Abstract 3245: FT819 path to IND: First-of-kind off-the-shelf CAR19 T-cell for B cell malignancies
Authors: Mandal Mili , Clarke Raedun , van der Stegen Sjoukje , Chang Chia-Wei , Lai Yi-Shin , Witty Alec , Husain Mushtaq , Wu Cheng-Jang , Yang Bi-Huei , Dufaud Chad , Hsia Gloria , Shaked Helena , Stokely Laurel , Chu Helen , Pribadi Mochtar , Hernandez Gilberto , ORourke Jason , Gutierrez Alma , Abujarour Ramzey , Lee Tom , Stefanski Jolanta , Zhen Juan , Wu Meilan , Riviere Isabelle , Sadelain Michel , Valamehr Bahram 
Published: September 2020

Abstract
Genetic engineering of T cells using a chimeric antigen receptor targeting CD19 antigen (CAR19) is now a well-established treatment of B cell malignancies. While cellular immunotherapies are entering front line treatment, substantial limitations currently hamper the broad application of adoptive T cell therapies in diverse patient population including dysfunctional starting material, lack of product consistency and purity post genetic engineering and inefficient quantity produced for true on-demand availability. FT819 is a first-of-kind off-the-shelf CAR19-T cell product generated from a renewable pluripotent stem cells for large-scale clinical manufacturing. We previously reported the engineering and characterization of the FT819 clonal master cell bank (MCB) derived from a single cell comprising targeted integration of a novel CD19 1XX CAR into the T-cell receptor (TCR) α constant locus to provide optimally regulated CAR expression and elimination of graft versus host (GvH) response. Here we preview the nonclinical study for the original investigational new drug application of FT819. Derived in a manufacturing process analogous to pharmaceutical drug product development, pilot runs from the MCB demonstrated FT819 can be consistently and uniformly manufactured in cGMP compliance, cryopreserved at clinical scale to support off-the-shelf clinical application with greater than 1e5 fold increase in cellular yield from the starting MCB and can be thawed and directly used for facilitated treatment. Repeatedly, FT819 displayed a uniform product profile of ≥95% CAR+, TCR-, CD45+, CD7+ and CD3+ [intracellular] with majority of CD8 T cells expressing CD8β. FT819 global gene expression profile displayed high similarity to primary CAR19-T cells confirming its identity as a T lymphocyte. Functional assessment demonstrated that FT819 possesses potent antigen specific cytolytic activity against leukemia and lymphoma cell lines (p=0.0004). Additional specificity studies demonstrated on-target, off-tumor cytolysis of CD19+ B cells in mixed lymphocyte reaction assay (85% lysis of CD19+ B cells versus &lt; 2% lysis of T cells). Inability of FT819 to produce a GvH response was confirmed in a co-culture assay with anti-TCR crosslinking antibodies. Disseminated leukemia xenograft mouse studies demonstrated the ability of directly thawed and infused FT819 to control tumor growth (p=0.0003 at day 21). In a systemic administered leukemia model FT819 also showed sustained localization in the bone marrow up to 45 days post injection. Ongoing in vivo studies will assess long-term survival and avoidance of GvH disease. Collectively, these studies demonstrate that FT819 is a potent, consistent and uniform CAR19 T cell product and can be effectively and safely used off-the-shelf in the treatment of B cell malignancies with an original Phase 1 clinical trial planned in 2020.
Citation Format: Mili Mandal, Raedun Clarke, Sjoukje van der Stegen, Chia-Wei Chang, Yi-Shin Lai, Alec Witty, Mushtaq Husain, Cheng-Jang Wu, Bi-Huei Yang, Chad Dufaud, Gloria Hsia, Helena Shaked, Laurel Stokely, Helen Chu, Mochtar Pribadi, Gilberto Hernandez, Jason ORourke, Alma Gutierrez, Ramzey Abujarour, Tom Lee, Jolanta Stefanski, Juan Zhen, Meilan Wu, Isabelle Riviere, Michel Sadelain, Bahram Valamehr. FT819 path to IND: First-of-kind off-the-shelf CAR19 T-cell for B cell malignancies [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3245.