{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,13]],"date-time":"2026-10-13T02:56:37Z","timestamp":1791860197836,"version":"4.3.4"},"reference-count":0,"publisher":"American Society of Hematology","content-domain":{"domain":["ashpublications.org"],"crossmark-restriction":true},"short-container-title":[],"abstract":"<jats:p>This study reports outcomes of PLAT-02, a phase 2 trial of SCRI-CAR19, a second-generation CAR T-cell product with FMC63 scFv and 41BB costimulation, in pediatric and young adult patients with B-cell acute lymphoblastic leukemia; and PLAT-03, a companion study evaluating exogenous CD19 antigen stimulation with serial infusions of T cells expressing truncated CD19, T-cell antigen presenting cells (T-APCs). The efficacy cohort of PLAT-02 (n=72 patients, median age 12.5 years) received fludarabine\/cyclophosphamide lymphodepletion followed by a dose of 1X106 CAR+ T cells\/kg. MRD-negative complete remission rate was 89%. Leukemia free survival (LFS) with 95% CI at 1 and 2 years was 0.71 (0.58, 0.81) and 0.64 (0.51, 0.75). Patients with low disease burden had significantly higher 1-year LFS (0.91 vs. 0.42). Rapid in vivo contraction of CAR T cells after infusion was associated with CAR loss within six months compared to those without rapid contraction (57% vs. 19%, respectively). Most common grade 3\/4 adverse events included cytokine release syndrome in 13% and neurotoxicity in 16%. The companion pilot, PLAT-03, enrolled 26 patients, and 19 received T-APCs. Neither cytokine-release syndrome nor neurotoxicity were observed after T-APC infusion. T-APC infusion in patients improved persistence (P=0.03) with rapid CAR T-cell contraction was associated with decreased early CAR loss (20% with T-APC vs. 57% without). Further exploration of serial artificial CD19 antigen exposure is warranted based on these pilot results. PLAT-02 (NCT02028455) and PLAT-03 (NCT03186118)<\/jats:p>","DOI":"10.1182\/blood.2025028359","type":"journal-article","created":{"date-parts":[[2025,4,15]],"date-time":"2025-04-15T20:13:41Z","timestamp":1744748021000},"update-policy":"https:\/\/doi.org\/10.1182\/blood.2019cm0000","source":"Crossref","is-referenced-by-count":11,"title":["Outcomes of PLAT-02 and PLAT-03: Evaluating CD19 CAR T-Cell Therapy and CD19-expressing T-APC Support in Pediatric B-ALL"],"prefix":"10.1182","author":[{"given":"Colleen","family":"Annesley","sequence":"first","affiliation":[{"name":"Seattle Children's Therapeutics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kristy D.","family":"Seidel","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapuetics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2292-4816","authenticated-orcid":false,"given":"Qian","family":"Wu","sequence":"additional","affiliation":[{"name":"Fred Hutchinson Cancer Center, Seattle, Washington, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1769-7388","authenticated-orcid":false,"given":"Corinne","family":"Summers","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapeutics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alan S.","family":"Wayne","sequence":"additional","affiliation":[{"name":"Children's Hospital Los Angeles, Los Angeles, California, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3030-8420","authenticated-orcid":false,"given":"Michael A.","family":"Pulsipher","sequence":"additional","affiliation":[{"name":"Huntsman Cancer Institute\/Intermountain Primary Chlldren's Hospital, Spencer Fox Eccles School of Medicine, University of Utah., Salt Lake City, Utah, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4898-9615","authenticated-orcid":false,"given":"Anurag K","family":"Agrawal","sequence":"additional","affiliation":[{"name":"UCSF Benioff Children's Hospital Oakland, Oakland, California, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christopher T","family":"Brown","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapeutics, Seattle, Washington, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4652-776X","authenticated-orcid":false,"given":"Stephanie","family":"Mgebroff","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapeutics, United 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Children's Therapeutics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6777-9165","authenticated-orcid":false,"given":"Julie R","family":"Park","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapeutics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1532-3200","authenticated-orcid":false,"given":"Rebecca A","family":"Gardner","sequence":"additional","affiliation":[{"name":"Seattle Children's Therapeutics, United States"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"234","published-online":{"date-parts":[[2025,4,15]]},"container-title":["Blood Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/ashpublications.org\/blood\/article-pdf\/doi\/10.1182\/blood.2025028359\/2369362\/blood.2025028359.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/ashpublications.org\/blood\/article-pdf\/doi\/10.1182\/blood.2025028359\/2369362\/blood.2025028359.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,15]],"date-time":"2025-04-15T20:13:41Z","timestamp":1744748021000},"score":1,"resource":{"primary":{"URL":"https:\/\/ashpublications.org\/blood\/article\/doi\/10.1182\/blood.2025028359\/536722\/Outcomes-of-PLAT-02-and-PLAT-03-Evaluating-CD19"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,15]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1182\/blood.2025028359","relation":{},"ISSN":["0006-4971","1528-0020"],"issn-type":[{"value":"0006-4971","type":"print"},{"value":"1528-0020","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,4,15]]},"article-number":"blood.2025028359"}}