title":"Pharm Sci Encyclopedia"},{"key":"2026100515071248000_kfag125-B18","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1016\/j.ceb.2015.02.004","article-title":"Glial fibrillary acidic protein (GFAP) and the astrocyte intermediate filament system in diseases of the central nervous system","volume":"32","author":"Hol","year":"2015","journal-title":"Curr Opin Cell Biol"},{"key":"2026100515071248000_kfag125-B19","doi-asserted-by":"publisher","first-page":"700879","DOI":"10.3389\/fcell.2021.700879","article-title":"Synovial fluid of patient with rheumatoid arthritis enhanced osmotic sensitivity through the cytotoxic edema module in synoviocytes","volume":"9","author":"Ji","year":"2021","journal-title":"Front Cell Dev Biol"},{"key":"2026100515071248000_kfag125-B20","doi-asserted-by":"publisher","first-page":"465","DOI":"10.3904\/kjim.2018.364","article-title":"Effect of biologics in the level of cytokines in the synovial fluid of patients with ankylosing spondylitis","volume":"35","author":"Koo","year":"2020","journal-title":"Korean J Intern Med"},{"key":"2026100515071248000_kfag125-B21","doi-asserted-by":"publisher","first-page":"1138","DOI":"10.1177\/0192623310382559","article-title":"Use of tissue cross-reactivity studies in the development of antibody-based biopharmaceuticals: history, experience, methodology, and future directions","volume":"38","author":"Leach","year":"2010","journal-title":"Toxicol Pathol"},{"key":"2026100515071248000_kfag125-B22","doi-asserted-by":"publisher","first-page":"184","DOI":"10.3389\/fphar.2015.00184","article-title":"Regulatory T cell-mediated anti-inflammatory effects promote successful tissue repair in both indirect and direct manners","volume":"6","author":"Lei","year":"2015","journal-title":"Front Pharmacol"},{"key":"2026100515071248000_kfag125-B23","doi-asserted-by":"publisher","first-page":"1295","DOI":"10.1084\/jem.193.11.1295","article-title":"Human CD25(+)CD4(+) T regulatory cells suppress naive and memory T cell proliferation and can be expanded in vitro without loss of function","volume":"193","author":"Levings","year":"2001","journal-title":"J Exp Med"},{"key":"2026100515071248000_kfag125-B24","doi-asserted-by":"publisher","first-page":"1817","DOI":"10.2337\/dc12-0038","article-title":"Administration of CD4\u2009+\u2009CD25highCD127\u2212 regulatory T cells preserves beta-cell function in type 1 diabetes in children","volume":"35","author":"Marek-Trzonkowska","year":"2012","journal-title":"Diabetes Care"},{"key":"2026100515071248000_kfag125-B25","doi-asserted-by":"publisher","first-page":"7428","DOI":"10.1038\/s41598-018-25574-7","article-title":"A phase I clinical trial with ex vivo expanded recipient regulatory T cells in living donor kidney transplants","volume":"8","author":"Mathew","year":"2018","journal-title":"Sci Rep"},{"key":"2026100515071248000_kfag125-B26","doi-asserted-by":"publisher","first-page":"2012","DOI":"10.1182\/blood.2024026446","article-title":"Donor regulatory T-cell therapy to prevent graft-versus-host disease","volume":"145","author":"Meyer","year":"2025","journal-title":"Blood"},{"key":"2026100515071248000_kfag125-B27","doi-asserted-by":"publisher","first-page":"843","DOI":"10.1038\/mt.2010.24","article-title":"Case report of a serious adverse event following the administration of T cells transduced with a chimeric antigen receptor recognizing ERBB2","volume":"18","author":"Morgan","year":"2010","journal-title":"Mol Ther"},{"key":"2026100515071248000_kfag125-B28","doi-asserted-by":"publisher","first-page":"39","DOI":"10.1016\/j.coi.2015.12.009","article-title":"T(reg) stability: to be or not to be","volume":"39","author":"Overacre","year":"2016","journal-title":"Curr Opin Immunol"},{"key":"2026100515071248000_kfag125-B29","doi-asserted-by":"publisher","first-page":"1353","DOI":"10.1038\/ni1536","article-title":"CD4+CD25+FOXP3+ regulatory T cells induce cytokine deprivation-mediated apoptosis of effector CD4+ T cells","volume":"8","author":"Pandiyan","year":"2007","journal-title":"Nat Immunol"},{"key":"2026100515071248000_kfag125-B30","doi-asserted-by":"publisher","first-page":"1797186","DOI":"10.3389\/fimmu.2026.1797186","article-title":"Regulatory T cell therapies: biological foundations, engineering strategies, and clinical translation","volume":"17","author":"Plaisse","year":"2026","journal-title":"Front Immunol"},{"key":"2026100515071248000_kfag125-B31","doi-asserted-by":"publisher","first-page":"158","DOI":"10.1038\/s41577-019-0232-6","article-title":"T(reg) cell-based therapies: challenges and perspectives","volume":"20","author":"Raffin","year":"2020","journal-title":"Nat Rev Immunol"},{"key":"2026100515071248000_kfag125-B32","doi-asserted-by":"publisher","first-page":"546","DOI":"10.1016\/j.immuni.2008.02.017","article-title":"Regulatory T cell-derived interleukin-10 limits inflammation at environmental interfaces","volume":"28","author":"Rubtsov","year":"2008","journal-title":"Immunity"},{"key":"2026100515071248000_kfag125-B33","doi-asserted-by":"publisher","first-page":"1643","DOI":"10.1002\/art.41385","article-title":"Different hierarchies of anti-modified protein autoantibody reactivities in rheumatoid arthritis","volume":"72","author":"Sahlstrom","year":"2020","journal-title":"Arthritis Rheumatol"},{"key":"2026100515071248000_kfag125-B34","doi-asserted-by":"publisher","first-page":"1125","DOI":"10.1111\/ajt.15700","article-title":"Applicability, safety, and biological activity of regulatory T cell therapy in liver transplantation","volume":"20","author":"Sanchez-Fueyo","year":"2020","journal-title":"Am J Transplant"},{"key":"2026100515071248000_kfag125-B35","doi-asserted-by":"publisher","first-page":"1627","DOI":"10.1016\/S0140-6736(20)30167-7","article-title":"Regulatory cell therapy in kidney transplantation (the one study): a harmonised design and analysis of seven non-randomised, single-arm, phase 1\/2a trials","volume":"395","author":"Sawitzki","year":"2020","journal-title":"Lancet"},{"key":"2026100515071248000_kfag125-B36","doi-asserted-by":"publisher","first-page":"2317","DOI":"10.1182\/bloodadvances.2019000219","article-title":"Clonal expansion of CAR T cells harboring lentivector integration in the cbl gene following anti-CD22 CAR T-cell therapy","volume":"3","author":"Shah","year":"2019","journal-title":"Blood Adv"},{"key":"2026100515071248000_kfag125-B37","doi-asserted-by":"publisher","first-page":"104328","DOI":"10.1016\/j.drudis.2025.104328","article-title":"Opportunities and insights from pharmaceutical companies on the current use of new approach methodologies in nonclinical safety assessment","volume":"30","author":"Shenton","year":"2025","journal-title":"Drug Discov Today"},{"key":"2026100515071248000_kfag125-B38","doi-asserted-by":"publisher","first-page":"609","DOI":"10.1007\/s00296-022-05103-6","article-title":"Cytokines and chemokines multiplex analysis in patients with low disease activity rheumatoid arthritis","volume":"42","author":"Skrzypkowska","year":"2022","journal-title":"Rheumatol Int"},{"key":"2026100515071248000_kfag125-B39","doi-asserted-by":"publisher","first-page":"196","DOI":"10.1002\/art.40699","article-title":"Recognition of amino acid motifs, rather than specific proteins, by human plasma cell-derived monoclonal antibodies to posttranslationally modified proteins in rheumatoid arthritis","volume":"71","author":"Steen","year":"2019","journal-title":"Arthritis Rheumatol"},{"key":"2026100515071248000_kfag125-B40","doi-asserted-by":"publisher","first-page":"1604483","DOI":"10.3389\/fimmu.2025.1604483","article-title":"Treg cell therapy manufacturability: current state of the art, challenges and new opportunities","volume":"16","author":"Stoops","year":"2025","journal-title":"Front Immunol"},{"key":"2026100515071248000_kfag125-B41","doi-asserted-by":"publisher","first-page":"303","DOI":"10.1084\/jem.192.2.303","article-title":"Immunologic self-tolerance maintained by CD25(+)CD4(+) regulatory T cells constitutively expressing cytotoxic T lymphocyte-associated antigen 4","volume":"192","author":"Takahashi","year":"2000","journal-title":"J Exp Med"},{"key":"2026100515071248000_kfag125-B42","doi-asserted-by":"publisher","first-page":"632","DOI":"10.1002\/hep.28459","article-title":"A pilot study of operational tolerance with a regulatory T-cell-based cell therapy in living donor liver transplantation","volume":"64","author":"Todo","year":"2016","journal-title":"Hepatology"},{"key":"2026100515071248000_kfag125-B43","doi-asserted-by":"publisher","first-page":"22","DOI":"10.1016\/j.clim.2009.06.001","article-title":"First-in-man clinical results of the treatment of patients with graft versus host disease with human ex vivo expanded CD4\u2009+\u2009CD25\u2009+\u2009CD127\u2212 T regulatory cells","volume":"133","author":"Trzonkowski","year":"2009","journal-title":"Clin Immunol"}],"container-title":["Toxicological Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/toxsci\/advance-article-pdf\/doi\/10.1093\/toxsci\/kfag125\/71103878\/kfag125.pdf","content-type":"application\/pdf","content-version":"am","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/toxsci\/article-pdf\/209\/10\/kfag125\/71103878\/kfag125.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/toxsci\/article-pdf\/209\/10\/kfag125\/71103878\/kfag125.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,5]],"date-time":"2026-10-05T19:10:22Z","timestamp":1791227422000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/toxsci\/article\/doi\/10.1093\/toxsci\/kfag125\/8799016"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,15]]},"references-count":43,"journal-issue":{"issue":"10","published-print":{"date-parts":[[2026,10,1]]}},"URL":"https:\/\/doi.org\/10.1093\/toxsci\/kfag125","relation":{},"ISSN":["1096-0929"],"issn-type":[{"value":"1096-0929","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,10]]},"published":{"date-parts":[[2026,9,15]]},"article-number":"kfag125"}}