Abstract Details

Read the abstract and find the presentation below

Abstract Text

G2 - Immune Targeting and Approaches with Genetically-Modified Cells and Cell Therapies (Including CAR-T, CAR-NK, TCR editing)

836: THRIVETM Non-Viral Targeted Transgene Knock-In Platform Generates Specific and Potent TCR T Cell Products for the Treatment of Solid Cancers

Type: Poster Session

Poster Board Number: 836
Presentation Details
Session Title: Wednesday Posters: Immune Targeting and Approaches with Genetically-Modified Cells and Cell Therapies

Introduction: Selective and homogenous expression of oncogenic driver mutations such as KRASG12D and p53R175H make them ideal targets for cancer therapies. Adoptive T cell therapies with engineered T cell receptors (TCRs) recognizing mutated driver proteins have led to durable responses in patients with solid tumors. Lentiviral vector (LVV)-based T cell manufacturing suffers from limited cargo size, heterogeneous transgene expression, high manufacturing cost and complexity, and the potential for oncogenesis due to random genomic insertions. To overcome these challenges, we have developed THRIVETM, a non-viral, gene-editing-based T cell manufacturing platform that achieves high rates of targeted transgene insertion and robust cell expansion, and yields potent TCR T cell therapies. Methods and Results: An efficient and specific novel type V CRISPR-Cas system was used for targeted transgene knock-in (KI) at the TRAC locus via homology directed repair (HDR) in primary human CD4+ and CD8+ T cells. The optimized HDR template and engineering process achieved efficient KI and expression of multi-cistronic constructs up to 7 kb in size that included: 1) a TCR specific for an oncogenic driver mutation, 2) a CD8αβ coreceptor allowing for effective CD4+ T cell target recognition and stimulation, and 3) T cell function-enhancing synthetic fusion proteins. Unlike LVV-mediated random insertions, genotypic analysis of THRIVE-produced T cells showed targeted transgene insertion at the TRAC locus that also disrupted the endogenous TCRα chain, resulting in increased surface expression of the transgenic oncogene-specific TCR and enhanced antigen sensitivity. Thus, THRIVE gene-edited T cells demonstrated improved efficacy as compared to LVV-engineered T cells both in vitro during repeat tumor cell challenges and in vivo after single administration in mice harboring tumor xenografts. Gene-editing safety evaluation demonstrated specificity with no off-target activity in high sensitivity (~0.1%) NGS-based analyses or any gene-editing-related chromosomal rearrangements. When evaluated at expected clinical scale, the THRIVE platform yielded up to 50% transgene-positive T cells that showed a favorable T stem cell memory/ T central memory phenotype and >50-fold expansion achieving anticipated dose levels for clinical trials. Conclusion: The non-viral targeted knock-in platform, THRIVE, enables safe and cost-effective T cell engineering with high efficiency. THRIVE-engineered oncogene driver-specific TCR T cells demonstrated superior cytotoxicity against tumor cells relative to LVV-engineered cells both in vitro and in vivo. These data support the clinical readiness and advancement of the THRIVE platform for engineering TCR T cell therapy for the treatment of advanced solid malignancies.

Plain Language Summary
We are developing therapies to treat difficult to cure solid cancers such as pancreatic and colorectal cancer. We utilize body’s own fighter immune cells and program them to identify the cancer cells that bear cancer-causing genes. These programmed fighter cells can find and kill cancer cells in the body. We describe our approach, THRIVETM, to manufacture these programmed fighter cells. Within the THRIVE platform, we insert the therapeutic genes in the fighter cells in an efficient and safe way and grow these cells. In lab setting, we show that our programmed cells kill cancer cells efficiently and spare the normal non-cancer cells. As next steps, we show that we can manufacture these programmed fighter cells in sufficient numbers to potentially allow us to treat patients in clinic. Excited by our results, we plan to test our therapy in patients suffering from devastating solid cancers.

Santosh Narayan1, Nathaniel Swanson1, Allison Drain1, Ken Gareau1, Nicholas Rouillard1, Jinsheng Liang1, Hui-Wen Liu1, Lauren Brown1, Rebecca Lamothe2, Philip D. Greenberg3, Christopher A. Klebanoff4, Ankit Gupta1, Damien Hallet1, Gary Shapiro1, Kim Nguyen1, Loic Vincent1

1Affini-T Therapeutics, Watertown, MA,2Metagenomi Inc., Emeryville, CA,3Program in Immunology and Translational Science and Therapeutics Division, Fred Hutchinson Cancer Research Center, Seattle, WA,4Memorial Sloan Kettering Cancer Center, New York, NY"

Find This Session

This site uses cookies to offer you a better user experience and to analyze site traffic. By continuing to use this website, you accept our use of cookies.