Abstract A54: Epi-RTM (epigenetic reprogramming) technology improves stemness, preserves polyclonality and enhances antitumor functionality of tumor infiltrating lymphocytes in nonclinical studies
Authors: Patel Yogin , Ha Ngoc-Han , Bedard Melissa , Kritikou Joanna , Kishton Rigel , Vodnala Suman Kumar 
Published: December 2022

Abstract
Background: Adoptive cell therapy (ACT) is an evolving area for drug development in advanced solid tumors. Tumor infiltrating lymphocyte (TIL) therapy as an autologous ACT has shown promising efficacy in select solid tumor types, eliciting clinical responses through tumor specific antigen recognition and maintaining T-cell receptor (TCR) diversity. Growing evidence indicates that TIL products with increased T-cell stemness, tumor antigen recognition, and clonal diversity may result in improved clinical outcomes. Epi-R reprogramming technology is designed to improve T-cell stemness, polyclonality, and antitumor functionality in ACT products, including TIL. Method: The Epi-R protocol is composed of an extensively formulated proprietary cell culture media and well-defined cytokines with specific cell activation and expansion manufacturing parameters and methods. In nonclinical experiments, research-scale TIL products were produced from 3 different tumor types (melanoma, lung, and colorectal cancer) using either the Epi-R technology or a standard protocol (control TIL). Characteristics of the resulting products were compared using flow cytometry to assess stemness markers. An autologous cell line was generated from a melanoma patient tumor, and antitumor function and cytokine production were measured upon co-culture with the TIL products. Clonal diversity was assessed using TCR Vbeta sequencing. Results: Nonclinical evaluations of Epi-R TIL demonstrated increased stemness, functional cytokine production and antitumor activity compared to control TIL. Epi-R TIL products were enriched for CD8+ T cells, co-receptor (CD27 and CD28) positive CD8+ T cells, and stem-like CD8+ T cells, as demonstrated by enrichment for CD39-CD69- T cells compared to control TIL. Epi-R TIL demonstrated superior functionality by IFNg response upon co-culture with an autologous melanoma tumor cell line. Polyclonality was preserved in Epi-R TIL as measured by Simpson clonality index using bulk TCR Vbeta sequencing data. Conclusion: Results from research-scale TIL productions demonstrated that Epi-R reprogramming technology enables successful TIL expansion while maintaining a greater proportion of stem-like and co-stimulatory positive CD8+ TIL with preserved polyclonality compared to control TIL. Moreover, Epi-R TIL show improved antitumor activity compared to control TIL product in a melanoma tumor cell line. Further studies of Epi-R TIL using RNA sequencing will allow further characterization of this product and determine whether key product attributes are maintained at large-scale TIL manufacturing. An Investigational New Drug (IND) submission for LYL845, our autologous TIL product manufactured with Epi-R reprogramming technology, for melanoma and other advanced solid tumors is anticipated to occur in the second half of 2022.
Citation Format: Yogin Patel, Ngoc-Han Ha, Melissa Bedard, Joanna Kritikou, Rigel Kishton, Suman Kumar Vodnala. Epi-RTM (epigenetic reprogramming) technology improves stemness, preserves polyclonality and enhances antitumor functionality of tumor infiltrating lymphocytes in nonclinical studies [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr A54.