Abstract CT269: Point-of-care manufacturing and early clinical evaluation of a tri-specific (CD19/20/22) CAR T-cell therapy for relapsed or refractory (R/R) B-cell malignancies

Abstract Introduction: Despite the clinical success of CD19-directed CAR T-cell therapy, antigen downregulation or loss leading to relapse remains a major limitation in R/R B-cell malignancies. Post-relapse biopsies frequently retain alternative B-cell antigens, including CD20 and CD22, supporting multi-antigen targeting strategies. Here, we report an ongoing Phase 1 first-in-human trial evaluating the safety, feasibility, and preliminary efficacy of DuoCAR20. 19. 22-D95, a tri-specific CAR T-cell therapy, in adults with R/R B-cell malignancies. Methods: This open-label early phase investigator-initiated study enrolls adults (≥18 years) with R/R B-cell acute lymphoblastic leukemia (B-ALL) or B-cell non-Hodgkin lymphoma (B-NHL), including follicular lymphoma, marginal zone lymphoma, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). Autologous peripheral blood mononuclear cells are collected by leukapheresis, and CAR T cells were manufactured in-house using the Miltenyi CliniMACS Prodigy® closed system for T-cell enrichment, activation, lentiviral transduction, and expansion. The bicistronic lentiviral construct encoding CARs targeting CD19, CD20, and CD22 with OX40 and ICOS co-stimulatory domains was provided by Lentigen. Patients receive lymphodepleting chemotherapy with fludarabine and cyclophosphamide followed by a single intravenous infusion of DuoCAR20. 19. 22-D95. Phase 1 employs a standard 3+3 dose-escalation design (planned doses: 1-3 × 10⁶ CAR T cells/kg) to determine the maximum tolerated dose and recommended Phase 2 dose. Primary endpoints include safety, dose-limiting toxicities, and manufacturing feasibility; secondary endpoints assess efficacy, CAR T-cell expansion, and persistence. Results: Enrollment is ongoing. As of the data cutoff, six patients underwent leukapheresis, with successful CAR T-cell manufacturing in five patients (83%), all were infused at dose level 1 (1 × 10⁶ CAR T cells/kg). The median age was 46 years, with both sexes represented. Diagnoses included B-ALL (n=1) and R/R B-NHL (n=5), predominantly DLBCL. Patients were heavily pretreated with all but one had received prior commercial CD19 CAR T-cell therapy, with two post-autologous and one post-allogeneic transplant. No dose-limiting toxicities were observed. CRS was limited to grade 1 in two patients, and no ICANS. CAR T-cell expansion was detected in peripheral blood by flow cytometry and/or qPCR. Among evaluable patients at day +30, responses included CR (n=1), PR (n=2), SD (n=1), and PD (n=1). One patient with B-ALL had an isolated CNS relapse and achieved CR following CNS-directed therapy. All patients remain alive, and day +90 assessments are ongoing. Conclusions: These early data demonstrate the feasibility of point-of-care manufacturing, a favorable safety profile, and preliminary antitumor activity of a first-in-human, investigator-initiated tri-specific CD19/20/22 CAR T-cell therapy, supporting further dose escalation and expansion. Citation Format: Joseph P. McGuirk, Rupal Soder, Ramesh Balusu, Nathaniel Dudley, Louisa Wirthlin, Tyce Bruns, David Akhavan, Scott J. Weir, Sunil Abhyankar. Point-of-care manufacturing and early clinical evaluation of a tri-specific (CD19/20/22) CAR T-cell therapy for relapsed or refractory (R/R) B-cell malignancies abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts) ; 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86 (8Suppl): Abstract nr CT269.